Model Discussion And Chat 19th Feb.2012

[johnholmes]

An overall assessment of the UK weather this morning is that the upper flow, for the next 2-3 weeks, is going to be west to SW most of the time, briefly into west to NW. The upper ridge centred SW of the UK mainly with little if any sign of it moving NE and equally not much suggestion of it moving NW. From the 30mb temperature indicator (falling and already below the average line), through the AO and NAO (both generally +ve), the MJO in phase 2 and predicted to go, in a somewhat wider orbit from the origin for a time, so that may have more effect on developments than when close by the origin=my view only!), through 3 to 4 to 5 and none have any upper ridge shown other than south or SW of the UK, down to the 500mb anomaly charts, not all that similar at times nor very consistent, but all 3 suggest a flow west to SW rather west to NW most of the time at 500mb.

All this would suggest becoming more unsettled at times even further south, although it’s unlikely to give all that much relief to the drought areas. Brief temporary colder shots, chiefly for the north behind travelling lows, these mainly staying north of the UK. Fairly windy at times in the NW close by these lows. Temperatures most of the time around to a bit above normal, briefly below chiefly in the north and overnight in the south in any clearer slots when high pressure is close by.

[bluearmy]

big difference at day 10 between naefs and ecm mean. i suspect the ecm 12z suite to be a 'rogue' run wrt the troughing over our lattitude. would be nice if it were to verify but methinks the mid lat high ridging to our ne from our sw will be more likely come tomorrows ens runs from ecm.

The 00z ECM ens mean hasn't come back too far from yesterday's 12z run and gefs 00z shows signs of heading in the same direction. Figures of 15 and 20 percent now cropping up on the London snow risk post the 7th. Naefs looked solidly against such a solution yesterday and has consistently been generating mid lat blocking for many days. Will be worth monitoring to seeif it begins to pull back somewhat over the next couple runs.

[Thundery wintry showers]

Current outputs suggest a real taste of spring for many of us around Tuesday-Thursday as the ridge of high pressure extends up from the south- plenty of sunshine coming through for most after a cloudy Monday and temperatures getting up to around 14-17C. However western Scotland, Ireland and Cumbria often hold onto grey drizzly weather in this type of situation so it won't necessarily be good "outdoors" weather everywhere. Still no real sign of anything colder but perhaps a change to a more unsettled pattern after the back end of next week, and indeed some evidence of high latitude blocking on the latest ECMWF runs, albeit well out at T+192 onwards.

[cooling climate]

Looking at the 06z GFS run comming out and it looks to me as though the ECM is the odd

one out with it overplaying the energy in the north Atlantic at t144. The GFS and UKMO

hold low heights further west allowing ridging to extend further north. I am of the opinion that

we are indeed a step closer to perhaps a much colder spell around the start of the second

week of March or soon after.

[cooling climate]

For winter weather lovers needing a fix GFS pertubation No 17 is worth a look for great

winter weather synoptics and for something to dream of for next winter maybe.

Synoptics like these would certainly deliver the goods even in early to mid March but the

chance of anything this cold or wintry verifing is probably less than 1%.

[bluearmy]

For winter weather lovers needing a fix GFS pertubation No 17 is worth a look for great

winter weather synoptics and for something to dream of for next winter maybe.

Synoptics like these would certainly deliver the goods even in early to mid March but the

chance of anything this cold or wintry verifing is probably less than 1%.

just posted the same thing on TWO CC. looking thru the runs, i'd say a 15 to 20% chance of that scenario developing. i think chances slowly edging upwards in the period post 7th march. however, i agree there is more than an 80% chance of it not happening to place it into context. the nwp is certainly struggling a bit trying to resolve the amplified ridge around day 7 with the surge of energy off the atlantic soon after and then another ridge off the eastern seaboard after that.

[Summer Sun]

GFS 06z is high pressure dominated

http://www.null/ds/gfs.htm

[MP-R]

A very anticyclonic 06Z, much more so than previous runs and it goes against the idea of a pattern change with more Atlantic influence from a northwesterly direction.

Not model related but does anyone know when November-now will be available on the chart archive? Thanks.

[KTtom]

Looking at the 06z GFS run comming out and it looks to me as though the ECM is the odd

one out with it overplaying the energy in the north Atlantic at t144. The GFS and UKMO

hold low heights further west allowing ridging to extend further north. I am of the opinion that

we are indeed a step closer to perhaps a much colder spell around the start of the second

week of March or soon after.

Thats the great thing about this forum its all about opinions...and for what its worth I agree and dissagree with the post, it does look more and more likely that pressure will build to the NE, however, to me, if it does then that will kill off the remaining chances of any meaningful snow for the rest of the season as we sit in no-mans land and all chances of a norhterly gone.

Personally i'm hoping for ECM/yesterdays GFS to be correct.

[Frosty.]

The Gfs 06z op run is completely out of sync with all the other output with it's anticyclonic 16 days ahead, the latest meto is predicting unsettled weather for the north and west, occasionally extending further south and east, no snow but a risk of frost at times in the more settled spells. I'm going to treat the 6z as a rogue run unless it gathers support and if it does, it just adds more pain to the drought hit south/southeast.

[nick sussex]

Thats the great thing about this forum its all about opinions...and for what its worth I agree and dissagree with the post, it does look more and more likely that pressure will build to the NE, however, to me, if it does then that will kill off the remaining chances of any meaningful snow for the rest of the season as we sit in no-mans land and all chances of a norhterly gone.

Personally i'm hoping for ECM/yesterdays GFS to be correct.

I'd agree with this, yesterday evenings 12hrs ECM run was a much better route forward for some interesting weather, not desperately cold but you'd get some wintry showers and eventually some snow with good convection and some alleviation of the drought for southern areas.

It's hard to see a northerly occuring even with the ECM but a ne flow could have moved in as the troughing sunk into Europe, high pressure over Scandi but orientated unfavourably to deliver real cold to the UK would just eat up any remaining chances for cold and wintry conditions for the UK.

[Frosty.]

GFS 06z is high pressure dominated http://www.null/ds/gfs.htm

Yes but unlikely to verify although it's a nice run for the whole of the uk for a change, so often the north and west misses out on the fine weather but this run is all inclusive for above average sunshine totals and barely a trace of rain for the areas in need.

[Alex95]

The GFS 6z has a brief Scandi high which keeps the Atlantic at bay, allowing the Azores high to push NE'wards over the UK. The ECM from this morning doesn't, allowing cold zonality in, and probably a few decent gales as well. The GFS almost gets there with some unsettled weather, but as I said a brief rise in pressure over Scandinavia allows high pressure to remain in control for Western Europe.

Lets see what the 12z has in store, I'd like some more interesting weather please!

[shadowfax]

It would be great if the GFS at 192 hrs verified, it would give a good covering to the snow starved North West, but I am sure it's unlikeley.

[Summer Sun]

After a quick cold blip

http://www.wetterzen...s/Rtavn1861.png

http://www.wetterzen...s/Rtavn1921.png

http://www.wetterzen...s/Rtavn2161.png

High pressure makes a swift return

http://www.wetterzen...s/Rtavn2401.png

http://www.wetterzen...s/Rtavn2641.png

http://www.wetterzen...s/Rtavn2881.png

http://www.wetterzen...s/Rtavn3121.png

Then at the end of FI cold air arrives in spring and not winter (It will most likely be gone by the 18z update mind)

http://www.wetterzen...s/Rtavn3722.png

Edited February 26, 2012 by Gavin D

[Alex95]

Well, the 12z is an improvement. It looks fairly similar to the 6z overall, but the Atlantic has slightly more energy, allowing a low to slide SE across the UK introducing cold NW'lies. Western Scotland could see snow from the +180 chart, as could Cumbria and hilly parts of Northern Ireland. The reliable timeframe is very boring, not much to talk about really apart from +10°C 850s on Tuesday morning, and I suspect somewhere in the E / NE could come close to the UK February record as we would have done last Thursday if it wasn't for those gales.

Deep FI looks boring with slightly below average temperatures, but I'll not bother saying anything more.

Edited February 26, 2012 by Alza 2

[cooling climate]

The 12z GFS brings the chances of a decent east/northeasterly a step closer while the UKMO

looks a lot less keen at t144, although I do not have a lot of faith in what the UKMO shows at

that range. Lets see what the ensembles and the ECM 12z has to say.

[Alex95]

The 12z GFS brings the chances of a decent east/northeasterly a step closer while the UKMO

looks a lot less keen at t144, although I do not have a lot of faith in what the UKMO shows at

that range. Lets see what the ensembles and the ECM 12z has to say.

I think the only way we can get cold from the continent in this current setup is a SE'ly, and I really don't want that as it'll be dull and dry and cold like the last cold spell. Its quite unlikely anyway, but I know I'd far rather a stormy Atlantic spell even if it means snow is restricted to northern hills. At least I'd have the option of going for a walk in the snow then! I think the GFS is the closest to keeping us under high pressure throughout, so I'm hoping the ECM shows the Atlantic ploughing through by +180!

[Cloud 10]

ECM quite consistent in wanting to drop a cold trough down over the UK from day 7 onwards.

Tonight's 12z looking like following the ECM mean.

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2012022612/ECH1-192.GIF?26-0

This + the Berlin ENS from the 12z sees the prospect of a cold blast from the east possibly becoming a reality

S

[Methuselah]

The 12z GFS brings the chances of a decent east/northeasterly a step closer while the UKMO

looks a lot less keen at t144, although I do not have a lot of faith in what the UKMO shows at

that range. Lets see what the ensembles and the ECM 12z has to say.

TBH CC, I don't have much confidence in any of them, at that range...

[Cloud 10]

Some interesting stuff from ECM this evening,and looks like a repeat prescription on the way

if the +240 came off.

[Tim Bland]

ECM is the best run I have seen for weeks. A cold east / north easterly in FI and low pressure to the south. If only it were Jan, this place would be buzzing!

[I remember Atlantic 252]

last chart looks like a SW'ly to me, for my area

[Cheese Rice]

The last chart on the ECM would provide heavy snowfall via a stalling front which would retreat as the block holds strong.

Anyway positive signs again on the models. I've been pushing height rises over the North East for well over a week now and it looks like we may finally be seeing something more concrete with the ECM jumping firmly on-board. GFS for a time was pushing height rises but it had a wobble and dropped heights now only to push the solution again.

Anyway despite positive signs its a hard setup to strike gold in. We only need to look at the end of last jan or feb 2011 to see how its really quite hard to get a low pushing north over the Med.