Model Output Discussion 01/09/17

[knocker]

Latest on the possible rainfall

[MattTarrant]

6 minutes ago, Steve Murr said:

A reasonable start to the 18z GFS pushing the colder air further SE at 72-84

Looking for some potential mild V cold interaction along the wave @96...

This run doesn't develop the wave feature as much so no sign of any leading edge snow (If any limited to the highest ground in Wales). Sure not to be settled on however for at least another 24hrs.

[swfc]

Seem to have lost our trigger low tip of greenland 138hrs on gfs 18z???

[I remember Atlantic 252]

3pm Sat, most favourable for snow chances here, cold air reach the SE a bit later

[Geordiesnow]

9 minutes ago, MattTarrant said:

This run doesn't develop the wave feature as much so no sign of any leading edge snow (If any limited to the highest ground in Wales). Sure not to be settled on however for at least another 24hrs.

Personally I rather this mess of a set up for Friday does not occur because the air is just simply no where near cold enough for snow apart from the top of the hills, yesterday's output had a nice clean airflow heading into the UK, todays output is now showing this shallow low and all it does is delays any cold from the North West and deliver a lot of cloud and rain, only the ECM kind of keep it well to the South but even this model has backtracked slightly.

[Jonan92]

In this run there is no shortwave transitioning to our side and bringin the cold to the south

[I remember Atlantic 252]

12 hour window on this run, 3pm Sat to 3am Sun, for Cheshire Gap snow, conditions become unfavourable early Sun am

[blizzard81]

Fax charts have updated. The 528 dam into northern France by 12pm Saturday. 

[winterof79]

2 minutes ago, Jonan92 said:

In this run there is no shortwave transitioning to our side and bringin the cold to the south

The colder air is actually further south than the 12z

 

[northwestsnow]

Just now, blizzard81 said:

Fax charts have updated. The 528 dam into northern France by 12pm Saturday. 

Yes that ties in with the BBC forecast earlier.:)

[MattTarrant]

2 minutes ago, Geordiesnow said:

Personally I rather this mess of a set up for Friday does not occur because the air is just simply no where near cold enough for snow apart from the top of the hills, yesterday's output had a nice clean airflow heading into the UK, todays output is now showing this shallow low and all it does is delays any cold from the North West and deliver a lot of cloud and rain, only the ECM kind of keep it well to the South but even this model has backtracked slightly.

I agree with the begins of your statement, the length of source is too high for there to be sufficient cold for there to be snow down to low levels. Unless there is a perfect combination of undercutting cold air and adiabatic cooling (Unlikely). With regards to the latter of your points, the front actually clears sufficiently to allow respectable uppers for a North West flow (Though still not enough for snow anyway from areas with reasonable height).

[winterof79]

3 minutes ago, blizzard81 said:

Fax charts have updated. The 528 dam into northern France by 12pm Saturday. 

 

[Cheshire Freeze]

There will be another attempt at a block into FI as the cold spilling off the ESB is reduced on the 18z

[swfc]

3 hours ago, swfc said:

Not to put a dampner on things but ecm looks at the extreme end ie blocking ete.imo lookiing at today's output id be looking at good Atlantic block pushing north with the pv dropping well to the east

Cool-cold with frosty dry weather after the weekend.good output going onto winter nonetheless

 

.

Not a million miles off ie 18z. On to tom and all change im guessing

[lorenzo]

ECM doesn't have this play from 144 - 168.

GFS this evening providing no further clarity, think it will take 12zs tomorrow to dial in on solutions.. Delighted with what is shaping up presently-  new territory on wave activity and a general feel of a winter with some action. Disconnect, rock solid QBO and Nina/ Nada / Nino subtle in their nuances thus far.

If we get a 'stuck' pattern of cold shots then bring it on... 

[tight isobar]

Just 1 more run/one more variation.

Still good...

But more to be resolved.

 

[knocker]

23 minutes ago, swfc said:

Seem to have lost our trigger low tip of greenland 138hrs on gfs 18z???

These are actually wave depressions forming on the front, you can see the trough on the 500mb chart, and one does track east to be Ireland by T162

[feb1991blizzard]

19 minutes ago, CreweCold said:

There will be another attempt at a block into FI as the cold spilling off the ESB is reduced on the 18z

At t234, if it wasn't for that small low on the SW tip of Greenland, we could have ended the 18z run with a 17th Dec 2010 level of potency Northerly, its stopping that high in the Atlantic from a full on retrogression to Greenland.

 

As it is, its non too shabby, not perfect but better than this upcoming weekends feeble attempt with much better uppers.

Edited November 20, 2017 by feb1991blizzard

[booferking]

Guess what it's the weekend again.

[blizzard81]

4 minutes ago, feb1991blizzard said:

At t234, if it wasn't for that small low on the SW tip of Greenland, we could have ended with a 17th Dec 2010 level of potency Northerly, its stopping that high in the Atlantic from a full on retrogression to Greenland.

Don't worry, that low zips down to introduce the beast from the north. 

[Mucka]

3rd time lucky

[blizzard81]

Pub run special. Oh we have missed you

[tight isobar]

Further highlighting the variants/divergence..

Northern hemisphercaly a world apart!!

Also placements off the scale...

Its going cold....just how cold...???

All options open atm!!!

18z

12z

Edited November 20, 2017 by tight isobar

[Cheshire Freeze]

Well would you believe that, the block has another go in FI 

;-)

[JeffC]

52 minutes ago, knocker said:

Latest on the possible rainfall

Don't like the look of that for my patch...looks like one of those atmospheric rivers....again!