Spring Model Discussion 18Z 9/3/13 onwards....

[Summer Sun]

Pleased to see ECM on now showing some milder hints this morning

Mid teens for the south even with the likely rain

Temps around the low double figures possibly for the south a bit lower the further north you go

[Frosty.]

I'm expecting some ebb and flow with the cold block initially strengthening to the north and east but then comes the atlantic attack which will make inroads but I still expect the cold block to win this particular battle, notice how the cold block on the gfs 00z is slowly watered down over time but since we are heading towards april, it's to be expected. I do think there will be a significant snow event somewhere in the uk later in the week and into next weekend, most likely to be further north and east.

[Weather-history]

It's not far off this set-up during the second half of March 2001

[UV-RAY]

Pleased to see ECM on now showing some milder hints this morning

Mid teens for the south even with the likely rain

Temps around the low double figures possibly for the south a bit lower the further north you go

So it's a choice between cold rain and warm rain then! For the next 7-10 days below average temps look likely for the bulk of the UK, thereafter returning to normal values for a time at least. Going off the CFS charts which have been pretty bang on the money over the last year, then any warm up looks like coming during the latter part of April into May.

[Supacell]

oh i agree that it is a classic model set up for frontal snow... but these breakdowns for me (ok nimby) are hit and miss, even in winter when ive hoped for snow (a long time ago, lol) its often been a disappointment although just to my north, the peak/pennines have had a pasting. plus the time of year, daylength, sun strength. in winter these synoptics would be very snowy, im just far from convinced that its a threat (to me).

and of course things can change either way, we are talking what might happen in 5+ days time in a very unstable atmosphere.

i think the only certainty for the next week is that it wont be warm! lol.

Coming from the Derby area I can concur with this post with hit and miss being a good description of breakdowns. In Belper it is a little more hit than miss, with slightly better altitude helping out. As I said in the regional thread, i remember plenty of times when there has been snow in March and April, and plenty of times when it has settled.... I do not remember any occasions though where snow has settled and stuck around IMBY. As soon as the sun gets out at this time of the year then the snow will melt.

Next week looks very cold and somewhere is likely to get a good accumulation of snow from being on the cold side of any frontal events. Even around this there could be some good blankets of snow during any heavier showers or where snow falls overnight (such as in parts of the southern Midlands last night) but again, as soon as the sun appears all that snow will melt very quickly.

It is a different story up in the Peak District though. I have spent a lot of time up there in recent years and have seen some very deep snow (March 2006 for example). Up here the rules regarding snow melt in March does not seem to apply. It confuses me why not as the sun is still just as strong as it is on lower levels.

Last year I was living up in the Yorkshire hills and we had a huge fall of snow on the morning of April 4th with gales and blizzards like i have never seen before. There was over a foot of snow and this stuck around for the next 2-3 days (albeit melting over this time).

Sorry for the long winded post but my point is, i think there will be snow this week and somewhere will get a dumping. But, away from the higher hills it will be a transient covering - how long depends on how long you are under the frontal snow for.

Edited March 17, 2013 by Supacell

[Harsh Climate]

It's not far off this set-up during the second half of March 2001

It's looking much better than that IMO, this could be one of the wintriest march for decades.

Edited March 17, 2013 by Harsh Climate

[Alex]

Chances seem higher to me this morning of the current heights to our northwest slipping southeastwards, taking residence over Scandinavia before it again slips into mainland Europe, this would slowly bring drier weather into the equation and would eventually bring some warmer uppers so fingers crossed for potentially a touch of spring over Easter?

MJO is progged to move into phase 1 which supports a trough to the west of us with heights to our east during late march/early april and a decreasing GLAMM index should help reduce the northern heights.

Despite my optimism, I think the ECM is a good example of a energetic change and although the heights slip away, they slip too far away and we are left with the trough not too far to our west.

Catch my weather views on my personal twitter: @alexbweather - add me!

[Frosty.]

It's looking much better than that IMO, this could be one of the wintriest march for decades.

Agreed, it's a poor comparison. We are on the cusp of another wintry week with all the winter hazards and the kitchen sink for good measure.

[Bradowl]

Just for Gavin I do hope and think it will turn warmer by May.

[Snowman.]

uhoh

[winterof79]

true, extremes do happen, but are highly unlikely as this winters ecm outputs have proven. ive never said they wont happen, but are unlikely...especially when the extreme is in fi.

erm... but you snow lovers are repeating the same thing over and over again... you cannot justifiably throw that at me without equaling that criticism at everyone.

appreciate the support guys

with respect.... thats foolish. whether the gfs is as accurate as the ecm or not is pretty meaningless as they are both very close. the gfs has out performed the ecm, look how many times this year the ecm has produced record cold predictions only to have them tempered and back in line with the more sober gfs's. but note, im not saying the gfs doesnt do that either, they are both guilty, they are both nearly as good as eachother.

....and this morning,the ecm lead big freeze is yet again downgraded to a few hours midweek, returning to what the models were showing prior.

all models agree that itll get gradually colder from today onwards bottoming out wednesday night with a sharp frost. cool, changable showery weather , some heavy, some wintriness, nice in any sun but sun will be at a premium.

the models start to diverge though as to the timing of the expected atlantic incursion thursday onwards. this mornings gfs 00z is possibly the most foreward suggesting a slow but steady progression thursady onwards. the ecm 00z suggests a messier affair with two attempts before the milder wins out. difficult to predict the outcome between attempts, the ecm also delays the timing and agrees with the ukmo fri-sat with a raw southeasterly before milder air 'wins out'. the ukmo doesnt go out far enough but it suggests a biting cold raw southeasterly .

snow chances are possibly greatest on wednesday, but location and altitude will impact on these chances, plus its not likely to settle, melting after the shower has passed.

frontal snow?.... i dont think so, the chances have been downgraded this morning. the progress of the milder air northeastward thursday onward is going to be a slow affair (on this mornings models), the fronts can be picked out where the isobars kink, ecm t144

http://www.wetterzen...n/fsecmeur.html

thats one chart but its not alone, you can see the uppers are milder ahead of the frontal precipitation zone. so IF (and i take heed of john holmes advice on guessing precipitation more then two days ahead) theres and snow, there wont be much before itll return to rain. of course altitude must be considered.

tbh this weeks expected weather isnt far off what id expect for early march, so not quite 'normal' for mid march, but not too far off, below average/cool.

the gfs in fi suggests a pressure rise, sunny days, frosty nights, until the high sinks allowing higher uppers around the top which would probably be cloud laden. but thats fi, fantasy island or forget it.

Looks cold from Tuesday - Sunday

http://www.meteociel...map=0&archive=0

And more than just showers

http://expert-images...031812_1706.gif

http://expert-images...031906_1706.gif

As for no fontal snow

http://www.meteociel...1-144.GIF?17-12

http://www.meteociel...0-144.GIF?17-12

http://modeles.meteo...gfs-0-144.png?6

http://modeles.meteo...gfs-2-144.png?6 You are quite possiby incorrect.

Edited March 17, 2013 by winterof79

[Snowman.]

Never mind it comes half way through April.

[bluearmy]

Gfs 06z low res fits in well with what i posted earlier re naefs fi.

[mushymanrob]

sorry guys, but this chart is not one for frontal snow! it demonstrates exactly why i doubted in my earlier post the we will get much if any at all. it clearly demonstrates milder air drawn up infront of the frontal zone, pushing the much needed 528dam away.

[cooling climate]

The bitterly cold pool that was once being shown over northeastern Europe

has now all but disappeared although it is still very cold mind.

For the midlands south the GFS is not as cold as the Euro models in the

semi reliable time frame but I would prefer to see what this afternoons

12z has to say rather than pass judgement on the 06z run.

As far as post t144 their is to much inter run varibility to make any

sense out of what lies ahead.

[mushymanrob]

Looks cold from Tuesday - Sunday

http://www.meteociel...map=0&archive=0

And more than just showers

http://expert-images...031812_1706.gif

http://expert-images...031906_1706.gif

As for no fontal snow

http://www.meteociel...1-144.GIF?17-12

http://www.meteociel...0-144.GIF?17-12

http://modeles.meteo...gfs-0-144.png?6

http://modeles.meteo...gfs-2-144.png?6 You are quite possiby incorrect.

didnt say 'no' frontal snow exactly, i said i dont think so, and that IF we get any it wont be much, altitude taken into consideration. the fax chart i just posted highlights my point.

of course i might be incorrect, the charts are going to modify, but hey..who hasnt been incorrect in their interpretation of the charts? look back through the model threads, im still waiting for the various dumpings that were promised!

Edited March 17, 2013 by mushymanrob

[bluearmy]

sorry guys, but this chart is not one for frontal snow! it demonstrates exactly why i doubted in my earlier post the we will get much if any at all. it clearly demonstrates milder air drawn up infront of the frontal zone, pushing the much needed 528dam away.

Rob, the flow ahead of the precip is off the continent. Dp's will be low as a result. that system is going to slide a lot of its energy se so no sign of the isobars going west of south for most of the uk. The 528 dam line is of no significance with a continental flow.

Lets hope this verifies so we can see the results. I cant recall when a day 5 fax last verified!!

[Weather-history]

Agreed, it's a poor comparison. We are on the cusp of another wintry week with all the winter hazards and the kitchen sink for good measure.

I think you mean poor in comparison, I don't think it's a poor comparison. The general synoptics are there and arguably the angle of approaches in March 2001 is better than what GFS 06z op run is showing. If the angle of frontal approach is like March 2001 and with that cold pool there it will be even snowier than March 2001 event.

Edited March 17, 2013 by Weather-history

[mushymanrob]

Rob, the flow ahead of the precip is off the continent. Dp's will be low as a result. that system is going to slide a lot of its energy se so no sign of the isobars going west of south for most of the uk. The 528 dam line is of no significance with a continental flow.

Lets hope this verifies so we can see the results. I cant recall when a day 5 fax last verified!!

not so sure mate, the chart prior suggests that the air is pushed off biscay into northern france before being drawn up ahead of the system.

[lorenzo]

Couple of teleconnection charts to summarise just how much of a negative plummet things have taken, you wait all winter for blocking to take hold and then...

Also from last nights GFS 12z run both TC's still looking at -1 into the start of April.

Pretty safe to say March is going to finish on the colder side of Spring conditions.

ECM uppers profile for mid week and a look at how GEM sees the snow playing out.

Finally an averaged mean from ECM that shows the mid-atlantic trough being the prominent feature in our location as the blocking wanes.

Whilst much of Winter has been a frustrating chase on the models, March has been a pleasing surprise watching things unfold with continued interest. In the next 24 hrs can the -10 uppers reach our shores spinning out of Scandi..

Edited March 17, 2013 by lorenzo

[Ian Brown]

sorry guys, but this chart is not one for frontal snow! it demonstrates exactly why i doubted in my earlier post the we will get much if any at all. it clearly demonstrates milder air drawn up infront of the frontal zone, pushing the much needed 528dam away.

Rob, the surface flow is from the continent, you always see the 528 dam shown to be ahead of the PPN in this situation, and typically snow can fall in such a situation with a dam level in the low 530s

[cooling climate]

It's looking much better than that IMO, this could be one of the wintriest march for decades.

The weather for the week video is somewhat misleading. As I remember on the

Tuesday 20th we here in Herts and southern England had maxima of 3c with heavy

snow expected during afternoon evening. The snow came but was sporodic in nature

and did not settle.

In Wales it was a different story altogether with the snow setting in during the

morning and afternoon with maxima of 0c and up to 6inches of snow.

Edited March 17, 2013 by cooling climate

[snowking]

Rob, the flow ahead of the precip is off the continent. Dp's will be low as a result. that system is going to slide a lot of its energy se so no sign of the isobars going west of south for most of the uk. The 528 dam line is of no significance with a continental flow.

Lets hope this verifies so we can see the results. I cant recall when a day 5 fax last verified!!

Yep just for clarification on this

The 0z ECMWF det keeps the dew points sub 30F for almost the whole of the UK up until +198 (there's a couple of 6-12 hour spells south of the M4 where they hover between 30-35F)

The colder air is modelled to put up so much of a fight on this run that any frontal precip during is period is modelled to stay south and west of a line from North Wales to IOW - the snow risk across E Scotland and NE England tomorrow needs to be watched with the ECM backing the 6z NAE

SK

Edited March 17, 2013 by snowking

[Purga]

Reasonably chilly to start April

A bit too mild by day

But a chance of some frost at night

Will April follow on from March?

[Captain Shortwave]

NASA model T120 still cold in the North East half of the country and quite a mass of cold air lurking in Scandinavia.

Frontal system pushing North East affecting South West England/Wales and Southern Ireland. Turning to snow