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

[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 cold North and slowly strengthening NE flow will develop across the UK over the coming days as a ridge of High pressure moves into the NW later.

MODELS-2 WEEK HEADLINE Becoming slowly less cold with a lot of dry and bright weather away from some rain in the North later. Some frosts at night still chiefly in the South

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Forecast shows the UK lying on the cold side of the Jet flow currently but as High pressure builds over the UK the flow rides over the top of the UK meaning uppers rise and then continue in this form until later in the period..

GFS OPERATIONAL The GFS operational today shows a simple pattern which persists through the entire run with High pressure currently approaching the NW of the UK slipping further South towards Southern Britain by the weekend. It then meanders around the South and West of the UK for the remainder of the period. The current cold North or NE flow would be cutoff with time along with the  wintry showers across the SE and east until the weekend. Week 2 then looks dry and benign and somewhat less cold especially towards the North in NW winds here. The South would more likely continue rather cold with frosts at night but light winds and bright days.

THE GFS CONTROL  The GFS control run shows little significant differences in weather at the surface to the GFS operational with just small but subtle differences in the positioning of the High near or over the UK making local variances in the amounts of cloud and temperature levels the only major comparison day to day in the sustained High pressure pattern throughout.

THE GFS CLUSTERS The GFS Clusters show a 65% likelihood of High pressure near or to the SW of the UK in 14 days with benign conditions and temperatures just a little below average but with frosts by night in the South. The remaining 35% offer something rather more unsettled with stronger winds and rain at times.

UKMO UKMO this morning shows pressure building strongly over the UK in the next 5 or 6 days with a centre of High pressure well established near Southern Britain at the Day 6 period. The current North or NE flow will be cut off by the weekend removing the risk of wintry showers and turning things generally slowly less cold at least by day from the North.

THE FAX CHARTS The Fax Charts show little overall difference to the raw data with High pressure centred firmly near Ireland by Monday with a ridge from it across a large part of the UK drawing less cold air gently South across the UK.

GEM GEM today also shows High pressure dominating through it's run firstly cutting off the cold NE flow across the South by the weekend and then drawing less cold air from the North. then by next week a temporary spell of much stronger West winds over Scotland heightens the risk of rain here for a time before High pressure builds back North again later next week.

NAVGEM NAVGEM shows High pressure in total control of the UK weather for the foreseeable future as it builds a centre across the UK by the weekend with fine and dry weather for all with temperatures somewhat less cold but still very frosty at night in places under very light winds.

ECM ECM this morning shows total support for the same general theme of High pressure over or to the West of the UK with benign and dry conditions developing following the rest of the working week being cold and breezy with some wintry showers near the South and SE. Next week sees calm weather with temperatures somewhat higher by day but with still night frosts before the High is show to slip slowly South out of the UK by the end of the run bringing much milder and stronger Westerly winds down from the North later with rain in the far North.

ECM 10 DAY MEAN The 10 Day Mean this morning indicates the most likely position we will be in at the end of Day 10 will be one of High pressure close to Southern Britain with a Westerly flow to the North maintaining a lot of dry weather with any rain in the far North. Temperatures should recover away from Southern England where Anticyclonic conditions may maintain rather cold weather here with frost at night.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend towards somewhat less cold but Anticyclonic conditions remains through all the output this morning with a higher than average level of support between all the output.

MY THOUGHTS High pressure is the main feature shown within all the model output near to the UK and maintaining a lot of dry and bright weather for the coming two weeks. The current cold pool of air across the UK is scheduled to decline over the end of the week but this process is likely to take a long time to reach the extreme South. However reach us it will and as uppers rise we will then rely on surface cold to develop under still conditions under the High pressure from the weekend on and this looks most likely across the South. From that time it looks like the North will see a strengthening of a West and NW flow carrying a lot of cloud in from the nearby Atlantic suppressing brightness and preventing frosts and this may well eek into the South at times too. So after the wintry showers of the rest of this working week any significant precipitation will be of rain and restricted to the far North late in the period with many places staying dry for a week or two from now. Then as I look into the far reaches of the output I can see two things. One, it looks unlikely that we will find ourselves falling into notable cold again soon as High pressure locates close to but unfavourably  likely to be South or SW of the UK maintaining a feed of air from the West and NW across the UK. Secondly it looks like staying largely dry for the first two weeks of February with many places seeing very little if any rain through the entire 15 days of this morning's model output providing they verify of course. So as has been the case all Winter we return to nomansland in the longer term with little desire to rise pressure North of the UK and sustaining the fact that we will continue to have to look towards the North for any cold to return later in the month rather than from the East.

Issued at 08:00 Tuesday February 3rd 2015

[knocker]

Last nights NOAA is sticking to HP domination with a slack SW flow to the north.

 

This morning's GEFs and ECM are plugging the same with some differences. The GEFs has trough NE N. America and the ECM a weak trough eastern Atlantic which on the ext EPS is not significant apart from maybe increasing the strength of the zonal flow.

Chart courtesy weatherbell

 

[JOPRO]

February 1991 keeps cropping up in my mind, didn't that cold spell start from a UK High at the end of January that drifted over to Scandi? Not certain maybe some of the more knowledgeable members could look this up. But surely having high pressure over the UK gives it a chance of drifting East or North west? Or worse case of you are a cold lover this time of year south? Its going to go somewhere after the uk so what is the form horse?

[seaside 60]

Always the same scenario, down here in the south east after a cool/cold spell for most of the country the models show less cool/cold weather as mentioned by many on here.

However I bet that the temps down here will actually stay the same or get colder,

The temps have been modeled/promised far to low, I would suggest it would be colder down here after the next weekend.
 

[liam300]

Always the same scenario, down here in the south east after a cool/cold spell for most of the country the models show less cool/cold weather as mentioned by many on here.

However I bet that the temps down here will actually stay the same or get colder,

The temps have been modeled/promised far to low, I would suggest it would be colder down here after the next weekend.

 

 

What gives you this perception?

[seaside 60]

What gives you this perception?

It an observation for this little corner, built on years of weather.

It works the same in spring, the models cant work out local areas.

Anyways that the reason and its going OT.

[mushymanrob]

well i like anticyclonic gloom at this time of the year.... its dry and calm, useable outdoor weather for working in. so its not looking like my prefered mobile mild southwesterly february, but my second fav, dry and calm, but without overnight frosts.

i note that several others are now expecting a gloomy dirty high this morning, so im no longer alone in expecting that option given the current expected position of the high.

the anomaly charts suggest the high will sink to a more southern latitude, thus adding support to the current ops which also suggest itll do that over time. IF this does happen, then imho theres little chance for a decent cold spell to evolve, but not impossible.

 

[Captain Shortwave]

well i like anticyclonic gloom at this time of the year.... its dry and calm, useable outdoor weather for working in. so its not looking like my prefered mobile mild southwesterly february, but my second fav, dry and calm, but without overnight frosts.

i note that several others are now expecting a gloomy dirty high this morning, so im no longer alone in expecting that option given the current expected position of the high.

the anomaly charts suggest the high will sink to a more southern latitude, thus adding support to the current ops which also suggest itll do that over time. IF this does happen, then imho theres little chance for a decent cold spell to evolve, but not impossible.

 

610day.03.gif 814day.03.gif

I think how sunny the high will be will be quite dependent on how the end of the week pans out and how much cloud gets trapped with decaying fronts and possible low cloud. The position of the high on the GFS and UKMO doesn't look too bad (the GFS shows widespread night frosts so there might well be some clears skies in here).

I may be wrong there, but it is unusual to see such a strong high build over the UK (>1045mb).

As an aside considering the GFS vs Euros debate, the GFS does from experience have an edge on these UK high scenarios, for example the July 2013 dry spell was modelled better on the GFS than the ECM or UKMO, the latter two wanted to retrogress the high into the Atlantic on a couple of occasions which simply didn't occur and hence the weather was dry and very warm/hot (except for transient periods near the east coast).

GFS 06z showing the Margaret Thatcher of high pressure systems again, ruling with an iron fist.

 

Wow the surface pressure rises above 1030mb on Friday and remains above 1030mb for the rest of the run (including low resolution... jeez  )

Edited February 3, 2015 by Captain shortwave

[mulzy]

No point sugar coating the NWP output this morning - little chance of sustained wintry weather in the medium term.  Things can change, but for now enjoy the snow if you have any because it could be the last you see this winter.

 

Edited February 3, 2015 by mulzy

[Jason M]

Once in place the UK high remains pretty much in situ for the entire run. Sadly quite a common set up at this time of year.

 

Of course a couple of weeks back we had 100% agreement for zonality and we got a cold spell instead (well 'rather cold' anyway). Hopefully something will change, but the clock is now ticking ever more loudly.

 

Other than the 06Z on Sunday, GFS has been rock solid on this and on this occasion it looks like its wiped the floor with the other models.

[Ali1977]

That is one of the most boring runs from the GFS I've seen.  Hopefully its a sunny high with some hard frosts.

[I remember Atlantic 252]

That is one of the most boring runs from the GFS I've seen.  Hopefully its a sunny high with some hard frosts.

 

way better than last Feb's runs, they were most boring to me, floods, severe gales, raging zonality

[Summer Sun]

Its going to be very quiet in here whilst GFS produces charts like below

 

This Friday

 

 

1 week later

 

 

6 days later (Feb 19th)

 

 

It could be a very stubborn high to shift

 

An exceptionally dry first half of February looks a decent bet at this stage

 

Edited February 3, 2015 by Summer Sun

[johnholmes]

No point sugar coating the NWP output this morning - little chance of sustained wintry weather in the medium term.  Things can change, but for now enjoy the snow if you have any because it could be the last you see this winter.

 

 

True enough on that chart and this type does give a more balanced view of how the pattern may evolve.

However, folk wrote of December/winter in early December.Here it snowed on 2 days with lying snow at 9am on 2 days.

Some then wrote of January/winter in early January. After a pretty mild first half the second half returned 3.3C as a mean and 6 days with snow falling and 4 with it lying (covering more than 50% of the ground) at 9am on 4 mornings.

Writing off February now and it has snowed this morning with just under 1cm it may snow again later and overnight which would already be 2 days of snow?

Dangerous game writing off winter with knee jerk reactions, much as writing of summer with similar ideas!

Edited February 3, 2015 by johnholmes

[sunnijim]

Gloomy high or sunny High? One thing is certain it will take some shifting.Where will it drift to,well the favoured spot would be back toward the azores allowing a westerly zonality after mid month.

Our problem throughout this winter as far as a decent freeze has been concerned has been the strong azores High,its movement at times has at least allowed a few Northwesterly incursions with snowfall to a favoured few.

The next most likely imo is for it to sink SE into mainland Europe.Options of it heading west or Northwest as shown by 06z gfs on Sunday seem unlikely now as a weakning High (after mid month) would favor a 'quiter' route of departure.

Hooking up with a Scandi High longer term,or our own High heading that way as in 1991 I'm keeping my fingers crossed.

Edited February 3, 2015 by sunnijim

[chionomaniac]

Well we have all heard about the Bartlett slug - well according to the GFS today, I think that we are seeing the birth of the UK snail....

[knocker]

Looking at the ECM32 there seems little  of any major change into March with the  trop vortex over Hudson. Perhaps less emphasis on a static high and a more zonal flow but there is the usual tendency to do this at extended ranges anyway..

[johnholmes]

Nothing on the 500mb anomaly charts, the 3 I use, to suggest any deep cold returning in the 10-15 day time scale. That is not to say things may not change in that period.

Can the MJO help?

The current chart on GFS shows it in almost zero centre phase 6. That 500mb equivalent chart, if it applies at all, does not show the pattern we have at the moment. Not unusual when it has little distance from zero.

The prediction on the same model is for it to move, again almost around the origin to 7 or 8. Being that close to the origin is usually a signal for no help for cold from the MJO.

So where does that leave us with data to look at for the 8-15 day or longer time scale? Not much it has to be said, so maybe someone with more knowledge for longer term 'drivers' can help out?

But this winter is not a 'normal' one for sure. It seems to have had the ability to 'conjure' cold spells out of not much so maybe it can do it again before the end of meteorological winter. Then of course we know that March can provide pretty cold conditions in spite of increasing sun and warmth-think 2013 for many areas. 3 weeks after it supposedly finished a walking party I led still drove through 10-15cm of snow by the roadside on the way to the HF hotel near Dolgellau and we could not walk on Cader Idris due to snow and ice down to about 800ft, so for cold lovers the search for more cold and snow is not yet over in my view.

Edited February 3, 2015 by johnholmes

[Alexis]

Could well end up in the top 10 driest Februaries this year going by the models.

[chionomaniac]

Looking at the ECM32 there seems little  of any major change into March with the  trop vortex over Hudson. Perhaps less emphasis on a static high and a more zonal flow but there is the usual tendency to do this at extended ranges anyway..

What the snail isn't crawling to Scandi? Look East Man!

 

(https://twitter.com/MattHugo81/status/562582743826309120)

[Jason M]

Could well end up in the top 10 driest Februaries this year going by the models.

 

Could do, but I recall looking at a few sets of charts similar to this in mid December 2013. Its fair to say that what transpired over the second half of December that year didn't break any records for dryness :-)

 

It looks grim at present and the GEFS from the 06Z run don't bring much cheer either. That said, I've seen quite a few similar situations modelled over the years and quite often this type of set up can be the forerunner of a major pattern change. In that context Chio's post was interesting.

Edited February 3, 2015 by Jason M

[knocker]

What the snail isn't crawling to Scandi? Look East Man!

 

(https://twitter.com/MattHugo81/status/562582743826309120)

 

Well i only have access to the broad brush output but yes it does show HP to the east but looks transitory. On the 21st for example it does have HP to the east but the main feature is the Greenland trough orientated SE which on the surface translates to a low Denmark strait bringing SW/W winds to the UK. I can't see much blocking there but I will obviously bow to MHs greater expertise although I did say less emphasis on the static high. Look North West Man!

Edited February 3, 2015 by knocker

[492]

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

8-10 day 500mb charts continue with the theme of low heights to the south with one lobe of the trough over the eastern Med and another close to the Azores. The ridge to the north is flatter, slightly further south being squeezed between low height to the north and the low heights to the south. 06Z GFS shows the surface high meandering in the vicinity of the UK and western Europe which could give frosty nights with potential for freezing fog and inversion cold. At the same time western Europe is expected to slide into the freezer especially if it manages to catch more of a snow cover over the next few days and a drift from the continent could be decidely cold. 2.5 CM of snow here this morning and still on the hills so feeling optimistic. 

[mushymanrob]

 

However, folk wrote of December/winter in early December.Here it snowed on 2 days with lying snow at 9am on 2 days.

Some then wrote of January/winter in early January. After a pretty mild first half the second half returned 3.3C as a mean and 6 days with snow falling and 4 with it lying (covering more than 50% of the ground) at 9am on 4 mornings.

Writing off February now and it has snowed this morning with just under 1cm it may snow again later and overnight which would already be 2 days of snow?

Dangerous game writing off winter with knee jerk reactions, much as writing of summer with similar ideas!

 

i dont think anyones 'writing off winter' john, just saying that the current expected synoptical pattern isnt one thatll be likely to lead to a deep cold spell as you ...

 

Nothing on the 500mb anomaly charts, the 3 I use, to suggest any deep cold returning in the 10-15 day time scale. That is not to say things may not change in that period.

 

.... go on to say. (15 days time = 18th feb, just 10 days left of winter)

as i see it, its about probability , not certainty, and i believe the scales are tipped against a deep cold going off current outputs which might change as you say.

[EML Network]

One word can sum up the next 10 days and quite possibly more..

 

DRY