Model output discussion - 20th Feb onwards

[KyleHenry]

First phase of the pattern change to cold begins Within 48hours.

There is much, much more to come as the models slowly react to the Trop/Strat coupling. Models can't get a hold of the vast changes coming to fruition but the signs are starting to show in FI. 

We should within the next 5-7 days start to see the real potential coming our way. That should start shortly after the 5th  March and weeks following by displaying deep penetrating WAAs into polar region. Especially one through Greenland to give us a -NAO. 

Some may say it's too late but the cold air is there and is about to be unlocked.

 

Just as I say that the ECM at 240z shows the potential.

Edited February 23, 2016 by KyleHenry

[knocker]

This morning's ecm also showing a colder than average dry week ahead with the depression(s) on Friday and Saturday skirting the SW. It retains the probability of wintry showers in the east.

[Ali1977]

20 minutes ago, knocker said:

This morning's ecm also showing a colder than average dry week ahead with the depression(s) on Friday and Saturday skirting the SW. It retains the probability of wintry showers in the east.

Not sure on the chances of it, however if that weather system to the SW makes it far enough inland, this could fall as Snow. The shape of it could also mean something quite prolonged, nothing seems to point that way but you never know.

[knocker]

Well as we are talking 'potential' this morning the GEFS 10-15 anomaly is no different to the NOAA, GEFS and ecm of last night with a coldish NW flow sourced in Canada prevailing with the continuation of periods of unsettled weather and temps a little below average. I can see little sign of deep cold and a plunge into the deep freeze but that could change with the sudden appearance of a torpedo of course.

[Singularity]

It's a real shame we see that Icelandic shortwave (another one!) looking to prevent trough disruption and sliding low action occurring soon enough to keep the continental type cold pool in place beyond Mon or early Tue as it means we have to redevelop the cold air again after LP has dived back south into Europe.

Still a theoretical chance that things won't play out that way early next week, but there aren't any clusters in the GEFS that go that away any more.

 

I do like the way ECM has a general move of deeper cold air in our direction from well E/NE of us in the latter stages, but we could do with the storm over Svalbard being less intense as that would reduce the mixing out of cold air before it even reaches us. 

I'd like to thing we're poised to see a classic 'upgrading period' in terms of the extent and strength of high latitude blocking in the models, as the MJO and stratospheric forcing comes through.  This seems the more likely escape route from cold rain than a return to mild conditions.

Speaking of the MJO;

Not convinced about that sudden stall and slow decline from ECMF. Usually some eastward momentum is maintained until the MJO is within about 1 sd of the COD. Perhaps an ECMF/GEFS blend.

Ironic that GEFS has the better move into phase 8 yet continues to retain too much momentum across the U.S./Canada.

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON TUESDAY FEB 23RD 2016

THE CURRENT GENERAL SITUATION   A cold but slack North to NW flow is blowing across the UK over the next 24-48hrs with showers near Northern, Eastern and later Western coasts.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK lies between 2000-4000ft today North to South. Mostly dry weather for many with some wintry showers on the Scottish Mountains exposed to the North.

http://www.snow-forecast.com/maps/dynamic/uk

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif

MODELS-2 WEEK HEADLINE  Some rain or showers at times with snow over hills. Temperatures mostly near or somewhat below average.

THE GFS JET STREAM FORECAST  The Jet Stream is looking like it will slip sharply South of the UK over the coming few days before it slowly migrates back north for a time and then settles on a NW to SE course either down across the UK or to the South and West by the end of the period.

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

GFS OPERATIONAL The GFS Operational Run today shows a lot of rather cold weather across the UK over the next few weeks. The weather on the ground will be changeable and although a lot of dry and benign weather with frosts at night occurs Low pressure sliding down to the South of the UK later this week and over the weekend could bring the threat of rain, sleet and hill snow for a time before High pressure pushes fine and frosty weather South across the UK for a time followed by stronger West then NW winds and a rinse and repeat type return to cold NE'lies later with further chances of rain and hill sleet or snow with further night frosts in places well into March.

GFS CONTROL RUN The Control Run today shows the pattern above with the only caveat shown being the better recovery of temperatures in Week 2 as a more mobile based Westerly pattern establishes with rain and showers at times in average temperatures most prolific towards the North and West.

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

http://www.wetterzentrale.de/pics/Rtavn3841.gif

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=144&mode=0&carte=0

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=384&mode=0&carte=0

GFS ENSEMBLE DAY 14 DATA  The GFS Clusters today paint a very unsure outcome in two weeks time with a 50% group showing High pressure having overall control of the UK weather at that point positioned either across or just to the South of the UK whereas the remaining 50% support more Atlantic based weather under Low pressure over or to the North of the UK with rain or showers at times wintry on Northern hills. 

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 The UKMO model this morning shows slack winds for the UK over the next few days with rather cold but mostly dry weather away from windward coasts where wintry showers occur. Later in the week the slack pressure gives way to a raw SE, East and then NE wind as Low pressure slips SE to the SW of the UK with the threat of dull and raw weather in the South with some rain or sleet for a time before a ridge of High pressure slips South over the UK towards the start of next week with fine and frosty weather looking likely for many by that time.

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

THE FAX CHARTS The Fax Charts today shows a similar pattern to that supplied by the above raw data with a simplistic slack pattern gradually complicated by Low pressure sliding South to the SW of the UK late this week. It seems that any threat of precipitation from this is looking more and more likely to affect just far Southern and Western parts where it is conceivable a little sleet or snow could fall over the hills and moors there for a time but northern and eastern extent of this looks increasingly very limited.

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

GEM GEM today shows the same well worn pattern of rather cold weather with a keen east wind developing across the South later this week before winds back to the West and NW with rather cold and changeable weather developing next week with rain and showers for many and sleet or snow over the hills.

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

NAVGEM NAVGEM also takes Low pressure South to the SW of the UK later this week before it moves away East over Southern Europe backing winds from a chilly SE point through East and NE through the early days of next week with perhaps some wintry showers in the SE for a time. Then a weak ridge collapsing SE over the UK with fine and frosty weather for a short while before Atlantic West or NW winds develop and bring changeable and still rather cold weather to all parts by midweek next week. 

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

ECM ECM this morning follows the theme of the rest with Low pressure sliding South into Biscay later this week and then exiting it away east over Europe filling as it goes. It's effects will be limited for the UK with an increase in the East wind at the end of the weekend the most noticeable feature rather than precipitation. The winds then back 180 degrees towards the West with wet and windy weather spreading across all areas next week followed by a cold North to NW flow with wintry showers later next week as a deep low pressure area lies to the NE of the UK by that time.

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

ECM 10 DAY MEAN The 10 day mean chart continues to suggest chilly NW winds across the UK in 10 days time with showers or longer spells of rain, sleet or snow under the influence of Low pressure over the North Sea and High pressure well to the SW and a Jet Stream well to the South and West of the UK too.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The theme remains for a rather cold couple of weeks with a lot of dry weather to begin with before more unsettled conditions developing later in the period in a cold NW flow.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with UKMO at 99.5 pts and GFS at 99.4 pts.  At 3 days ECM is leading with 97.7 pts to UKMO's 97.2 pts while GFS lags behind at 96.5 pts. At 5 days ECM leads with 91.9 pts to UKMO at 89.7 pts and GFS at 88.3 pts. Then at 8 Days ECM has the leading spot from GFS with 70.7 pts to 65.5 pts. Finally at Day 10 ECM leads today at 54.4 pts to GFS's 53.1 pts.

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

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.png

MY THOUGHTS  The models have changed little over the last 24 hours and in general the main theme for the next few weeks is mirrored again this morning from yesterday. Taking it piece by piece we have a couple of rather cold days and some jolly cold nights to come with sharp frosts. Sunny spells through the day will make things feel OK away from the Northern facing coasts where a few wintry showers are likely. Complications begin on Friday when Low pressure slides South and develops swinging winds back into a cold SE, East then NE direction across the South of the UK making it feel very raw. Further North the weather looks like staying cold, fine and frosty. There is also of course the chance that some precipitation attached to the fronts from this Low will edge up into the South for a time with just a risk of a little rain, sleet or snow but this looks both marginal and limited in spread at best. Then as we look through next week the High pressure ridge to the North will move South cutting off the NE feed and returning windier westerly winds to the North. these subsequently spread to all areas next week as pressure falls from the North with the weather deteriorating for all with wind and rain followed by cold NW winds and wintry showers to end next week. As we look to the far end of the forecast period by far the most likely options shown within the clusters and ensembles today maintains a rather cold theme with NW winds across the UK and no doubt some rain or wintry showers to be had for many.           

Next Update Wednesday February 24th 2016 from 09:00

[mushymanrob]

this to my eyes spells a raw, bitter, overcast, day with and precip being confined to the southwest. unlikely to be snow away from higher ground - dartmoor maybe?

 

[I remember Atlantic 252]

Just now, mushymanrob said:

this to my eyes spells a raw, bitter, overcast, day with and precip being confined to the southwest. unlikely to be snow away from higher ground - dartmoor maybe?

 

Same as Valentines day just gone then, but yes cannot see any snow on there, could be a wet day for my location as showers move in off north sea

[mushymanrob]

1 minute ago, I remember Atlantic 252 said:

Same as Valentines day just gone then, but yes cannot see any snow on there, could be a wet day for my location as showers move in off north sea

im not expecting any showers, maybe a bit of light drizzle, but its cloudy as that upper occlusion straggling us would suggest.

[I remember Atlantic 252]

yes, but FI chart occlusion may disappear, I'm expecting showers off north sea, think the nasty easterly will happen

[Paul_1978]

On the face of it this looks like another "blink and you'll miss it" affair. All over by Monday/Tuesday next week .

[frosty ground]

7 minutes ago, Paul_1978 said:

On the face of it this looks like another "blink and you'll miss it" affair. All over by Monday/Tuesday next week .

Blink for a week and you will miss a run of below average temperatures and some sunny & clear weather.

Best not blink!

[MP-R]

5 minutes ago, frosty ground said:

Blink for a week and you will miss a run of below average temperatures and some sunny & clear weather.

Best not blink!

and your username sums up quite nicely the extent of cold over most of the UK for this week.

[Bristawl Si]

9 minutes ago, frosty ground said:

Blink for a week and you will miss a run of below average temperatures and some sunny & clear weather.

Best not blink!

It's end of Feb. Average temps here (imby) 8/9c. Below average = 5/6c. Cold? Yes. Overly cold? No. Deep freeze? Nope, except early hours of morning...maybe.

[Paul_1978]

10 minutes ago, frosty ground said:

Blink for a week and you will miss a run of below average temperatures and some sunny & clear weather.

Best not blink!

Fair point mate! I just wanted some snow….. and to be fair we are into a run of NWlys after a brief warm up around Tuesday next week (as it stands - a week is a long time in weather :-) )

[frosty ground]

5 minutes ago, Bristle boy said:

It's end of Feb. Average temps here (imby) 8/9c. Below average = 5/6c. Cold? Yes. Overly cold? No. Deep freeze? Nope, except early hours of morning...maybe.

Not sure what you added to my original post, i can see you made some statements and answered them but I fail to see what that has to do with my post.

[Banbury]

9 minutes ago, Paul_1978 said:

On the face of it this looks like another "blink and you'll miss it" affair. All over by Monday/Tuesday next week .

What and then open your eyes and you are back cold again, not that the cold ever cleared off

[Hull snow]

So are the charts still looking cold with the chance of snow ?

[cheshire snow]

1 hour ago, Paul_1978 said:

On the face of it this looks like another "blink and you'll miss it" affair. All over by Monday/Tuesday next week .

"In your own words"for newbies on here charts and explanation

 Please.

 Thanks

 C.S

[snowflakey]

850 temps look a little inconclusive for London, with a slight warming trend, but with a large amount of scatter after a couple of days.

[Summer Sun]

10 minutes ago, Hull snow said:

So are the charts still looking cold with the chance of snow ?

Some snow showers are possible especially on exposed coasts (but nothing widespread or significant this week)

Where we have sunshine and shelter from the wind / breeze it really isn't all that cold by day but nights will be cold and frosty

Edited February 23, 2016 by Summer Sun

[Northern Sky]

5 minutes ago, Hull snow said:

So are the charts still looking cold with the chance of snow ?

It looks chilly with a small chance of a few wintry showers, though of course that could change one way or the other. The low moving down the country which has been modeled around the 2nd/3rd of March may offer some possibilities, however it's miles out and the reality is NW'ly's usually lose their potency as they move towards actually happening. In short, and especially given your location, you might have to keep waiting.

[Paul_1978]

27 minutes ago, cheshire snow said:

"In your own words"for newbies on here charts and explanation

 Please.

 Thanks

 C.S

Yes fair point, I hold my hands up I was hasty with my post. Can't say fairer than that 

[Paul_1978]

45 minutes ago, Banbury said:

What and then open your eyes and you are back cold again, not that the cold ever cleared off

Yes fair point, as I've just replied, I hold my hands up for being too hasty .

[bobbydog]

paul was referring to snow not cold. (i thought it was reasonably obvious) i dont think anyone is disputing it will be cold. as it stands (for now) not much will be falling from the sky for most of us.