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Mark Bayley

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Blog Entries posted by Mark Bayley

  1. Mark Bayley
    I am enrolled at UNIS,Svalbard, studying Arctic glaciers till September. I am hoping to keep this blog updated with details of what I am up to and pictures. So far I am limited to Longyearbyen, having not received gun training, but next week will start with fieldwork. The weather has so far been sunny, and rather warm, reaching a high of 15c yesterday. The constant light is taking some getting use too! I'll be visiting a local glacier on Thursday, where I hope to update!
  2. Mark Bayley
    So I have finally been able to go out in the field. My first trip was to Tempelfjorden tidewater glacier. This glacier has the highest surge rate in the Svalbard region. Sadly we could not get close, for obvious reasons; calving. When arriving I was lucky enough to witness a carving event, although not of great magnitude. I have attached a few images of the calving front, which was several hundred meters. Not the englacial feature in the zoomed picture.
    [attachment=257846:P8070012.JPG][attachment=257847:P8070013.JPG][attachment=257848:P8070014.JPG][attachment=257850:P8070019.JPG]
    We later docked on the adjacent beach. The aim was to reach a local mountain glacier. This involved crossing very rough pro-glacial deposits (and moraines). One particular feature stood out (2nd picture). Uncertainties exist as to the cause of such feature, although note the roughness of the surrounding terrain in comparison to the rounded rock. It is thought this is a feature of moulon and subglaical channel. Although of course the glacier must have been in position for considerable time to cause such rounding. I also attach a picture of ground water. Was amazing how clear the spring water was.
    [attachment=257843:Glacial sediments.jpg][attachment=257849:P8070016.JPG][attachment=257845:Groundwater.jpg]

    Sadly when reaching the glacier terminus we where halted by a powerful pro-glacial river. Ice melt has been high in recent weeks, making a crossing dangerous.
    [attachment=257852:Pro-glacial river.jpg]
    Although disappointing, see a calving glacier more than made up for it. I shall be on the ice Monday. I hope to update then!

    Oh, and here is a mini iceberg
    [attachment=257853:Iceberg.jpg]

    As a side note, I have some video of the calving front, maybe i could try an upload?
  3. Mark Bayley
    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]2014/15 Winter Forecast [/b][/center][/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center]My attempt at a winter forecast. Some of the theory is taken from a previous project i undertook at University. I have attached references that i have used/think may be of interest. Apologies if it does not flow well. Apparently i am dyslexic although i've read over it a few times and i think its devoid of mistakes![/center][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    [b]Factors considered[/b][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [font=symbol]· [/font]QBO[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [font=symbol]· [/font]October snow cover[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [font=symbol]· [/font]Autumn sea ice extent[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [font=symbol]· [/font]ENSO[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [font=symbol]· [/font]Solar output[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [font=symbol]· [/font]Long range models[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [font=symbol]· [/font]OPI (briefly)[/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]QBO[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    The quasi-biennial oscillation (QBO) is a quasiperiodic fluctuation of the equatorial zonal wind in the tropical stratosphere between the westerlies and easterlies. In westerly phase stratospheric warming events during winter occur less frequently. Last winter theQBO was in westerly phase, contrasting to this winter, where it is in easterly phase. Stratospheric warming events are more common in this phase. I’ll not bog down with the physics and processes, so will leave it at this. The current phase of the QBOfavours a colder than average winter. See further information if you wish to read more on the QBO. [/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/qbo/"]Current/past phases of the QBO (note shaded area equates to westerly winds)[/url][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [img]http://www.geo.fu-berlin.de/met/ag/strat/produkte/qbo/qbo_wind.jpg[/img][/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]October Snow cover[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    October Eurasian snow cover anomalies have been correlated with the wintertime AO (see Cohen et.al., 2011 at the end). Cold and dense air associated with snow cover promotes high-pressure formation, whereas warmer buoyant air over ice-free landmass promotes lower pressure formation. More expansive and stronger Siberian high-pressure systems are therefore favoured during years of greater autumn snow cover. Cohen and Entekhabi, (1999) first proposed a strengthened Siberian high leads to increased atmospheric wave breaking into the stratosphere. Such events can in turn lead to a phenomenon known as sudden stratospheric warming. Preceding sudden stratospheric warming events atmospheric waves propagating into the stratosphere decelerate upper westerly zonal winds (e.g. Martius et al., 2009). During strong atmospheric wave breaking events, found to be associated with a stronger and more expansive Siberian high, mean zonal winds may reverse (become easterly) and thereafter sudden stratospheric warming occur (Martius et al., 2009). This prevents further atmospheric wave breaking penetrating into the stratosphere, causing downward propagation of stratospheric easterly winds and warming into the underlying troposphere. Zonal wind reversal in the troposphere leads to disruption of the polar vortex and formation of positive height anomalies (-AO). Colder air is thereafter displaced into the mid-latitudes by -AO[/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    The recent Eurasian October snow cover extent was amongst the highest on record. I reconstructed 1000mb Geopotential heights for the lowest/highest October snow cover years. For the highest snow cover years I narrowed down to those months that occur within the easterly phase of the QBO (n at end of section). [size=4]A strong signal for positive height anomalies across Greenland is present during high snow cover years that occur in the easterly phase for the QBO (+SC/easterly QBO). In contrast a strong signal for lower than normal heights is present for years that occur during low snow cover years and the westerly phase of the QBO (-SC/westerly QBO). A greater southerly track of the jet stream is also found.[/size][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [size=4]Left: [/size]-SC/easterly QBO Right : [size=3]+SC/westerlyQBO[/size][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-92671400-1416177202.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-92671400-1416177202_thumb.png[/img][/url] [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-45118800-1416177203.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-45118800-1416177203_thumb.png[/img][/url][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [size=4]Left: [/size]-SC/[size=3]easterly[/size] QBO Right : [size=3]+SC/westerlyQBO[/size][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-90194500-1416177205.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-90194500-1416177205_thumb.png[/img][/url] [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-42269200-1416177206.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-42269200-1416177206_thumb.png[/img][/url][/size][/font][/color]
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    An stronger signal for positive height anomalies occurs in January during +SC/easterly QBO years. In contrast, lower than normal heights (i.e. +AO) occurs during -SC/westerly QBO. The mean jet stream position during +SC/eastly QBO years is south of the UK, which contrasts to -SC/westerly QBO years, where it is across the UK (i.e. a wet and often mild winter results!)[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [size=4]Left: [/size]-SC/[size=3]easterly[/size] QBO Right : [size=3]+SC/westerlyQBO[/size][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-89726700-1416177204.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-89726700-1416177204_thumb.png[/img][/url] [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-41892000-1416177205.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-41892000-1416177205_thumb.png[/img][/url][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [size=4]Left: [/size]-SC/[size=3]easterly[/size] QBO Right : [size=3]+SC/westerlyQBO[/size][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-90012200-1416177206.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-90012200-1416177206_thumb.png[/img][/url] [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-40162000-1416177207.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-40162000-1416177207_thumb.png[/img][/url][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    Similarly a strong signal for positive height anomalies during +SC/easterly QBO years is found in February. In contrast, lower than normal heights (i.e. +AO) occurs during low snow cover/westerly QBO years. I forgot to reconstruct mean jet stream position, however it is clear that during +SC/easterly QBO years that the jet stream is to the south of the UK based upon the 1000mb geopotential height anomalies.[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [size=4]Left: [/size]-SC/[size=3]easterly[/size] QBO Right : [size=3]+SC/westerlyQBO[/size][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-91645300-1416177203.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-91645300-1416177203_thumb.png[/img][/url] [url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-40788300-1416177204.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-40788300-1416177204_thumb.png[/img][/url][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    The mean index value for the AO during +SC/eastly QBO years is; -1.01 December (n12); -0.97 January (n12); -1.44 February (n10). No strong signal for the NAO exists (albeit a weak negative signal for December and February); -0.31 December; 0 January; -0.33 February.[/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    In summary a clear signal for -AO during winters that occur in +SC/easterly QBO years is present. However, there is no strong temperature signal for the UK (also note a weaker forcing on the NAO). Despite that, -AO will support greater periods of prolonged cold across the UK, should the segments of the PV fall into the right position (which is most important, and crucial to recognise despite great AO forcing, stratospheric warming evetns DO NOT automatically result in UK cold). To conclude; this year’s snow cover, accompanied by the phase of the QBO, is supportive of atmospheric conditions (i.e. -AO) conducive to a colder than average winter.[/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]Autumn sea ice conditions[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    During low sea ice years higher geopotential heights over the Arctic occurs (see Jaisor et.al., 2012). This is attributed to an increase in the temperature of the lower troposphere (via an increased transfer of heat from the open ocean). Warmer air is less dense and therefore forms an area of increased geopotential thickness. Greater geopotential heights oppose the normal polar vortex Arctic westerlies, and instead favour meridional flow, supporting -AO (note other feedbacks exist; see attached literature). Others (e.g. Liu et al., 2012) have noted that a decrease in Arctic sea ice is associated with an increased occurrence of winter high-pressure blocking systems in the high latitudes, most particular in Eastern Europe, Siberia, Alaska and the North West United states. Recent studies have noted that sea ice anomalies around the Kara and Laptev sea have a strong forcing on the AO (e.g. [size=3]Baek-Min et.al., 2014[/size][size=4]). This year sea ice extent was negative, however not as low as years previous. Sea ice extent was also higher in the aforementioned regions, thus it may be expected that this year’s sea ice anomalies potential to force -AO may be less strong than previous winters. Despite this sea ice extent is still at record lows, and based on other climatic feedbacks, I’d suggest is still supportive of a colder than average winter.[/size][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="http://nsidc.org/arcticseaicenews/"]October sea ice extent[/url][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [img]http://nsidc.org/arcticseaicenews/files/2014/11/Figure1-350x417.png[/img][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    [size=4]Seasonal anomalies in 1000-500 hPa thicknesses (m) north of 40 N for 2000–2010 (years of low sea ice) relative to 1970–1999 (years of high sea ice): a) autumn; b) winter. White crosses indicate statistical significance. Reproduced from Franics and Varvus, (2012). Lower sea ice correlates strongly with increased [/size]occurrence[size=4] of winter [/size]blocking[size=4] systems[/size][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [size=4][url="https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-33543400-1416179707.png"][img]https://f1.nwstatic.co.uk/forum/uploads/monthly_11_2014/post-6181-0-33543400-1416179707_thumb.png[/img][/url][/size][/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]ENSO[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    Recent work has shown that ENSO, when close to neutral, has a minimal impact on the northern hemisphere mid-latitude weather patterns. Some such as Cohen suggest that ENSO, unless strong, is relatively useless in winter forecasting. Weak to moderate El Ninos have however been correlated with colder than average winters across NW Europe (although not strongly). At present El Nino is weak, and is not predicted to gain significant strength during winter . The current ENSO pattern therefore favours a colder than average winter. Unfortunately I am unable to cover ENSO in the depth [size=3]of [/size][size=3]snow [/size][size=3]cover [/size][size=4]and [/size][size=3]sea ice[/size][size=4], mainly as the charts posted are being used as part of my research project.[/size][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing/sstaa.gif"]E[/url]NSO long range prediction[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [img]http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing/sstaa.gif[/img][/size][/font][/color]


    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]Solar output[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    Increased solar output favours milder than average winters. Currently solar activity has picked up, although is not notably strong. No strong winter signal is favoured from current solar activity.[/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="http://www.climate4you.com/Sun.htm"]Current sun spot activity[/url]. Note the increase since 2010[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [img]http://www.climate4you.com/images/SIDC%20DailySunspotNumberSince1977.gif[/img][/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]Long-range climate models[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    A number of long range forecast models are/where predicting a milder than average winter (e.g. CFS). Long range forecast models may not take into account snow and sea ice feedbacks. Often, long-range forecast models turn out to be wrong (e.g. CFS). Although not discounted, little emphasis is placed on these models. To summarise, the output from long range climate models favours a milder than average winter.[/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]OPI[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    Not really got time to cover this so I refer everyone to OPI thread where there has been some excellent analysis by the likes of Steve Murr and others. A relationship between the OPI and AO has been noted, with correlations as strong as 0.9. Further to this a good relationship between the OPI and CET is noted (-OPI correlates with below uk temps). The final OPI figure was amongst the most negative of those recorded. This would add further support to atmospheric conditions (i.e. -AO) conducive to UK cold winter! [/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    [url="http://app.til.it/opi/"]http://app.til.it/opi/[/url][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]Summary[/b][/center][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    I favour colder than average winter with at least one month to return a notable -AO figure. At present I favour January with a significant stratospheric warming event to occur during late December/early January based on the strats present situation and a gut feeling, but also Cohens work on when warmings are most likely to occur (see strat thread). February may produce the greatest -AO return based on snow cover analysis. December may prove to be mildest month, although with a disrupted PV, colder spells would seem likely, as shown by the reanalysis. Thank-you for reading [font=wingdings]J[/font][/size][/font][/color]

    [color=rgb(40,40,40)][font='Open Sans'][size=3][center][b]Further information[/b][/center][/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    Some useful papers for further reading. Or try googling, tons will come up![/size][/font][/color]
    [color=rgb(40,40,40)][font='Open Sans'][size=3]
    An overview of the QBO at Richter et.al., (2011) 'Influence of the quasi-biennial oscillation and ENSO on the frequency of sudden stratospheric warmings' Or see this [url="http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/qbo/"]link[/url][/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    A good paper where the snow cover/AO linkages are first noted. 'Eurasian snow variability and northern hemisphere climate variability' by Judah Cohen and Dan Entekhabi (1999) [/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    The snow cover theory has been developed by Judah Cohen. See - 'Eurasian Snow Cover Variability and Links with Stratosphere-Troposphere Coupling and Their Potential Use in Seasonal to Decadal Climate Predictions' for more information'[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    See Martius et al., (2009) 'blocking precursors to sudden stratospheric warming events' for an good overview on the strat and conditions that can cause warming events [/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    See Jaiser et al. (2011) for sea ice feedbacks with the stratosphere. ‘Stratospheric response to Arctic sea ice retreat and associated planetary wave propagation changes’ [/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    See Liu et.al., 2012 for a good overview of arctic sea ice and the influence on blocking patterns/winter snow fall. 'Impact of declining Arctic Sea ice on winter snowfall'[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    See Francis and Varvus (2012) for an overview of sea ice and its influence on seasonal atmosphere circulation. 'Evidence linking Arctic Amplification to extreme weather in the mid-latitudes'[/size][/font][/color][color=rgb(40,40,40)][font='Open Sans'][size=3]
    See Baek-Min et.al., (2014) for a recent study on regional ice loss and the impact on the AO 'weakening of the stratospheric polar vortex by Arctic sea-ice loss'[/size][/font][/color]
  4. Mark Bayley
    [b]January forecast[/b]

    [b]Previous update[/b]
    [color=#282828][font=helvetica, arial, sans-serif]I expect the continuation of unsettled conditions, with on average temperatures remaining close to the norm. Given the expected continuation of a –NAO, and –AO I would not bet against colder interludes, in the form of brief northerlys, as we progress through the xmas period (something which has shown around xmas day on the latest model runs). I do not see great support for something prolonged this side of New Year. Given developments in the stratosphere I think the first half January, probably past week one, is when it could potentially come very interesting..![/font][/color]

    [b]Review[/b]
    [color=#282828][font=helvetica, arial, sans-serif]It remained unsettled and mostly average, although cooler at times further north. Although the NAO and AO remained negative, they have now trended towards positive, and likely to be so as we start January. Something hinted by the ensemble forecasts in my last update. Those 'interesting developments in stratosphere' seem likely to develop, although as highlighted in the last update, no impact on us is expected by week one. The initial forecast went bust, however the update has got relatively better, although perhaps milder than i expected.[/font][/color]

    [b]Stratospheric outlook[/b]
    [color=#282828][font=helvetica, arial, sans-serif]After a period of temperatures at just below average at 10hpa, and recently just above at 30hpa, a large spike at all levels is expected as we progress into January.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150342"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-07620200-1356787986_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150343"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-59528500-1356787987_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150353"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-89853500-1356788018_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150352"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-52127700-1356788017_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]Stratospheric temperatures at the 10hpa and 30hpa level are to increase significantly during the New Year period. The strength of the warming should lead to significant disruption of the polar vortex, and thus high latitude blocking.[/font][/color]

    [color=#282828][font=helvetica, arial, sans-serif]Mean zonal winds are expected to decrease, reversing at 30hpa, and then most probably at 10hpa. Although not a sudden stratospheric warming (yet), I would expect this to be shown soon (zonal wind reversal at the 10hpa). Again, this should lead to significant disruption of the polar vortex.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150345"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-42468800-1356787990_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150346"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-67200500-1356787991_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]

    [color=#282828][font=helvetica, arial, sans-serif]Split or displacement? I would probably suggest a displacement followed by a possible split. Wave one breaking is expected to increase significantly, before decreasing at the end of the forecast period. Wave one breaking is characterised with vortex displacement.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150344"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-18309800-1356787989_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150339"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-37589200-1356787979_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]Interestingly, wave two breaking is forecast to increase, which favours vortex split.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150365"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-70651100-1356788061_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]It is difficult to predict the area where the displaced vortex is likely to locate. At the moment I would suggest our side of the Atlantic (west Greenland area), which is not favourable for us. However, there are hints from the longer range GFS that subsequent warming nearer midmonth (Greenland area) may change this situation![/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150348"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-59555900-1356788005_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150368"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-93610100-1356788246_thumb.png[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]

    [b]MJO[/b]
    [color=#282828][font=helvetica, arial, sans-serif]A mixed output from the global models, although all indicate an increasing amplitude. The UKMO is by far the most interesting, and has for some time indicated a possible phase 7/8 by midmonth. The ECM is similar to the UKMO, although slower with its evolution. The GFS seems to be on its own, although the bias corrected ensembles seem to follow the euros, albeit slower.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150364"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-51889800-1356788042_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150347"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-93694800-1356788003_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150363"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-16826000-1356788042_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]Some not so good phases to get through beforehand, which in general indicate lower heights to our north, with higher pressure progressively shifting north, so becoming settled.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150357"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-74529300-1356788037_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150358"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-76363400-1356788038_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150359"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-81589200-1356788039_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]Phase 7/8 would support height rises towards Greenland, around or just past midmonth (based on the UKMO/ECM).[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150360"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-41577800-1356788040_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150361"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-99721700-1356788040_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]The GWO has progressed towards phase 4, with a corresponding increase in angular momentum. From reading a few papers I noted how this is associated with a higher amplitude and progression of the MJO, which is ideal for a progression towards phase 7/8. Although given my relatively basic understanding of atmospheric angular momentum (first year uni) I shall not delve on this topic.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150355"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-00013000-1356788021_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150337"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-87940800-1356787975_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]Interestingly the following composites show a GWO phase 5/6/7/8 is associated with below average UK temperatures.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150356"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-62348500-1356788036_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]

    [b]CFS charts[/b]
    [color=#282828][font=helvetica, arial, sans-serif]Although not the most reliable charts, the general trend for weeks one-two is for lower heights to our north, with higher heights to our south (+NAO). With a trend for these higher heights to push further north (i.e. the UK becoming settled at last).[/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]Past midmonth there is a signal for height rises over Greenland, with uncertainties in the placement of the trough.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150366"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-99912600-1356788062_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150367"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-36115900-1356788064_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]

    [b]AO and NAO Ensembles[/b]
    [color=#282828][font=helvetica, arial, sans-serif]The ensembles continue to show +NAO and +AO as we beguine the new year. However, there are some indications from the GFS that the AO shall return negative towards mid-month, which is expected.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150350"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-25846400-1356788012_thumb.png[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]The NAO forecasts are rather disappointing, and show a +NAO towards mid-month[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150351"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-65644400-1356788016_thumb.png[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color][url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150341"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-00728600-1356787984_thumb.png[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]

    [b]Mean height ensembles [/b][color=#282828][font=helvetica, arial, sans-serif](some charts missing due to update issues)[/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]The ECM maintains lower heights to our north, with higher pressure encroaching from the south. So becoming more settled as we progress through the next 5-10 days.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150338"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-42567800-1356787977_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]The GFS is similar, with lower heights to our north west, with high pressure encroaching from the north, attempting to progress north eastwards.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150349"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-64132200-1356788007_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]Which is supported by the stratospheric geopotential height charts[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150340"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-07737500-1356787981_thumb.gif[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    [color=#282828][font=helvetica, arial, sans-serif]The NAEFS shows this high sinking towards midmonth, but with fait signs if height rises towards Greenland.[/font][/color]
    [url="http://forum.netweather.tv/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=150362"][img]http://forum.nwstatic.co.uk/uploads/monthly_12_2012/post-6181-0-69376800-1356788041_thumb.png[/img][/url][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]

    [b]Overall[/b]
    [color=#282828][font=helvetica, arial, sans-serif]An unsettled start to the month, but becoming progressively drier as higher pressure attempts to progress north east. Thereafter potentially becoming unsettled again. Midmonth I expect a change towards much colder conditions, with height rises in the Greenland region (around day 15 ish). I expect colder conditions, if they materialise, to be relatively sustained. In summary, a mild start (cooler when settled), and a cold end.[/font][/color]
  5. Mark Bayley
    [b]Initial forecast[/b]

    Overall im finding it rather difficult to produce a forecast, but then isn’t it always! What’s apparent is the PV shall remain disrupted and disorganised as we progress through December. I am generally supportive of height rises to the NE given the latest runs, although feel that these will transfer nearer Greenland as we progress through the month when we see further wave breaking disrupting the vortex and leading to more movement of the PV segments. This would also be supported by the GFS MJO outlook, and ensemble forecasts for the NAO from both the ECM and GFS. The CFS could also be included. Weatherwise a cold and unsettled start, with the potential for height rises to out NE, and some sort of easterly flow during the first third. As we progress into midmonth and beyond I feel higher pressure would transfer closer to Greenland, bringing a more N/NE’rly flow.

    [b]Review so far[/b]

    The month started on a cold and unsettled note, while expected height rises to the north east materialised. Unfortunately we did not see the easterly flow that i expected, with low pressure from the west taking control, introducing unsettled weather with temperatures close to the average. Despite this the PV has remained disrupted, with a -AO and -NAO which has prevented us from experiencing something from winters past (i.e. Bartlett type weather). It’s apparent that my forecast of midmonth height rises over Greenland via retrogression from scandi will not materialise, and thus a north/north east flow.

    [b]Update and initial January thoughts[/b]

    The following update and forecast is based on the latest stratospheric output, MJO, CFS, AO and NAO ensemble means, as well as 500hpa and 850hpa means.

    [b]Stratospheric outlook[/b]

    [font="helvetica, arial, sans-serif"][color="#282828"]Stratospheric temperatures at the 10hpa and 30hpa level are running just below the average, and have done since a small warming event at the beginning of the month. They are forecast to remain just below average for the next 10 days, with temperatures rising at 30hpa by day 10 (as shown on the ECM temperature charts). Note i have used the graphs for simplicity.[/color][/font]
    [attachment=149126:temp graphs.gif]
    [color=#282828][font=helvetica, arial, sans-serif]Although not as apparent on the temperature graph, a major warming at the 10hpa level is forecast from day ten onwards (Siberian sector), this is shown the ECM 10hpa geopotential height charts at day and ten, and the GFS strat charts.[/font][/color]
    [attachment=149116:ECM t240 10hpa.gif][attachment=149130:gfs_t10_nh_f240.gif]
    [color=#282828][font=helvetica, arial, sans-serif]The most significant warming is still out of range for above charts, however the GFS 12z strat charts show this nicely, and have done for some time (and are not pushing back)[/font][/color]
    [attachment=149123:gfsnh-10-348.png]
    I suspect this will lead to major disruption of the PV, or the killer blow seen as its not exactly rampant at present. This would be expected as we progress into January. For the rest of December, I expect the continuation of the relatively weak PV, centred towards the Siberia, which opens up potential for height rises over Greenland.
    [attachment=149113:ECM geo t240.gif]
    Zonal winds have risen slightly since a drop at the beginning of December, and are forecast to decrease again. Given their current and predicated strength I would expect the continuation of a weak(ish) PV.
    [attachment=149124:graphs zonal.gif]
    Further wave breaking is forecast by day ten, most notable wave one. This should displace the PV, and further stress it. It is also noted that wave two activity shows signs of increasing, which would place even greater stress on already strained PV.
    [attachment=149128:wave one.gif][attachment=149129:wave two.gif]

    [b]MJO outlook[/b]

    There seems consensus to progress the MJO into phase two, although not of high amplitude.
    [attachment=149119:GFS mjo.gif][attachment=149114:ECM mjo.gif][attachment=149127:UKMO mjo.gif]
    The UKMO is interesting in that wants to progress the MJO through higher amplitude phase one beforehand, which would give the following composite which has height rises over Greenland and a trough over the UK (although bear in mind these are to be used as guides).
    [attachment=149111:DecemberPhase1500mb.gif]
    The composite for phase two MJO is the following
    A trough with the core of lower heights situated over the UK (i.e. unsettled)
    [attachment=149112:DecemberPhase2500mb.gif]

    [b]CFS charts[/b]
    [color=#282828][font=helvetica, arial, sans-serif]Weeks one and two show a trough situated in the Atlantic, unfavourably for us, leading to unsettled and probably mild (at times), weather. Looking at all forecasts from Sunday 9[/font][/color][sup]th[/sup][color=#282828][font=helvetica, arial, sans-serif] there seems a trend for height anomalies to continue above the norm around Greenland as progress past xmas day and into new year, with the core of lower heights transferring from the Atlantic into Europe. This would open the door to something a little more seasonal (e.g. northerly airstream).[/font][/color]
    [attachment=149110:CFS week one-two.gif][attachment=149131:weeks three-four.gif]

    [b]AO and NAO Ensembles[/b]

    The ensembles support the continuation of a –AO, although trending towards positive as we move towards months end and then negative again.
    [attachment=149118:GFS AO.png]
    Further to this there is support for the continuation of a mostly –NAO, although trending towards positive for months end.
    [attachment=149120:GFS NAO.png][attachment=149115:ECM NAO.png]

    [b]Mean height ensembles[/b]

    The ECM ensemble mean supports the continuation of higher pressure to the north (Greenland area) and the core of lower heights in the Atlantic, with the continuation of unsettled weather.
    [attachment=149117:ECMWFENS6-10day500mbHeightAnomalyNH.gif]
    Analysis of the 850hpa anomalies would indicate that temperatures should remain close to average, despite being unsettled.
    [attachment=149108:00zecmwfenshourly850mbTempAnomalyNH216.gif][attachment=149109:00zecmwfenshourly850mbTempAnomalyNH240.gif]
    The GFS is similar, although perhaps more interesting by day ten to fifteen, with the core of lower heights into Europe and indication that UK might experience something a little more seasonal (i.e. some sort of northerly) past xmas day.
    [attachment=149121:GFS6-10day500mbHeightAnomaly.gif][attachment=149122:GFS11-15day500mbHeightAnomalyNH.gif]
    This is also supported by the NAEFS
    [attachment=149125:naefs-0-0-360.png]

    [b]Overall[/b]

    I expect the continuation of unsettled conditions, with on average temperatures remaining close to the norm. Given the expected continuation of a –NAO, and –AO I would not bet against colder interludes, in the form of brief northerlys, as we progress through the xmas period (something which has shown around xmas day on the latest model runs). I do not see great support for something prolonged this side of New Year. Given developments in the stratosphere I think the first half January, probably past week one, is when it could potentially come very interesting..!
  6. Mark Bayley
    [b]December outlook [/b]
    The following forecast is based on the latest stratospheric output, MJO, CFS, AO and NAO ensembles means, as well as 500hpa and 850hpa means.

    [b]Stratospheric outlook[/b]

    Stratospheric temperatures at both the 10hpa and 30hpa level are set to increase, as shown on the following diagrams. This should strain the vortex and encourage blocking.
    [attachment=146385:ECM current temp. conditions.gif][attachment=146388:ECM T240 temp. conditions.gif]
    The GFS also indicates a warming event. I note how the warming on the pacific side is extending into North America, pushing the coldest temperatures to the East of Greenland. This would support a large segment of the PV shifting into this region later in December, and lend support to a -NAO. It is important to note however that the troposphere and Stratosphere interactions seem to have been different this year, which would cast some doubt on this assumption. The extended cool period and higher zonal winds did not lead to strong and organised PV that some may have expected as we progressed through November. Why this occurred is beyond my knowledge.
    [attachment=146408:Warming forecast current GFS.gif][attachment=146409:Warming forecast T240 30hpa.gif]
    Mean zonal temperatures are forecast to decrease which again would strain the vortex and encourage blocking
    [attachment=146386:ECM current zonal conditions.gif][attachment=146389:ECM T240 zonal conditions.gif]
    I have limited understanding of waving breaking. I believe it stands for reflection of large-scale planetary waves off mountain chains that break into stratosphere, which in turn places pressure onto the vortex. If we use CH’s analogy of the balloon then it is perhaps simpler to understand how two wave breaks in the NH (placing pressure on two points of the vortex) can lead a split vortex, while one wave break (placing pressure at one point of the vortex) can lead to disruption,
    We can see from the ECM forecast that wave two activity is set to peak over the next few days, before petering out.
    [attachment=146390:ECM wave break T144 (2).gif][attachment=146392:ECM wave break T240 (2).gif]
    However, wave one is forecast to increase substantially at the day ten. So using the CH’s analogy, this should lead to further disruption (of an already disorganised) PV.
    [attachment=146391:ECM wave break T240 (1).gif]
    I should probably pass over the wave breaking section, I’ve only included it with the hope that one of the experts may correct me if any of my interpretation is wrong.

    The latest ECM geopotential height charts support higher pressure in the mid-atlantic with a NW west flow, as does the GFS. Based on these charts I would suggest height rises over Greenland are some way off (i.e. past day ten).
    [attachment=146393:Geo height 100hpa t240.gif][attachment=146398:GFS t240 geo height.gif]

    [b]MJO outlook [/b]

    The MJO signal is weak, with most models indicating that will remain in low amplitude. The UKMO seem keen on a weak phase one or two, the ECM on a weak phase one or eight while the GFS predicts a higher amplitude phase one (although briefly skirting through phase eight). Based on the forecasts I would have probably discounted the MJO. The GFS however has been keen on a higher amplitude phase one, and has for some days. The ECM would support phase one, albeit in much lower amplitude.
    [attachment=146407:UKMO MJO phase forecast.gif][attachment=146387:ECM MJO phase forecast.gif][attachment=146396:GFS MJO.gif]
    Phase one MJO would give us the following composite, heights over Greenland, and a trough over the UK. Note that these composites should only be used as a guide.
    [attachment=146383:DecemberPhase1500mb.gif]

    [b]CFS charts[/b]

    Not a model I normally use however the trend has been for higher heights in the mid-Atlantic and over Siberia for weeks one-two, with some support for higher pressure in these regions for weeks three-four. I should note there has been variability in these runs over the past week, although there is a theme for higher heights in the said areas.
    [attachment=146381:CFS outlook week 1-2.gif][attachment=146382:CFS outlook week 2-4.gif]
    The monthly CFS, for some time now, has indicated a below average December, with considerable blocking to our North.
    [attachment=146380:CFS heights forecast december.gif][attachment=146379:CFS global temp forecast december.gif]

    [b]AO and NAO Ensembles[/b]

    Both the GFS and ECM ensembles support a –NAO, after brief close to/positive spell, as we progress into and past the middle of December.
    [attachment=146384:ECM AO outlook.png][attachment=146397:GFS NAO forecast.png]
    The GFS also supports the general continuation of a -AO
    [attachment=146395:GFS AO Forecasrs.png]

    [b]Mean height ensembles[/b]

    The ECM ensembles are supportive of higher pressure in the mid-Atlantic, and over the Scandinavian region, lending support to some sort of easterly by day ten.
    [attachment=146399:Mean ECM T240.gif]
    The ECM 850hpa mean temperatures are shown to be below average.
    [attachment=146402:mean t850 ecm T240.gif]
    The GFS ensemble mean is also supportive showing higher pressure in the mid-atlantic retrogressing northeast.
    [attachment=146400:Mean height anoms t180.gif][attachment=146401:Mean height anoms t364.gif] [attachment=146404:Mean t850 t384.gif]
    Which is also supported by the NAEFS and NOAA
    [attachment=146405:NAEFS T198.png][attachment=146406:NAFES T364.png][attachment=146394:GEO height outlook next two weeks.gif]

    [b]Overall[/b]

    Overall im finding it rather difficult to produce a forecast, but then isn’t it always! What’s apparent is the PV shall remain disrupted and disorganised as we progress through December. I am generally supportive of height rises to the NE given the latest runs, although feel that these will transfer nearer Greenland as we progress through the month when we see further wave breaking disrupting the vortex and leading to more movement of the PV segments. This would also be supported by the GFS MJO outlook, and ensemble forecasts for the NAO from both the ECM and GFS. The CFS could also be included. Weatherwise a cold and unsettled start, with the potential for height rises to out NE, and some sort of easterly flow during the first third. As we progress into midmonth and beyond I feel higher pressure would transfer closer to Greenland, bringing a more N/NE’rly flow.
    I intend to update midmonth.
  7. Mark Bayley
    [b]Note: Next update either on Thursday or Sunday/Monday. All images below will/have change/d as they have only been hyper-linked, will attach them on the next update [/b]

    Thought it would be fun to have a go at a little longer range forecasting. I am by no means expert, however have learnt bits and bobs over last few years of my net-weather membership!

    I shall be basing my thoughts on the stratospheric output, MJO forecasts, long range ensemble forecasts and CFS weekly charts. Instead of writing a detailed explanation of how we interpret the stratospheric output, i shall instead refer you to the stratospheric thread in the winter section (see page one).

    [b]Stratospheric output[/b]
    (I made a recent post about this, so shall take it and adapt it a little)

    A rather positive outlook, for those looking for blocking (and something cold). Mean zonal winds are set to decrease at both the 10hpa and 30hpa level, which will strain the polar vortex (PV), as evidenced by the geopotential height charts posted later.
    [img]http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/fluxes.gif[/img]
    A warming at the 30hpa is also predicted, taking it above average, with the 10hpa not to far behind. Again this will only place strain on the PV, leading to disruption and fragmentation (and a -AO)
    [img]http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/temps.gif[/img]
    [color=#282828][font=helvetica, arial, sans-serif]Looking at the geopotential height charts we see a split in the vortex by day 10 at the 100hpa[/font][/color]
    [img]http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf100f240.gif[/img]
    [color=#282828][font=helvetica, arial, sans-serif]With sighs of splitting right up to the 10hpa level [/font][/color]
    [img]http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf10f240.gif[/img]
    [font=helvetica, arial, sans-serif][color=#282828]The GFS forecasts are of a simualr nature to the ECM, with a split in the PV at the 100hpa, and splitting as far up as the 10hpa level[/color][/font]
    [img]http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_z100_nh_f240.gif[/img][img]http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_z10_nh_f240.gif[/img]
    [b][font=helvetica, arial, sans-serif][color=#282828]MJO outlook [/color][/font][/b]
    [font=helvetica, arial, sans-serif][color=#282828]The ensemble forecasts for the MJO vary, the UKMO that was keen on a move to phase eight now suggests a low amplitude phase two, which suggests the following composite. Although given the low amplitude im uncertain what effect this would have. [/color][/font]
    [font=helvetica, arial, sans-serif][color=#282828][img]http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/UKME_phase_23m_full.gif[/img][/color][/font]
    [img]http://raleighwx.americanwx.com/MJO/DecemberPhase2500mb.gif[/img]
    [font=helvetica, arial, sans-serif][color=#282828]The GFS seems determined to drive the MJO into a higher amplitude phase eight, then one. Which would suggest the following composite.[/color][/font]
    [img]http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/NCPE_phase_21m_full.gif[/img][img]http://raleighwx.americanwx.com/MJO/DecemberPhase1500mb.gif[/img]
    [font=helvetica, arial, sans-serif][color=#282828]The ECM wants to drive the MJO through low amplitude phase one, two and three. [/color][/font]
    [img]http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_51m_full.gif[/img]
    [color=#282828][font=helvetica, arial, sans-serif]There seems great uncertainty in the MJO outlook, although on average from all the runs, i would probably suggest phase one seems more likely.[/font][/color]

    [b][color=#282828][font=helvetica, arial, sans-serif]CFS weekly [/font][/color][/b]
    [font=helvetica, arial, sans-serif][color=#282828]Not the most reliable charts but worth looking at none the less. Week one-two shows strong heights over Greenland, and lower heights to the south of us, which would lend support to a blocked and potentially cold start to December.[/color][/font]
    [img]http://origin.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk1.wk2_20121124.z500.gif[/img]
    [font=helvetica, arial, sans-serif][color=#282828]Week three to four also shows heights over Greenland, but shows lower heights by the 2nd half of the month [/color][/font]
    [img]http://origin.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk3.wk4_20121124.z500.gif[/img]
    [b][color=#282828][font=helvetica, arial, sans-serif]Ensemble[/font][/color]s [/b]
    [font=helvetica, arial, sans-serif][color=#282828]Will update this later[/color][/font]

    [font=helvetica, arial, sans-serif][color=#282828]Overall[/color][/font][color=#282828][font=helvetica, arial, sans-serif] [/font][/color]
    Based on the output, i would suggest a blocked start to December, with the PV disrupted and fragmented (and a -AO)[color=#282828][font=helvetica, arial, sans-serif]. I also see support for height rises around Greenland. Despite the models chopping and changing on whether the coldest air will get us, i would suggest at some point, over the next few weeks, that there is a high chance it would. [/font][/color]
  8. Mark Bayley
    Weather for the week ahead
    Monday (Confidence 80%)
    A cloudy wet start for, There maybe still some sleet and snow around for the hills in Wales and the peak district, As we move through the morning I expect any sleet or snow around to turn to rain apart from the highest peaks, Elsewhere it will remain cloudy with some light rain around, As we move into the afternoon I expect it to remain cloudy just about everywhere with maybe some light rain around in places. The far south however may see some sunny intervals as we end the day. Max temps will vary form Scotland 8c Wales 6c Northern Ireland 8c England 9c (perhaps 10c in the far south west)
    Tuesday (Confidence 70%)
    A cloudy start for most however northern England the south west and some places in the east may see some sunshine. There may be some light rain over central Wales for a time as well. As we move through the morning cloud will start to increaser from the south bringing with it some rain, in eastern Scotland the cloud should have cleared leaving a sunny morning. As we move into the afternoon though the cloud will continue to increase form the south bringing with it a band of rain that should push up north across the country throughout the afternoon. Max temps will vary from 8c in Scotland 6c in Wales 8c in Northern Ireland and 9c in England.
    Wednesday (Confidence 50%)
    A sunny start for those living in most parts England and Wales, Scotland northern Ireland parts of eastern England and Northern England will wake up to a cloudy morning. As we move through the morning cloud will clear from most areas apart from northern England Scotland and Ireland. There also maybe some light showers around as well. Going into the afternoon and the picture remains the same sunny in England and Wales while cloudy with some light rain around in Ireland and Scotland. Max temps will vary from 9c in Scotland 8c in Wales 8c in Northern Ireland and 11c in England.
    Thursday (Confidence 40%)
    A cloudy start for Scotland and Ireland, Elsewhere apart form the south west it will be a sunny start to the day. There maybe some light rain around in parts of the south west however its more likely to be light showers. Moving through the morning period there maybe some light snow for northern Scotland as cold air moves in Elsewhere it will remain sunny with some patchy cloud and showers in the south west. Moving into the afternoon light snow will continue in northern Scotland and will start moving slowly south. It will only be light and very patchy. Elsewhere it remains sunny with cloud and some showers in the south west. Max temps will vary from 5c in Scotland 7c in Wales 6c in Northern Ireland and 7c-8c in England.
    Friday (Confidence 30%)
    A cold start sunny start for many however there will be some patchy cloud. There may be some snow showers around as well especially in the east of the UK. As we move through the morning it will remain sunny for most however there will be a lot of cloud around giving one or two showers which may fall as snow just about anywhere however I expect mostly to be sleet or rain. Moving into the afternoon again sunny for most with some showers around which may be wintry. It will be a rather cold day with max temps varying from 5c in Scotland 6c in Wales 5c in Northern Ireland and 7c in England.
    Weekend (Confidence 20%)
    Saturday will see a band of rain crossing the UK perhaps falling as sleet on the leading edge. Into the evening and northern Ireland will see some sleet and snow. Sunday will see a cold start with some sleet and snow around across England and Wales however this will turn to rain later in the day. Feeling cold as well.
    Overall a wet week sunny at times perhaps Turing colder later on.
  9. Mark Bayley
    Heres my atempt at the week ahead useing the 12z gfs moddle on sunday
    Weather for the week ahead starting 4th of November. I create my forecast using the 12z GFS every Sunday afternoon . Overall I am pleased with my forecast last week. This week however is going to be very hard to predict and I might have to change it mid week. I have not included fog and frost in this forecast however will do shortly when I get my laptop back. Temp that I predict will be the max temps for the country
    Monday (Confidence 80%)
    A foggy start for people in the south however for people in the north a rather cloudy start to the day with some rain for people in northern Scotland. As we head through the morning the fog should slowly clear from most areas however may linger for a while. Cloud will push south bringing with it some patchy rain. As we move into the afternoon cloud will have moved in all over the south perhaps bringing some light showers with it. A different story for southern Scotland where it will be a rather sunny end to the day with some sunny intervals in the north of Scotland. Max Temp will vary form 11c in Scotland 11c in Northern Ireland 13c in Wales and 14c in England.
    :Special: Bonfire night 18:00 to 22:00 Patchy cloud for most and some clear spell in the northern England. So this bonfire should stay dry. Fingers crossed.
    Tuesday (Confidence 70%)
    A sunny start for apart from North Wales Northern Ireland and Northern Scotland where it will be cloudy. As we move through the day patchy cloud will move into Northern England else ware will remain sunny apart form Scotland Wales which will see some sunny intervals. Into the afternoon and the weather should remain generally the same. Some sunny intervals in Scotland and Wales with patchy cloud in northern England while else ware remains sunny. Temps will be cooler then they where on Monday. Scotland 10c, Northern Ireland 12c, Wales 10c and England 11c
    Wednesday (Confidence 60%)
    A cloudy start for all apart from those in the South West. As we move through the day cloud will persist in all areas however there may be the odd sunny interval. Western Scotland may see some sunshine for a time as well. Different story for those in the south west wall to wall sunshine. As we move in to the afternoon it will be pretty much the same cloudy every ware apart from the South West. Other areas though as I said before may see a few sunny intervals. Temps will vary from Scotland 12c, Northern Ireland 12c, Wales 13c and England 13c.
    Thursday (Confidence 40%)
    A cloudy start for all with maybe a few glimmers of sunshine in eastern Scotland. There maybe some patchy rain for a time in western Scotland. As we move through the day it will remain cloudy all over the UK with perhaps a few sunny intervals. Moving in to the afternoon and guess what. It remains cloudy with a few sunny intervals with some light rain in western Scotland. It will also be quite windy on Thursday as well. Especially in western Scotland where there may be gales for a time. Temps will vary from 10c in Scotland, Northern Ireland 11c, Wales 12c and England 14c.
    Friday (Confidence 20%)
    A sunny start for eastern areas however patchy cloud for the rest of the uk. There may be some light showers in Scotland as well falling as snow on higher ground. As we move through the day most areas will remain cloudy apart from Northern England and parts of the south west. There may be some showers around as well falling as snow on high ground in Scotland. Going into the afternoon most areas will become cloudy apart form from eastern England and again the south west. There may be some light sleet/snow showers over the hills in northern England for a time as well. There may also be some more snow showers over the Scottish hills as well. It will properly fee quite cold compared to of late. Temps will vary from Scotland 6c, Northern Ireland 9c, Wales 8c and England 10c. Temps might be a bit higher though in some areas.
    Weekend (10%)
    A mixed weekend. Cool/cold with showers for most perhaps wintry in nature for some. Quite cloudy as well
    Overall a mixed week with sunny spells and mailing cloudy. Maybe turning cold by the end of the week and into the weekend with snow showers for some.
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