Model output discussion - 20th Feb onwards

[Weather-history]

3 minutes ago, northwestsnow said:

UKMO looks very interesting this morning 

http://www.wetterzentrale.de/pics/Rukm961.html

http://www.wetterzentrale.de/pics/Rukm1201.html

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

It looks to me the models have moved towards that low pressure having more influence on the 0z runs.

[Lukesluckybunch]

2 minutes ago, Weather-history said:

It looks to me the models have moved towards that low pressure having more influence on the 0z runs.

So is this still good for cold and snow?

[northwestsnow]

3 minutes ago, Weather-history said:

It looks to me the models have moved towards that low pressure having more influence on the 0z runs.

UKMO 144 looks convective to me - cant see the 850's etc but looks good

[bluearmy]

Euro trough are not usually modelled very well - certainly at the outset.  I would give it a few more runs before taking too much from where we may be by next Sunday. 

Could be under a ridge or a screamimg nor'easter.  

[MR EXTREMES]

well the ecm has backed away from the robust heights into atlantic and southern Greenland which was always going to be a risk although the vortex has taken a beating and has most likely contributed to the incoming cold its still able to dictate the patterns of weather around the northern hemisphere.

but the indications from this mornings runs is gfs is cold right though till the end ukmo looks pretty good with snowfall possible at some point but hard to pin down where it goes beyond t144.

and the ecm is cold but removes the cold quickly compared to lastnight although I feel its nowhere near certain and would advise caution of charts beyond t144 id be more inclined to suggest that cold spell is most certainly going to happen beyond fi I suspect that everything is flattened but with more chances of wintry weather into march.

its good to see the cold bottled up to the nw ne and north anything from them directions would be good chances of wintry weather.

any other direction easterly I don't think would be a use to us coldies as the coldest air more to the directions I stated.

[chris55]

ECM 00z just highlights how small disturbances could well bring ppn into the colder air. 

At t96 to t120 the small low edges into western parts.

 

[MR EXTREMES]

but the later runs on the ecm suggest relaxation of the cold but look at the deep purples heading west and sw if this goes any further west south west we could well be seeing something colder once again all in all good runs by the models although ecm last night was better in the short medium term.

but none of the runs are dreadful certainly possibility of wintry showers at least in the n ne and down the eastern side of the uk.

if we can get the purples pulling closer to the uk then a much more wintry set up could be possible.

I think this is close to being the best wintry spell in a few years

[MR EXTREMES]

17 minutes ago, bluearmy said:

Euro trough are not usually modelled very well - certainly at the outset.  I would give it a few more runs before taking too much from where we may be by next Sunday. 

Could be under a ridge or a screamimg nor'easter.  

I punt for a screamer and north east streamers.

but agree more runs certainly needed also get the cold in first.

very dramatic stuff from the models over the last week or so id never thought we would see charts like this two weeks ago

[karlos1983]

48 minutes ago, Lukesluckybunch said:

So is this still good for cold and snow?

Luke, I'm beginning to fear for your sanity or your computer If this predicted cold spell goes the way pear mate. 

[Paul_1978]

1 hour ago, northwestsnow said:

UKMO looks very interesting this morning 

http://www.wetterzentrale.de/pics/Rukm961.html

http://www.wetterzentrale.de/pics/Rukm1201.html

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

Why's that? Some reasoning would be good for newbies. 

[karlos1983]

Looking at the GEFS purbs, not a single 1 of the 20 show anything remotely mild at 144 and almost all of them have the trough to our south or close to the uk dragging on and easterly/ north easterly.  

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=144&code=1&mode=0&carte=1 

[JJS487]

52 minutes ago, Paul_1978 said:

Why's that? Some reasoning would be good for newbies. 

Correct me if i'm wrong (it's only my first post) but those models show an even further weakening jet stream that progresses with winds moving from a NW direction to a more Northerly direction. Such enables the continual feeding of cold air from north to south across the UK. Combine this with the moving low pressure system that sits just south of the UK on Sunday may allow for precipitation to be brought in off the Atlantic which once combining with cold air situated across the UK may possibly fall as snow? 

 

Hope I haven't made a fool out of myself on my first post there...

 

[Purga]

Pretty solid GEFS signal for a cold 7-10 days but little precipitation however apart from the next couple of days.

Still hope for some surprises i.e. convective showers if a strong ENE wind develops as indicated on the models.

[Severe Siberian icy blast]

5 minutes ago, JJS487 said:

Correct me if i'm wrong (it's only my first post) but those models show an even further weakening jet stream that progresses with winds moving from a NW direction to a more Northerly direction. Such enables the continual feeding of cold air from north to south across the UK. Combine this with the moving low pressure system that sits just south of the UK on Sunday may allow for precipitation to be brought in off the Atlantic which once combining with cold air situated across the UK may possibly fall as snow? 

 

Hope I haven't made a fool out of myself on my first post there...

 

Hi jjs487  yes this week we have northwesterly feed for the first half of the week and like you said fronts moving in toward the weekend , it's unclear as to how much of the U.K. If any they affect but as these sink southwards it looks very likely we will have some sort of easterly developing across much of England , not convinced we will see any ppn from the fronts approaching from the west but it will be nice to see some frontal snow for once . And maybe some wintry showers from the east through the weekend , but the uppers aren't that cold this week , but stil cold enough for snow I should think particualarly at night ,  I think we need those deeper uppers over Asia to move westwards to stand a proper chance of having deeper cold , which could happen if the -AO signature moves the cold west sufficiently to get involved in the flow coming down the western side of the high pressure toward the uk but it's a long way off yet .

a great first post from you and I'm sure your use to the rollercoaster you get to ride for free when you join here ! Enjoy the Pepsi max mate it's one hell of drop when we'r sat at the top and quite unexpected at times !!

[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 MONDAY FEB 22ND 2016

THE CURRENT GENERAL SITUATION   A weak cold front is moving very slowly South across Southern Britain with colder air following on behind from the NW to lie across all of the British Isles by tomorrow.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK is falling across the South to lie between 1500ft-3500ft across all of the UK by the end of tomorrow with this level anticipated to be maintained for the majority of this week Wintry showers will pepper Northern and Eastern hills and coasts at times.

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 shown to trough strongly to lie well to the South of the UK by the end of the coming week in association with Low pressure there. Later in the period there is some suggestion of the flow migrating back North towards the UK but in an undulating form.

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

GFS OPERATIONAL The GFS Operational Run today shows a couple of week with rather cold weather as the pattern of synoptics change to that we have seen of late. Low pressure develops to the South of the UK next weekend following a benign and quiet spell of weather this week with light winds through the run up to that with a few wintry showers and frosty nights. Then some rain, sleet or snow could affect the South for a time in a week with a very raw ENE wind. Then as we move further out the weather reverts to more changeable conditions again in mostly NW winds with rain and strong winds at times with conditions largely staying rather cold for much of the time allowing some snowfall on hills of the North.

GFS CONTROL RUN The Control Run today follows a similar route to the Operational with a slow return of Atlantic West or NW winds in Week 2 with rain at times following a week to 10 days of rather cold weather especially in the South where some rain, sleet or snow could occur a week from now in a cold and raw ENE wind for a time early next week.

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 suggest NW winds the most likely position we find ourselves in two weeks time. There are varying degrees of whether such a flow is cyclonic or anticyclonic based dependent on how close depressions to the NE are or how close the High pressure to the SW lies in relation to the UK in what appears likely to be rather cold conditions overall.

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 Low pressure slowly sinking South across the UK later this week and ending up to the South of the UK next weekend. In the interim period a lot of quiet and benign rather cold conditions seem likely with frost at night before some rain or perhaps sleet moves in from the West towards the weekend leading to a cold and windy weekend especially in the South with rain, sleet and hill snow a risk here while the North could stay cold and frosty.

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

THE FAX CHARTS The Fax Charts today shows quiet conditions through the working week with no more than occasional wintry showers in a slack North or NW flow this week and these mostly focused towards Northern and Eastern coasts. Fronts are shown to be approaching the West of the UK by the weekend as Low pressure develops and slips South to the West of the UK come Saturday.

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

GEM GEM today shows a lot of cold and eventually windy weather as Low pressure migrates to the South of the UK late this week and more especially next weekend and in the South where a strong and very raw East to NE wind develops for a time with some rain or snow in places. The NE flow is then cut off briefly as a ridge pushes up from the SW with frosts developing for many before further cold and unsettled weather is shown to move down from the NW again next week.

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

NAVGEM NAVGEM looks broadly similar in theme to the rest with the Low pressure areas slipping South of the UK by next weekend before filling up as a ridge develops from the SW across the UK by the start of next week cutting off the flow and introducing cold and frosty weather replacing the cold and raw conditions across the South next weekend. 

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

ECM ECM this morning follows the theme of the rest too with a spell of cold weather lasting for much of the period. Through this week a cold Northerly is the main ingredient and although the wind will be quite light some wintry showers will pepper the coasts at times and rain will threaten the South at first and again through next weekend as a raw NE flow develops in the South for a time perhaps with a little hill snow in places. This is then displaced next week as somewhat less cold WNW winds develop for a time with rain and strong winds gradually pushing SE across the UK with cold air threatening again towards the end of the period towards the second weekend behind the Low pressure bringing the milder conditions.

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

ECM 10 DAY MEAN The 10 day mean chart today strongly supports the NW flow hinted at by other output too for the start of Spring with the likelihood of chilly NW winds bringing rather cold weather to many areas to start March with rain at times falling as snow at times on higher ground as the pattern of High pressure well to the SW and Low pressure over and to the NE of Britain establishes.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The theme is 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.

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 92.0 pts to UKMO at 90.0 pts and GFS at 88.3 pts. Then at 8 Days ECM has the leading spot from GFS with 71.8 pts to 65.9 pts. Finally at Day 10 GFS leads today at 54.6 pts to ECM's 54.3 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  Some good consolidation between the models this morning on the process of how colder air than of late establishes across the UK this week and then looks set to remain in one shape or form for some time. We currently have a weak cold front straddling the South of the UK which is set to clear tomorrow and set up a spell of slack and cold Northerly winds with some wintry showers near Northern and Eastern coasts and hills and more importantly give rise to some sharp night frosts under clear skies. Then towards the weekend pressure will of fallen somewhat across the UK and with troughs trying to edge in from the West some cloud, rain and hill snow could affect the West and SW for a while towards the weekend. As the parent depression bringing this weather develops further and lies to the South of the UK a spell of raw and cold ENE winds in the South will develop and there could be a little rain or snow in extreme Southern counties for a time. Then next week shows a strong build of pressure ridging up from the SW and though cold with frosts at night it will feel less so as the winds will of died. Looking further ahead still the models are pretty much in agreement that further rather cold and unsettled weather will move down over the UK wth rain and snow at times in winds settling strong NW'ly. This theme has strong support from both the GFS Cluster data and the ECM 10 day Mean Chart this morning which means it has a good chance of verifying and falls in line with the Met Office predictions of late too. So there we have it a couple of weeks of cold weather to come, something that I have all too rarely said this Winter. However, for those seeking snowfall things look less exciting and while there are some chances of this over the period and not just in the North widespread snow events look unlikely with the hills of the North as usual the most likely locations to see this late in the period as the NW'ly flow strengthens then. Frosts look much more common with someone somewhere having frosts most nights through the period. So for now at least Spring weather looks on hold which in itself is a turnaround on recent weather patterns and things may not feel too bad as the days are now lengthening by 2mins/day night and morning at this time of the year.           

Next Update Tuesday February 23rd 2016 from 09:00

[mushymanrob]

11 hours ago, Man With Beard said:

However - one for you MushyManRob - gettting closer to the Greenland High on the latest NOAA 8 to 14 dayer - and even an Omega block looks possible now. 

 

the chart shows a weak greenland high (compared to the strong azores high) but the flow between them is still westerly and pretty steady. and ridging between the two highs will be transitory. these charts do not support a strong northern block imho, but troughing to our south which does support an easterly / northeasterly / northerly surface flow.

a north easterly of course doesnt mean sunshine and snow showers, it could well bring a stratus-fest, especially for eastern areas - but at least itll be dry.

i dont see anything more then a 'normal' cold spell for the time of year. these synoptics would be much more potent a month ago but daylength and sun strength is rising now and it doesnt look to me like a repeat of 2013 - currently at least.

[fergieweather]

Only points of emphasis I'd add to Gibby's summary are re Fri-Sat:

- sufficient signal still within EC-EPS and MOGREPS to maintain a risk of more developmental outcome with gales/severe gales into SW/S, with attendant risk of heavy rain and lower risk significant snow

- mismatches this morning between WV imagery and model expectations in critical source area for evolution later this week illustrates the low confidence message re how things will unfold: treat deterministic fields by Fri with a due level of doubt. May remain unresolved until short lead time.

Edited February 22, 2016 by fergieweather

[fergieweather]

5 minutes ago, mushymanrob said:

i dont see anything more then a 'normal' cold spell for the time of year. these synoptics would be much more potent a month ago but daylength and sun strength is rising now and it doesnt look to me like a repeat of 2013 - currently at least.

Correct: it's expected to be a cold phase not at all unusual for this time of year and nothing like 2013. No talk of severe cold. It'll *seem* more pronounced because of milder winter backdrop, plus longevity (circa 2 weeks; longevity signal then turns v mixed/less bullish, but possible colder/blocked periods at times further into March). 

[karlos1983]

8 minutes ago, fergieweather said:

Correct: it's expected to be a cold phase not at all unusual for this time of year and nothing like 2013. No talk of severe cold. It'll *seem* more pronounced because of milder winter backdrop, plus longevity (circa 2 weeks; longevity signal then turns v mixed/less bullish, but possible colder/blocked periods at times further into March). 

So snow chances look limited then if it's just a cold phase not unusual for this time of year....?

Edited February 22, 2016 by karlos1983

[winterof79]

8 minutes ago, karlos1983 said:

So snow chances look limited then if it's just a cold phase not unusual for this time of year....?

The thing is though,it hasn't been normal fayre for a long time.I would call it as being well below what we've become accustomed to.If we had regular 850s of -8 then I could accept the above comments.

[Snowynorth]

Just a typical cold spell, nothing unseasonal and nothing noteworthy.

Generally dry throughout the week, pleasant winter sun during the day with harsh frosts overnight. 

Very little in the way of precipitation and for areas where precipitation is greatest (that area of low pressure) it will be of rain. 

Then when the low pulls away and draws in a more easterly flow Europe isn't cold enough so what you'll see is wintry showers a majority of which will be of rain within 30-40 miles of coastal areas in the north, east and south-east.

Europe needs to cool down a lot for anything noteworthy later in the week which I suspect it won't.

 

 

Edited February 22, 2016 by Snowynorth

[karlos1983]

8 minutes ago, winterof79 said:

The thing is though,it hasn't been normal fayre for a long time.I would call it as being well below what we've become accustomed to.If we had regular 850s of -8 then I could accept the above comments.

 

The only reason I'm asking, is because I'm wondering if the Met have different progged 850's than we are seeing, because surely, -8 T850's are not usual affair for the uk coming into March, and that in my book if ppn is present would be snow for many?

[bobbydog]

21 hours ago, fergieweather said:

Temperatures are about to start a decline to below average and expectations are for quite a few weeks of that situation remaining, with cold/bocked weather dominating. It could last well into March. Longer range products have only just started reacting to the MJO phase 7 (which tends to have instantaneous response in outcome here) due to lag. Now we can see the direction becoming clearer in GloSea5 and EC Monthly, we await the operational model centres to catch-up. Storm track is expected to become ever more southerly in next 1-3 weeks, with inherent prospect of these passing to S-E of UK and resultant risk of wintry hazards. It's total chalk and cheese change versus winter so far and evidence is now compelling for most protracted period of below-normal temperatures seen for some time. It matches exactly the UKMO Seasonal Team assessment for this winter, but only now is the model evidence becoming well aligned. 

Ian. your post from yesterday came across to many as good confidence of a protracted period of "below normal" temps for "quite a few weeks". (some people would read that as 'into the freezer for months...')  obviously this is not your personal forecast- its what the longer range models are (were?) showing.

you dont seem so confident today. are the LR models backing away from an extended cold(er) period?

Edited February 22, 2016 by bobbydog

[Lukesluckybunch]

Wow the 06z is look fantastic!

[fergieweather]

28 minutes ago, karlos1983 said:

So snow chances look limited then if it's just a cold phase not unusual for this time of year....?

As usual at this time of year, expect any (less significant falls of) snow by day to either struggle to settle and/or melt at low levels under any insolation. Settling will generally occur readily only at the WBFL elevation or above, but of course still remain a more widespread hazard at night.