Spring Model Discussion 18Z 6/3/13 onwards....

[Timmytour]

Local weather after the 10pm on the BBC for London and the SE with Peter Cockroft

yesterday...... "not much change at the weekend"

today.........."looks like winter is set to return this weekend" !!

Strange forecasting really and not at all yesterday what John Hammond was saying on the national forecast

But I suppose anyone looking at the models over the past few days has seen the general theme developing...but as always in the UK, miniscule changes in what the models show can affect large swathes of our islands

[Cheshire Freeze]

We find ourselves, at 192 hrs, projected to sit under an extension of the displaced vortex. Some bitter nights possible here

[Mucka]

Decent NOGAPS. I wonder what the first chart will look like after its upgrade on the 13th?

[Tamara]

No need to go fishing.

http://forum.netweat...3/#entry2375348

Yes, that is polite and friendly I think that the next couple of days are a long time in terms of determining precipitation (snow) possibilities from this weekend into the start of next week

[Cheshire Freeze]

Quite frankly that is a STAGGERING 18z GFS right the way out to the last frame. Thicknesses are below 528 DAM for most of the run and below 522 DAM for a fair percentage of it. Unreal synoptics.

[Jamie R]

Decent NOGAPS. I wonder what the first chart will look like after its upgrade on the 13th?

Probably like this

[pages]

Decent NOGAPS. I wonder what the first chart will look like after its upgrade on the 13th?

New Nogaps is already available called the navgem. Current nogaps to be withdrawn on 13th

[Blizzardof82]

From beginning until end the 18z is cold, spring is a long way off going by this run.

[peterf]

impressive for March output.

[Mucka]

(NAVGEM.) Oh righty thanks, didn't know that.

[Cloud 10]

to Mucka and Cloud 10, Fax charts are the latest thoughts from the senior man so of course they will change as the latest outputs are analysed and acted on. For goodness sake its not catch up its realism. Why or why do we have to have this from folk, sorry to say this and it is not intended as an insult, with little meteorological knowledge.Its a bit like telling an eye surgeon, in retrospect, that you know better than he/she!

Well you dd ask me last night what i thought the fax chart for Monday should be showing,so i

posted the 12z ECM ensemble mean as an answer which now looks like a decent match

for tonight's fax.

Sometimes even eye surgeon's can't see what's in front of them.

[Captain Shortwave]

Awesome run for the South Coast, hopefully most of the precipitation will fall as snow. The later part of the run is a lot better with the Scandi trough taking command. I don't know why I feel a little underwhelmed. But I won't let that spoil the South coast party as hey if that verifies you could get quite a lot of snow. Just post a pic on here. It might add contrast to the grey skies I will probably have here

[Mair Snaw]

Well I for one hope the south get plastered in the white stuff... they have missed out to many times this year.. of course would love a bit up here too but not to much as steep hill to the pub gets very tricky in the snow.

[snowmadchrisuk]

Yes the low some of us were talking about earlier in the SW decides to blow up enough to shove a front across the SW , would be the perfect evolution for some of us , although these things have a habit of diving into France come the time, but there was one time a few years ago when all models even at t-0 showed one of these going in to France but instead it moved NE and effected the whole uk, can't remember the year but it was on my birthday 9th Feb.

[Radiating Dendrite]

Come on guys, there is a time and a place to discuss the met ........ on another thread!

Nice 18z run. Interestingly things have slowly been delayed, so the gfs was a bit hasty a few days ago. To be fair, the current output is a blend of what all major models were showing a few days ago, almost like hi res ensembles!

[SMU]

http://www2.wetter3.de/Animation_18_UTC/114_35.gif

Im running out of posts but I will take the 18z!!!

S

[Panayiotis]

http://www2.wetter3...._UTC/114_35.gif

Im running out of posts but I will take the 18z!!!

S

Not good enough!

[Thundery wintry showers]

For those wondering about convective potential from the easterly, I'm going to pull out the skew-t forecast for East Lothian:

http://www.netweather.tv/index.cgi?action=nwdcskew;sess=

There is a "dry lid" just above the 800hPa level. My feeling is that this cap won't be low enough to prevent a scattering of light to moderate snow showers from breaking out in most central and eastern areas (during the late-February spell, it generally ended up dull and dry when the cap was at 850-900hPa and we got scattered showers and some bright intervals when it was up nearer 800hPa). However, while a sunshine-and-snow-showers scenario looks quite probable, it is unlikely to be anything like late November/early December 2010 when towering cumulonimbus cells were widespread.

[SMU]

TWS why pick east Lothian- thats SE scotland!!- not exactly representative of the convective potential for England-

Is there one for Manston- somewhere like that!! or pick 3 locations.. north, middle & south

Edited March 7, 2013 by Steve Murr

[chris55]

Yes a fantastic run for snow potential for southerners.

All to do with how the low approaching to west/south west is modelled.

If we take the big three at noon on Monday you can clearly see the differences.

GFS

ECM

UKMO

As we can see GFS has the low influencing us, ECM has the low but further south and UKMO just can't be bothered with the low at all!!

Will be very interesting to see where the 00z suite sits, would be nice if the GFS 18z has picked up the correct handling of this.

Lovely!

[Thundery wintry showers]

TWS why pick east Lothian- thats SE scotland!!- not exactly representative of the convective potential for England-

Is there one for Manston- somewhere like that!!

I thought that it was fair enough since the air mass over SE Scotland is set to head south (implying that it will affect England shortly afterwards) and also, this isn't just an England thread.

I can find a projection for London, but London is forecast to be under the front still at that range:

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130307/18/84/sound-London-84.png

[karlos1983]

Yes a fantastic run for snow potential for southerners.

All to do with how the low approaching to west/south west is modelled.

If we take the big three at noon on Monday you can clearly see the differences.

GFS

ECM

UKMO

As we can see GFS has the low influencing us, ECM has the low but further south and UKMO just can't be bothered with the low at all!!

Will be very interesting to see where the 00z suite sits, would be nice if the GFS 18z has picked up the correct handling of this.

Lovely!

B E A UTIFUL infact!

[chris55]

GFS op a bit of an outlier early on, I thought it might be.

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

[bradymk]

TWS why pick east Lothian- thats SE scotland!!- not exactly representative of the convective potential for England-

Is there one for Manston- somewhere like that!! or pick 3 locations.. north, middle & south

think this is what you are after Steve, This is for Manston Kent, assume that is where you are after. edit: meant to put link not image as the image may not be the timeframe you are after

Edited March 7, 2013 by bradythemole

[reef]

For those wondering about convective potential from the easterly, I'm going to pull out the skew-t forecast for East Lothian:

http://www.netweathe...=nwdcskew;sess=

There is a "dry lid" just above the 800hPa level. My feeling is that this cap won't be low enough to prevent a scattering of light to moderate snow showers from breaking out in most central and eastern areas (during the late-February spell, it generally ended up dull and dry when the cap was at 850-900hPa and we got scattered showers and some bright intervals when it was up nearer 800hPa). However, while a sunshine-and-snow-showers scenario looks quite probable, it is unlikely to be anything like late November/early December 2010 when towering cumulonimbus cells were widespread.

The best convection would seem to be likely on Sunday night shortly after the front clears before turning mainly dry, overcast and cold Monday morning onwards as the dry cap you mention forms at 800hPa.

Heavy showers possible here:

But no more than light flurries with this unless we see features in the flow like the NE saw in the last easterly:

Far too dry and stable.

As for southern areas, this is frontal precipitation, so on the skew-t it just shows 'stable' conditions with the atmosphere saturated at the lower levels.

As last time though, radar watching is the way to go, the feature mentioned above that dumped lots of snow in the NE during the last event was completely unforecast. Even the high resolution models missed this until 12 hours out.