Model Output Discussions 18z 31/01/2016

[Severe Siberian icy blast]

Ignoring specific details I just wanna point out how nice it is to see an abundance of high lat blocking moving forward 

quite a strong -AO setting up there for next week and in a fairly good position to advert deep cold air south into Europe and gives us a fairly good opportunity for further cold and snow events to manifest themselves . 

I have a sneeky feeling that the strat warming is beginning to manifest itself into the models and maybe it isn't a complete flop like everyone on the strat side of things thought so ? 

Or if it is trop led then that's 2 major trop led -AO signatures we'v managed to achieve without the strat giving us a helping hand .

Either way I think the second half of Feb is beginning to look interesting . 

Im gutted this weekends snow has miserably failed by the looks but at least things don't terrible moving forward .

lets see how this all pans out 

[fergieweather]

33 minutes ago, snowangel32 said:

Just seems like a big call at still a week away there is still big uncertainty over the eastwards progression of the front. And the express will jump all over this. They are normally so cautious so a big call they must have high confidence in this, we shall see.

I've just discussed this Tweet with our duty forecaster. It actually refers to the 'Weather for the Week Ahead' forecast (video on the webpage, but wasn't linked in the tweet). Framegrab below from raw 00z UKMO-GM (Weds night) for reference: i.e., tying with UKMO broad notion of possible snow issues parts of central UK depending on retrogression of the Scandinavian high and resultant slowing/stalling of front(s) from W/NW. We aren't going to go big on this at the moment. It's just an early heads-up that this issue might become a problem for travellers etc next week. Hope that explains.

At ease, folks.

[nick sussex]

The UKMO looks colder at T96hrs than the GFS.

Should be some convection off the North Sea for favoured areas. Also another new trend is to re-amplify the upstream pattern and separate the trough near the UK. It was originally one feature but at T144hrs you can see it splitting in response to the amplification upstream which pulls it apart.

Because of this re-amplification theres a better chance that you'll see that trough disruption through the UK as that deep eastern USA low heads east so the GFS trend doesn't look out of place given the upstream pattern.

In terms of the MJO the amplitude continues to increase especially in the ECM which was reluctant to do so a few days back. I think the MJO is part of the reason we're seeing this upstream re-amplification.

 

 

[mushymanrob]

i wouldnt start to believe the gfs just yet, i dont think the noaa anomaly charts allow for such a run the gfs is currently suggesting for mid next week, although something like it might occur for upto 48 hours, nothing like the evolution the gfs suggests for longer is likely. of course tonights noaa charts might change,,,

[feb1991blizzard]

6 minutes ago, Severe Siberian icy blast said:

I have a sneeky feeling that the strat warming is beginning to manifest itself into the models and maybe it isn't a complete flop like everyone on the strat side of things thought so ? 

Or if it is trop led then that's 2 major trop led -AO signatures we'v managed to achieve without the strat giving us a helping hand .

Either way I think the second half of Feb is beginning to look interesting . 

 

Either way, if the very strong Strat warming at the very top in GFS FI manifests itself for any length of time it would surely disrupt the vortex further down at some point and a very blocked March certainly wouldn't be out of the question, ive just got a really niggling feeling though that we will get a massive long fetch Easterly in March at some point but wont have any cold air to tap into!!

[SMU]

So here is the JMA 84

i believe if I was challenged to make a forecast in terms of 500 heights & where the 850s are this would be my best punt for Monday-

Sleet & snow flurries penetrating a way in land - more persistent in the E/NE & SE

the flow is a classic kent streamer ( not thames ) so places like bluebell may get a covering

the -6c@ 850 is clearing the south coast..

also the wave of high pressure in atlantic is subsiding away from the high over iceland which is great as we dont want them linked

notice the energy seperation of that deep low in the atlantic signalling a split flow

i would hazard a guess tonight JMA may well be the top run....

 

S

 

 

Edited February 11, 2016 by Steve Murr

[snowice]

3 minutes ago, Steve Murr said:

So here is the JMA 84

i believe if I was challenged to make a forecast in terms of 500 heights & where the 850s are this would be my best punt for Monday-

Sleet & snow flurries penetrating a way in land - more persistent in the E/NE & SE

the flow is a classic kent streamer ( not thames ) so places like bluebell may get a covering

the -6c@ 850 is clearing the south coast...

 

S

 

 

U mean lake effect snow? Cold uppers over warmer sea?

[nick sussex]

NCEP medium term discussion:

OVERVIEW... MODELS CONTINUE TO DEPICT A LONGWAVE TROUGH REMAINS IN THE EASTERN NORTH AMERICAN CONTINENT WHILE A LONGWAVE RIDGE WILL GIVE WAY TO AN UPPER-LEVEL TROUGH ARRIVING AT THE WEST COAST BY DAY 7/THU NEXT WEEK. THE MOST NOTABLY FEATURE THROUGH THE MEDIUM-RANGE PERIOD IS A LOW PRESSURE SYSTEM TRACKING UP THE EAST COAST FROM DAY 5/TUE TO DAY 6/WED. THE TREND HAS BEEN FOR A MORE INLAND TRACK RATHER THAN A COASTAL TRACK.

The inland track is because of the increase in upstream amplitude, this will pull the Azores high further nw and help to disrupt energy se in towards the UK.

I should add this mornings ECM 00hrs run was discarded after day 4 for being too fast and flat, you'll see it runs that low quickly east and phased it with the PV over Greenland.

Given both the GFS and UKMO have moved to increase the amplitude upstream and NCEP have noted this trend then the ECM could be facing 3 epic fails in one week if it doesn't backtrack this evening.

 

Edited February 11, 2016 by nick sussex

[marksiwnc]

Just now, fergieweather said:

I've just discussed this Tweet with our duty forecaster. It actually refers to the 'Weather for the Week Ahead' forecast (video on the webpage, but wasn't linked in the tweet). Framegrab below from raw 00z UKMO-GM (Weds night) for reference: i.e., tying with UKMO broad notion of possible snow issues parts of central UK depending on retrogression of the Scandinavian high and resultant slowing/stalling of front(s) from W/NW. We aren't going to go big on this at the moment. It's just an early heads-up that this issue might become a problem for travellers etc next week. Hope that explains.

At ease, folks.

Ian all the models are showing colder than predicted weather for next week and what we have seen since mid January is for high pressure to push further West and strengthen.  Do you think the front for nxt Wednesday /Thursday  could end up a nothing and only southwestern parts seeing any precipitation if it's rain or snow.  We don't know.  What's the chances of this happening?? 

[Man With Beard]

 

4 minutes ago, marksiwnc said:

Ian all the models are showing colder than predicted weather for next week and what we have seen since mid January is for high pressure to push further West and strengthen.  Do you think the front for nxt Wednesday /Thursday  could end up a nothing and only southwestern parts seeing any precipitation if it's rain or snow.  We don't know.  What's the chances of this happening?? 

I know this is aimed at Ian but can I butt in - this kind of trough disruption is traditionally the hardest thing to pinpoint. Do not take any positioning of fronts literally until 3 days before the event. At best!!

[Banbury]

6 minutes ago, Man With Beard said:

 

I know this is aimed at Ian but can I butt in - this kind of trough disruption is traditionally the hardest thing to pinpoint. Do not take any positioning of fronts literally until 3 days before the event. At best!!

Exactly ,not even worth considering yet

[Man With Beard]

Honestly snow fans, this is the time to scream at your computer. T72 - channel low, good easterly feed, a well defined low - how on earth can this not result in snow for central England!!!!

 

[bobbydog]

21 minutes ago, marksiwnc said:

Ian all the models are showing colder than predicted weather for next week and what we have seen since mid January is for high pressure to push further West and strengthen.  Do you think the front for nxt Wednesday /Thursday  could end up a nothing and only southwestern parts seeing any precipitation if it's rain or snow.  We don't know.  What's the chances of this happening?? 

its about 50/50. though there's only a 10% chance of that...

[Frosty.]

Next week looks potentially exciting for snow starved coldies according to these Gfs 12z charts and some very frosty nights, especially at the end of next week...hopefully this hopeless winter is about to deliver what most of us have been crying out for....SNOW!

[fergieweather]

26 minutes ago, marksiwnc said:

Ian all the models are showing colder than predicted weather for next week and what we have seen since mid January is for high pressure to push further West and strengthen.  Do you think the front for nxt Wednesday /Thursday  could end up a nothing and only southwestern parts seeing any precipitation if it's rain or snow.  We don't know.  What's the chances of this happening?? 

Currently unfathomable re outcome detail. Much depends next week on degree of retrogression by high to NE and how long the colder air lingers in E/SE. The suspicion has always been for slower(ish) return to W'ly progression than billed in operational output (models lean too quick with breaking-through this sort of gig, usually); then (as per repeated GloSea5 runs) a temporary phase of stronger zonality last week of Feb (but with colder NW'ly bias returning and +ve MSLP to west), before signs of hopefully more settled/drier developments on into early March (with MJO phase 6 favouring -ve NAO). 

Edited February 11, 2016 by fergieweather

[snowice]

ECM 144 -7uppers  over Eire upgrade on the way

[Ali1977]

1 minute ago, fergieweather said:

Currently unfathomable re outcome detail. Much depends next week on degree of retrogression by high to NE and how long the colder air lingers in E/SE. The suspicion has always been for slower(ish) return to W'ly progression than billed in operational output (models lean too quick with breaking-through this sort of gig, usually); then (as per repeated GloSea5 runs) a temporary phase of stronger zonality last week of Feb (but with colder NW'ly bias returning), before signs of hopefully more settled/drier developments on into early March (with MJO phase 6 favouring -ve NAO). 

Quite a nice outlook for coldies - drier will also please many. I'm hoping what GFS is showing for next Fri verifys giving us some snow first.

[fergieweather]

2 minutes ago, Ali1977 said:

Quite a nice outlook for coldies - drier will also please many. I'm hoping what GFS is showing for next Fri verifys giving us some snow first.

The overall outlook remains for broadly average to slightly colder than average conditions rest of Feb, but with risk of colder weather tending to rise later, commensurate with increased likelihood of NW'ly flow.

[feb1991blizzard]

2 minutes ago, fergieweather said:

The overall outlook remains for broadly average to slightly colder than average conditions rest of Feb, but with risk of colder weather tending to rise later, commensurate with increased likelihood of NW'ly flow.

Ian you say -NAO for March, Are there any Glosea5 ens members showing Northern blocking in march and is there likely to be an abrupt reversal of u-winds in the stratosphere?

Edited February 11, 2016 by feb1991blizzard

[chris55]

Lots on offer it seems, models are certainly full of interest at present!

Saturdays Low will hopefully just miss us altogether ha. And then once the proper cold air is in we can start looking at some snow potential.

[nick sussex]

The ECM is still the flattest solution at T144hrs for the eastern USA. Both the GFS and UKMO have more dig south of cold into the eastern USA at that timeframe.

NCEP will update their State discussions later so will have more on what they think then.

The ECM isn't a bad run upto T168hrs but its still taking a lot more energy ne rather than se.

 

[kent]

ECM has low hitting  Wed to Thurs. next week but im not convinced about those uppers.

[SMU]

Evening

 

last one from me - The JMA as i hinted at earlier - also alligned to the JMA 132 V UKMO 144 identical & goes on to produce a great run with snow & probable ice days in England...

also a nice wedge of -10c air developing in situ....

 

S

Edited February 11, 2016 by Steve Murr

[Frosty.]

Yes the JMA 12z turns into a peach of a run for coldies, would like some of that!

[Man With Beard]

A closer look at Sunday on the ECM, courtesy of the Icelandic Met:

Precipitation over all of southern England (moderate in SE). -5C 850s on the northern edge, and bear in mind on an easterly, not westerly. This is 6pm, so nightfall. Got to be a good chance of snow on that.

(and many northerners I'm sure will easily get snow showers at some point over the weekend, too)