Model output discussion - 20th Feb onwards

[Summer Sun]

After a wobble last night ECM is back on track bringing in some significantly milder air later next week and into the following week

With the days getting longer and the sun getting stronger we could be seeing temps reaching the high teens in the south should we see some sunshine

[knocker]

1 hour ago, Banbury said:

Again after mid month we see another change to cooler weather

 

Quite correct

Sidney's nephew is already smelling the coffee

Edited March 5, 2016 by knocker

[Frosty.]

Really stunning Ecm 12z from the end of next week onwards which is almost a carbon copy of the superb week 2 from the Gfs 6z op run. I hope this gains momentum and we see high pressure taking centre stage for a change! This run eventually shows very warm weather for so early in the season and following the winter that never was, I hope early spring brings increasingly warm and settled weather during the mid march period.

[I remember Atlantic 252]

great charts Frosty, hope mushymanrob a few posts above is wrong

[Frosty.]

1 minute ago, I remember Atlantic 252 said:

great charts Frosty, hope mushymanrob a few posts above is wrong

Yes they are great charts, hope they verify!

[chris55]

Seeing as my house currently does not have a roof on it lol!!! this chart is just lovely.

(by the way I am not currently living in it hahahah)

 

Edited March 5, 2016 by chris55

[phil nw.]

4 minutes ago, chris55 said:

Seeing as my house currently does not have a roof on it lol!!! this chart is just lovely.

(by the way I am not currently living in it hahahah)

 

You may need some temporary covering on it around Tues/Weds Chris as we see the Atlantic  fronts moving across.

however it does herald the change to much better conditions by the end of the week already discussed as that Azores high ridges this way.

[chris55]

13 minutes ago, phil nw. said:

You may need some temporary covering on it around Tues/Weds Chris as we see the Atlantic  fronts moving across.

however it does herald the change to much better conditions by the end of the week already discussed as that Azores high ridges this way.

Thanks phill. We have been open to the elements for a while now and only lost a few days to the weather which isn't to bad! Though the settled and warm ECM Op is certainly inviting

Note my temporary roof over the kitchen lol!

(totally off topic I know)

[fergieweather]

Unanimous 12z EC cluster support for the settled anticyclonic story 13-15 March inclusive...at least. There's two clusters thereafter to end of run (20th), the largest of which continues the settled theme beyond 15th until it relents later (below). Interestingly and perhaps instructively, the increasingly cyclonic look evident by 20th on EC12z cluster 1 now tallies with longer range suites, which also go that direction w/c 21st (d15). Thereafter lies the conundrum: whether the UK sees a more blocked pattern eventually set-up that could go 50-50 (either blocked as an anticyclonic regime here, or as a cyclonic one). Whilst the long range products do agree on GPH falling after d15, as noted on Thurs the latest EC Monthly offers no useful signal thereafter re temperatures etc, with GloSea5 adding little additional steer. However, GloSea5 strat diagnostics do continue to show some degree of downward propagation of post-SSW easterlies late March-early April and as the UKMO note, should those reach the lower troposphere (and that's not *yet* a given), then the risk of more meandering jet and blocking/colder than average weather would increase into the turn of month. At present, the outcome later this month is too tricky to call, but at least the likelihood of a pleasant spell into mid-month continues to find growing support.

[mushymanrob]

1 hour ago, mushymanrob said:

i still think (unfortunately) the ecm and gfs current ops are too progressive with the eastward progress of the displaced azores ridge, (and consequently the warmest of the weather) as the noaa 500 mb charts currently suggest the displaced azores ridge is centered to the west of south. 

 

1 hour ago, I remember Atlantic 252 said:

great charts Frosty, hope mushymanrob a few posts above is wrong

i hope so too ira252 !!! but i cannot reasonably pick which noaa charts to believe and which to ignore. i either trust them no matter what they say, or i drop them altogether.

sorry, but todays noaa 500 mb charts still keep the displaced azores ridge just to our west and the mean upper flow across the uk still north of west. i hope they change, i hope this is one occasion when the ops 'beat' the anoms. but they have been proven to be on the ball far far more often then the ops.

so as things stand, the best of the op runs warmth is unlikely to verify imho, not that itll be too bad though but not quite as amplified (warmth). ?

[Singularity]

Just time for a quick post from me this evening;

For a split vortex event, the negative AO trend should initiate within a few days, and peak some 3-4 weeks later in time. So the Met Office thinking seems to be in the right ballpark although at the long-end of the spectrum.

I actually had a bit of a revelation just now but it was to do with the MJO instead; although a phase 8 MJO composite for March looks like this:

 - there is actually a tendency for a mid-latitude block in the vicinity of the UK to develop by mid-month, after which it makes a departure by the final week. It's the reason why the whole-month anomalies aren't very strong; the phase of troughs into Europe and ridges into the high Arctic (the recent/current pattern) is a little longer-lived but the mid-month changes certainly leave their mark. 

So... the slower decline of the MJO in phase 8 may well be serving to boost the theme of a UK high for mid-month. This being different to what would happen if the MJO stormed on into phase 1 (not currently the form horse).

Then it comes down to how soon the negative AO trend produces an environment suitable for the UK high to move to the high latitudes. It does unfortunately seem almost inevitable for the second half of March.

[knocker]

As already stated looking good for some settled and warmer weather starting towards the end of next week. The anomalies all agree with the trough mid Atlantic and the HP very adjacent to the UK with the upper flow in the westerly quadrant. It does depend to a certain extent on the exact orientation of the surface HP but there is some wiggle room it looks okay for a few days.

Moving forward it's not quite so clear cut. NOAA does build weak heights towards the Pole but still maintains a westerly flow so no major problem. The EPS 10-15 is actually very similar although perhaps orientated more towards Greenland. This is actually a bit deceptive as it's a five day average and if you look at individual days towards the end of the run the HP retrogresses and with the trough to east edging west as well the upper flow veers to N of W bringing the temps down to average and again some periods of unsettled weather. I think this is still a work in progress.

[Man With Beard]

4 hours ago, Banbury said:

Again after mid month we see another change to cooler weather

A short period of HP for the UK giving milder conditiond before a change to cooler /colder weather as we head towards Easter, falling Snow cannot be ruled out

 

I think you're absolutely right to keep posting these ensemble charts as I think they make a point. Pressure is going to rise towards the UK next weekend - but will it rise through us? Cold is finally boarding the Siberian express to Europe - but how deep? The warm weather will surely come now, but it's going to be fascinating to see what it leads to after. A full blown Siberian blast is not completely dead in the water.

[TomDav]

Scandinavian trough at the end of the GFS 18z. Looks like the beginning of a colder, blocked pattern if it verifies

[Frosty.]

The Gfs 18z shows quite a change from next Friday with the Azores High building in and temperatures climbing into the mid teens celsius making it feel very pleasant in the strengthening March sunshine. High pressure becomes centred slap bang over the UK bringing a lovely spell of settled and pleasantly warm weather to the whole of the British isles with light winds and plenty of sunshine but with overnight mist and fog patches although that should burn off to give sunny afternoons / evenings..Fingers crossed it looks like a settled and warm spell is increasingly likely by next weekend and for much of the following week!

[Interitus]

1 hour ago, Frosty. said:

The Gfs 18z shows quite a change from next Friday with the Azores High building in and temperatures climbing into the mid teens celsius making it feel very pleasant in the strengthening March sunshine. High pressure becomes centred slap bang over the UK bringing a lovely spell of settled and pleasantly warm weather to the whole of the British isles with light winds and plenty of sunshine but with overnight mist and fog patches although that should burn off to give sunny afternoons / evenings..Fingers crossed it looks like a settled and warm spell is increasingly likely by next weekend and for much of the following week!

Warm moist air and SSTs at their lowest means cloud will be an issue for many initially.

[skifreak]

For the NW Highlands there is a 10ºc difference in 850hpa temperatures at noon on Thursday on the 00z GFS compared to the 12z on Saturday, instead of blizzards and significant snowfall on the hills the freezing level would be well above the tops with heavy driving rain at all levels. Such a turn around in 12 hours suggests it's far from certain what is going to happen, blizzards followed by the high moving swiftly far enough North to give dry calm conditions over Highland Scotland is probably too much to ask for! lol! 

An observation regards model performance at short range from Lake Tahoe, CA. Yesterday evening PST,  the Met Office App was saying Saturday would have a few patchy light showers during most of daylight hours, with only a small chance of precipitation most of the morning after overnight rain cleared. The Weather Channel which I assume is using the GFS, had 100% risk of heavy rain all day for South Lake Tahoe. I was more than sceptical about the Met Office data, but the Met Office App was on the money, rain cleared quickly to give bright and sunny spells mid-morning, few patchy drizzly showers in the afternoon - GFS was way out at this location! 

Edited March 6, 2016 by skifreak

[Frosty.]

6 hours ago, Interitus said:

Warm moist air and SSTs at their lowest means cloud will be an issue for many initially.

 My bad, sorry I left that minor detail out of my earlier post but I was describing the increasingly warm and Anticyclonic outlook on the 18z!

[knocker]

A quick overview from the woodshed of both the GFS and ecm. After quite a cold start and then a very wet and windy Tues/Wednesday HP then dominates proceedings with temps rising to a little above average.

Still looking at retrogressing of the HP late in the period instigating a more zonal flow and thus becoming more unsettled with temps nearer the average. As previously stated a watching brief required here.

Edited March 6, 2016 by knocker

[I remember Atlantic 252]

12 hours ago, mushymanrob said:

i still think (unfortunately) the ecm and gfs current ops are too progressive with the eastward progress of the displaced azores ridge, (and consequently the warmest of the weather) as the noaa 500 mb charts currently suggest the displaced azores ridge is centered to the west of south. 

blast! will be miserable here

[Frosty.]

We are on track for a significant change to settled conditions as the Azores high builds in from next Friday with temperatures into the mid teens celsius and the jetstream forced further north, we get some of the warmest weather since. Err.. December

The Gfs 00z shows a spell of very pleasant conditions but as the high drifts north by north west, cooler air further east is drawn across the UK later next week but this isn't resolved yet, the anticyclone could become centred further east thus extending the fine and warmer spell...anyway, it will make a very pleasant change from Atlantic lows battering the uk as they generally have during the winter that never was!!

[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 SUNDAY MAR 6TH 2016

THE CURRENT GENERAL SITUATION A chilly North or NW flow will continue across the UK for the next day or two with a disturbance running South close to Western Britain late today and for a time tonight.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will remain around about the 2000ft mark for much of the weekend but maybe a little higher than this across the far SW for a time late today and tonight. Snowfall amounts will be small or negligible for most through this weekend with any snow light and fleeting over higher ground exposed to the Northwest, North and NE.

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

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

MODELS-2 WEEK HEADLINE  Rather cold and breezy at first with rain or showers at times with snow on hills. Gradually becoming more settled and less cold then with bright days but cool possibly frosty nights.

THE GFS JET STREAM FORECAST  The Jet Stream has a few more days of blowing South across or just West of the UK. By midweek the flow buckles NE and breaks off from the Southern element with the main arm then tracking NE well to the North of the UK becoming fragmented and variable in position and weaker in strength through Week 2 as High pressure lies close to the UK blocking any direct West to East passage.

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

GFS OPERATIONAL The GFS Operational Run's theme today is for the current cold Northerly flow to give way to a cold and very unsettled day Tuesday as Low pressure spins SE down across the UK with strong winds, heavy rain and hill snow possible for a time. Then the middle of the week sees milder and cloudy conditions with further rain at times before High pressure builds up from the South across all areas settling the weather down to fine and sunny weather but with some night frosts. Temperatures by day look quite respectable before a return to unsettled and changeable weather is featured to return towards the end of the period, moving in from the West and NW.

GFS CONTROL RUN The theme of the Control Run shows a similar evolution with High pressure taking control of the weather centreing close to the UK in the second week. Any Spring warmth may be more tempered by different positioning of the High more to the North and NE on this run with the possibility of chilly conditions returning from the East especially later with a cold ESE wind picking up across England and Wales.

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 show a bias towards High pressure probably most likely to lie close to SW Britain with it's influence stretching across much of the UK. Some members but a much less significant amount project the possibility of a cold Northerly with High pressure out to the NW but this is only shown by a 10% cluster. 

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 a chilly wet period towards Tuesday and Wednesday as Low pressure moves SE across or just to the East of the UK with some hill snow still likely. Then a change to milder and lighter Westerly winds with some rain chiefly in the North sets up by next weekend with High pressure increasingly influential just to or over the South by the end of it's 6 day period.

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

THE FAX CHARTS The Fax Charts show a very slow change to the pattern across the UK in the next 5 days. In the process will be several days of troughs straddling the UK from the NW then west with rain at times for all and cold enough for some snow at times on the hills up to midweek before the milder air off from off the Atlantic wins out later this week.

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

GEM GEM this morning maintains the theme shown by GFS today in changing the orientation of movement of Low pressure systems away from the SE direction they have taken of late to a more easterly direction much further North of the UK. This has the effect of cutting off the cold NW or North feed and replacing it with milder Atlantic Westerlies. Pressure is then shown to build from the South by next weekend with a sustained spell of dry early Spring weather with sunshine by day but with an increasing likelihood of the return of chillier air and frosts at night as the High responsible migrates out to the NE of the UK later.

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

NAVGEM NAVGEM too shows milder conditions take hold after a chilly and wet period towards midweek. High pressure then builds NE across Southern Britain gradually extending to many areas by next weekend. With a source of winds by then from the SW temperatures should recover to average or perhaps a little above by day although patchy night frosts may still be possible.

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

ECM ECM today follows the theme too with High pressure steadily building North across the UK by next weekend following the messy transitions from the current rather cold pattern with rain and patchy hill snow between now and more especially midweek. As High pressure builds a spell of Westerly winds and rain at times affects the North before all areas settle into dry and fine almost Springlike conditions with light winds. There is still plenty of scope for night frosts to occur and later in the run as the High drifts further North it maybe that temperatures by day fall back somewhat too as uppers cool a little and an Easterly feed to the wind might develop. 

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

ECM 10 DAY MEAN(12z) The new 240hr mean Chart seems late on release this morning but the main theme of the last night's chart seems unlikely to be changed much this morning given the Operational's message which has High pressure ridged strongly across the UK with a fine and benign weather pattern expected across the UK in 10 days with average temperatures at least for most parts.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The trend is well set for the weather to become fine, settled and less cold from the middle of the week with solid cross model support for High pressure to build across the UK.

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 97.6 pts to UKMO's 96.9 pts while GFS lags behind at 96.1 pts. At 5 days ECM leads with 90.7 pts to UKMO at 88.2 pts and GFS at 85.9 pts. Then at 8 Days ECM has the leading spot from GFS with 64.9 pts to 60.5 pts. Finally at Day 10 GFS has the lead from ECM with a score of 48.2 pts to 46.8 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  There is considerable cross model support for a change of weather type as we move through this week with Wednesday or Thursday looking the likely day of transition. What we have now is the same rather cold and unstable NW airflow down across the UK with various disturbances threatening the UK with rain and hill snow at times. However by midweek a shift of the South flowing Jet stream to a less strong West to East flow North of the UK looks probable allowing rising pressure from the South to gradually extend it's influence at first to the South by the weekend and later to all areas with the possibility of a strong High cell sitting directly over the UK in a week or so. It would be too easy to say this will mean wall to wall sunshine and high Spring temperatures but we have to remember it is only March and cloud amounts could scupper this element of proceedings but nonetheless there looks like being a period of sustained dry conditions with light winds. Clear skies at night could allow for some night frosts but daytime levels look like being average at worst as hinted at before dependent on cloud amounts. Then as we look further out into the second week signs that the High might want to regress towards the NE North or NW are all shown by some output so the general feeling is that while staying dry temperatures could fall back somewhat as winds settle from an easterly or NE quadrant. This is all a long way off but it is nice to see sound cross model support for a period of High pressure to allow the extra hours of daylight and lower humidity values expected to dry up the ground in preparation for the Summer growing season.

Next Update Monday March 7th 2016 from 09:00 

[Summer Sun]

Anyone else having issues with the ECM ens? they appear to be stuck on yesterdays 12z

[Frosty.]

Fantastic Ecm 00z from next weekend onwards as the Azores high builds in, very spring like conditions develop with pleasantly warm sunny spells but still with chilly nights and a risk of mist / fog patches. It looks like a settled spell is set in stone now, duration not clear but something in the region of 3-5 days, perhaps 5-7!

[John Badrick]

5 minutes ago, Frosty. said:

Fantastic Ecm 00z from next weekend onwards as the Azores high builds in, very spring like conditions develop with pleasantly warm sunny spells but still with chilly nights and a risk of mist / fog patches. It looks like a settled spell is set in stone now, duration not clear but something in the region of 3-5 days, perhaps 5-7!

But this is for nearly a week away. No way set in stone this far out, just like the winter snow mania charts we were seeing get watered down, why would you expect charts that show mild conditions verify