Model Output Discussion - 1st February Onwards 12z--->

[bluearmy]

The Azores ridge too Far East to allow the mean trough to back far enough west for the uk to avoid the 'warm' phases. 'Mobile topplers' might be the relevant phrase for us. Upstream cold keeping the pm air masses colder than we might expect and any troughs in the flow might bring the odd surprise to lower ground in the north of the uk.

as we head towards march, I always feel a continental feed is essential for snowfall in the southern half. A north or norwester going to be of little help.

wonder what the ECM weeklies has in mind?

[knocker]

The Azores ridge too Far East to allow the mean trough to back far enough west for the uk to avoid the 'warm' phases. 'Mobile topplers' might be the relevant phrase for us. Upstream cold keeping the pm air masses colder than we might expect and any troughs in the flow might bring the odd surprise to lower ground in the north of the uk.

as we head towards march, I always feel a continental feed is essential for snowfall in the southern half. A north or norwester going to be of little help.

wonder what the ECM weeklies has in mind?

 

Well presumably you have had a look?

[Captain Shortwave]

Milder than next week,when there will be snow showers for many in the North.Frequent polar incursions shown by the 00z GFS out to the end.Let's see what ECM says as UKMO has a cold feed by next Monday/Tuesday too.

Snow isn't the first thing that comes to mind when I see the day 6 UKMO

More like heavy rain and widespread gales/severe gales.

 

There is a chance over the coming weekend that the north east of the UK as a brief northerly sets up

 

Potential wise, this is probably the coldest event I could find and even then it could petter out. 

[bluearmy]

Well presumably you have had a look?

Have now - inconclusive. More of the same out to mid week 3 where a slow transition to less w European high anomolys takes place. We are on the edge of the nw/se flow when it occurs.

thereafter, signs that Greenland goes less cold and Europe becomes colder. as I said, unconvincing at the moment but within the variances chucked out each run of the model, no sign of an early European spring.

[IDO]

It is hard to get excited by the upcoming 10 days. All models in agreement for a mobile alternating PM to TM flow with the south having mild interludes between the colder flows. This pattern for the south usually modifies the uppers to around -5c in the PM bursts and that nearly always coincides with the drier baby ridge(s) moving through:

 

 

Looking at the next 12 days I don't see widespread snow for any part of lowland England, though showers to the NW and W once the rainy cold front(s) run through. These had been showing snow a few runs back so the trend is to modify that westerly flow with time. Scotland should see some of the white stuff though, and of course those mountains and hills in the north possibly. Into FI again and a snow event on the GFS op (20% support for the south) is showing up (D14) but usual caveats apply at that range.

 

The NH profile suggests the PV is defying the usual prognosis and becoming more organised as the mean shows:

 

 

Not what I was expecting so wary of that outcome at the moment. 

[knocker]

Have now - inconclusive. More of the same out to mid week 3 where a slow transition to less w European high anomolys takes place. We are on the edge of the nw/se flow when it occurs.

thereafter, signs that Greenland goes less cold and Europe becomes colder. as I said, unconvincing at the moment but within the variances chucked out each run of the model, no sign of an early European spring.

 

Probably fair enough. More dominant Azores HP week three than week four with temps around average. All fairly nondescript really.

[winterof79]

ECM and UKMO at 144z have a better looking rush of w/n/w than the GFS 

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS.

THE CURRENT GENERAL SITUATION A ridge of High pressure across Southern Britain will persist wit a strengthening and milder SW flow developing across the NW.

http://www.wetterzentrale.de/pics/Rtavn001.gif

MODELS-2 WEEK HEADLINE Changeable and very windy weather seems likely especially with strong winds and heavy rain for all areas at times. Near average temperatures but rather cold at times in the North.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble Forecast shows a strong flow later this week directed South across the UK and then setting up a position West to East across a more Southerly latitude than of late close to Southern Britain or further South still..

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS operational today shows deeply unsettled weather affecting the UK from later this week as the current rather changeable pattern caused by the occasional passage of troughs gives way to windy and often rather cold conditions with showers or longer spells of rain and snow on the hills as deep Low pressure areas and troughs become much more active and pass much closer to the North of the UK with gales or severe gale West or NW winds at times, this regime continuing well into March.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif
 
THE GFS CONTROL The GFS control run shows very little deviance from the theme set by the operational run with just the caveat that High pressure may be a little closer to the South at times but making very little overall difference to the weather expected in the way of rainfall and wind strengths as the pressure gradient across the UK remains large.

THE GFS CLUSTERS The GFS Clusters today still show an 85% cluster in support of a broad westerly flow blowing across the UK with wet and windy weather alternating with showers as a result. The 15% show High pressure further North into Southern Britain with the unsettled and windy weather with rain restricted to Northern areas.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

UKMO UKMO this morning shows very unsettled weather developing later in the week with a very deep depression to the NW by the start of next week with severe Westerly gales, bands of heavy rain and wintry showers all featuring across the UK by then.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts this morning show a couple of quieter days before a steepening of the pressure gradient is shown across the UK and a complex series of troughs and areas of rain cross England and Wales later in the week and followed by a brief cold Northerly flow on Saturday.

http://www.weathercharts.org/ukmomslp.htm#t120.

GEM GEM also shows a very mobile and aggressive Westerly flow across the UK in the coming 10 days with rain, heavy at times along with Westerly gales alternating with short periods of colder weather with wintry showers at times.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM too shows pressure falling more substantially over the UK by the end of the week onward with deep depressions and strong Westerly winds delivering spells of wet and very windy weather with severe gales with wintry showers and colder weather in between.

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

ECM ECM is broadly similar in type to all the above in as much as it is going to become windy later in the week and more especially next week. There will continue to be a mix of rain and showers at times as successive troughs run East over the UK in the strong Westerly flow later. There will be gale or severe gale winds at times and it will no doubt be cold enough at times for wintry showers to fall over the hills.

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN The 10 Day Mean this morning shows the Azores High at it's home base while a Low pressure belt lies between Scandinavia and Southern Greenland with West or NW winds dominant across the UK with rain or wintry showers for all.

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models continue to all agree on a shift towards a deeper unsettled period with strong winds and rain or showers in a pattern of Low to the North and High well to the South and SW of the UK.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.4 pts followed by UKM at 96.9 pts and GFS at 96.1. At 5 days ECM just about leads the field at 89.3 pts over UKMO at 88.4 pts and GFS at 86.2. At 8 days ECM remains the leader with 62.0 pts over GFS's 59.5 pts. Then at Day 10 ECM retains superiority at 44.9 pts over GFS at 41.5.

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig
 

MY THOUGHTS It now looks very likely that the weather is going to turn very disturbed from the end of this week. The pressure gradient is likely to steepen sharply North to South by the end of the week and weekend with strong winds from between SW and North alternating as each trough passes through. Then over next week a real powerhouse of a Westerly flow looks likely with severe gales with damaging gusts possible in places coupled with spells of heavy rain and colder weather with squally wintry showers in between. The Jet flow responsible will of moved well South than lately maintaining the presence of this weather type throughout the remainder of the period and possibly well into March. All models and ensembles largely support for this theory so we can accept that the above pattern is issued with a higher level of confidence than average. Frost and fog is likely to occur with less than average frequency given the wind strengths and snowfall although prominent under colder polar maritime interludes possible anywhere will only be a transient feature before the next system rushes in. So all in all a change from the benign conditions of late to much more fast changing and volatile weather conditions with March winds probably living up to its name as we move towards Meteorological Spring.  

Issued at 08:30 Tuesday February 17th 2015

[Interitus]

Going on recent GFS runs it seems strange to be considering anything other than an extremely mobile pattern in the next couple of weeks, and for the NH as a whole. The AO forecast is through the roof, with a mean getting on towards 4.

 

 

For perspective an AO of 3 is in the top 1.67%

3.5 is in top 0.83%

4 would be in top 0.36% with only 85 days out of 23772 since January 1950 having a higher AO.

 

Beyond 7-days naturally the uncertainty increases but there are a number of the ensemble which approach the top 15 with an AO of 5 and indeed the record of 5.911 almost 25 years to the day since it it was recorded on 26/02/1990.

Edited to prevent image updating!

Edited February 18, 2015 by Interitus

[Mucka]

This mornings GFS looks unlikely to verify as far as Southerly extent of any troughs over UK, far shallower than the Euros with the Azores ridge much more influential but also it is flatter than the majority of its ensembles.

144 comparison UKMO GFS (ECM is somewhere in between)

 

[Ali1977]

Interesting post from Ian F on the SW England thread - poss blocking in March with the EC showing some high pressures to the west, and Glosea showing signs of highs to the NE...Shame it's only showing now, however we all know March can deliver if the set up is correct. These are only signs though, and way way in FI.

[Frosty.]

Lots of opportunities for snow on the Gfs 00z, especially for northern Britain, quite wintry at times in what looks like an extremely unsettled outlook.

[bluearmy]

Probably fair enough. More dominant Azores HP week three than week four with temps around average. All fairly nondescript really.

That week 3 and 4 mean does allow for wintry clusters though knocker. It doesn't seem to allow for particularly springlike ones.

[Summer Sun]

After a fairly clam month the final week of winter looks like starting on more unsettled note with some strong wind gusts around for large parts of the UK

 

Edited February 17, 2015 by Summer Sun

[knocker]

That week 3 and 4 mean does allow for wintry clusters though knocker. It doesn't seem to allow for particularly springlike ones.

 

Agreed. Although I have to say I'm looking for less wintry conditions in these parts

[Frosty.]

That week 3 and 4 mean does allow for wintry clusters though knocker. It doesn't seem to allow for particularly springlike ones.

It looks like Scotland will have plenty of wintry clusters during the next few weeks, I'm sure the mountain resorts will do very well, lots of snow on the way.

Edited February 17, 2015 by Frosty.

[mulzy]

Going on recent GFS runs it seems strange to be considering anything other than an extremely mobile pattern in the next couple of weeks, and for the NH as a whole. The AO forecast is through the roof, with a mean getting on towards 4.

 

 

For perspective an AO of 3 is in the top 1.67%

3.5 is in top 0.83%

4 would be in top 0.36% with only 85 days out of 23772 since January 1950 having a higher AO.

 

Beyond 7-days naturally the uncertainty increases but there are a number of the ensemble which approach the top 15 with an AO of 5 and indeed the record of 5.911 almost 25 years to the day since it it was recorded on 26/02/1990.

 

The winter AO to date and that AO forecast for the next 2 weeks puts the final dagger into the heart of the OPI and many winter forecasts including mine.  The long range Met Office forecast and the Glosea5 model has come out of this winter with a lot of credibility.  Hats off to them...

 

As others have eluded to, PM spells just don;t cut it for most of southern Britain, even in the height of Winter let alone late Feb/early March (e.g. in London we have -4 uppers right now but temperatures could be as high as 10C today).

[mushymanrob]

The outlook is totally uninspiring, with the azores high unfavorably positioned (by the end of the week and beyond) for any early spring warmth or any last chance cold. whilst its currently looking like there will be more pm incursions then tm, westerly winds with wind and rain / colder showery doesnt really inspire much conversation. some might see snowshowers, particually 'up norf' with elevation, the rest of us are in abit of a 'no mans land' waiting for spring to start properly.

Edited February 17, 2015 by Polar Maritime
To move discussion on..

[Frosty.]

Nothing exciting unless you live on a scottish mountain or like cold rain and sleet down your back...

Bring on spring!

It looks snowy at times in Scotland and not just on the mountains. Edited February 17, 2015 by Frosty.

[Frosty.]

The Gfs 06z shows lots of cold, snowy and icy weather across scotland and n.ireland as they are frequently within a polar maritime airmass, the snow risk is mainly at elevation but sometimes down to sea level in the north, the snow risk also extends down to Cumbria and even as far south as n.Wales and the pennines but the main risk is for scotland. Mild sectors are very brief across northern UK according to this run. In between all the wintry showers it looks very wet and very windy at times, however, occasional brief atlantic ridges push east with widespread frosts depending on timing.

Edited February 17, 2015 by Frosty.

[Daniel*]

On holiday but for the South it may be any rain reverts to snow overnight of course there will be little or none accumulations. For Scotland eesh it's looking more like a cold spell.

Edited February 17, 2015 by Daniel*

[johnholmes]

Interesting post from Ian F on the SW England thread - poss blocking in March with the EC showing some high pressures to the west, and Glosea showing signs of highs to the NE...Shame it's only showing now, however we all know March can deliver if the set up is correct. These are only signs though, and way way in FI.

 

And note that Met themselves, once again, do not indicate anything like this 'possible' outlier. So the professionals see this as just what it is an outlier for the time being and not enough to warrant any mention.

[legritter]

Good afternoon all ,very quiet on here and i can understand why there are only a few posters around ,very nice winters day and plenty of  other interests to keep us busy .looking at todays charts things could get interesting come later this week and the possibility of some colder weather turning up next week as low pressure systems move across the UK or come very close .Not every ones cup of tea but if the Dice falls right some Happy posters .Its been a long frustrating winter for most this year if you are craving for lowland snow but we have to accept that Pressure patterns have not been in our favour ,its a hard one to swallow but eventually things will change in our favour When well thats what makes the chase interesting ,heres hoping we can squeeze some snowy synoptics out the next month then all enjoy a good summer and fingers crossed the patterns are in our favour next time .Brilliant forum and a great place to increase our knowledge ,  

[Gael_Force]

And note that Met themselves, once again, do not indicate anything like this 'possible' outlier. So the professionals see this as just what it is an outlier for the time being and not enough to warrant any mention.

 

I might be misunderstanding you but Mr F does not mention outliers: the two medium range models they rely on are at odds with one another. As far as I've read over the winter they have been showing pretty consistent signals until recently so this departure may be a sign of change in weather regime?

 

I note the switch in the Met Office long ranger - January was a low heights scenario for Spring whereas latest update is very high pressure dominated. They don't usually change as much, month to month, so maybe background signals are complicated or muted.

[sunnijim]

I might be misunderstanding you but Mr F does not mention outliers: the two medium range models they rely on are at odds with one another. As far as I've read over the winter they have been showing pretty consistent signals until recently so this departure may be a sign of change in weather regime?

 

I note the switch in the Met Office long ranger - January was a low heights scenario for Spring whereas latest update is very high pressure dominated. They don't usually change as much, month to month, so maybe background signals are complicated or muted.

Well lets hope the signal for a block is the Azores high really getting its act together,rather than the flirtations with us throughout winter 14/15.

Cold chasing in March? Harking back to the exceptional uppers that produced the early March cold and snow in 2013 ( very rare) is not a justification for me to hanker after what would most likely end up as the same marginal dross that most of us have been subjected to all winter.

Roll on Spring days and warm sunshine.