winter model discussion Winter Model Discussion 06Z 17/02/13 onwards.

[SMU]

Are you sure Steve?

The BBC Countryfile forecast was very underwhelming even for the SE

Maximum of 4c in London on Friday with hardly any mention of the 'white stuff'!

Very very unlikely-

The UKMO t72 maxima under -4c air is 2c- I doubt we will get to +4c under -11c air.

My post above was for both Ians-

S

[ANYWEATHER]

Are you sure Steve?

The BBC Countryfile forecast was very underwhelming even for the SE

Maximum of 4c in London on Friday with hardly any mention of the 'white stuff'!

Countryfile forecasts always edge on the the wrong side of caution!! TBH I dont know why they bother with this weekly forecast anymore its old and out of date surely internet forecasts are more and increasingly accurate......

[Timmytour]

Very very unlikely-

The UKMO t72 maxima under -4c air is 2c- I doubt we will get to +4c under -11c air.

My post above was for both Ians-

S

Unlikely viewing what we can see......but maybe not viewing what they can see.

Let's hope that what they can see and we can't is also first stopping and then reversing the previous trend of the High sinking south

[Mair Snaw]

Hi Steve can you or anybody else able to tell me how to work out what 2m temps will be from the 850 upper temps. many thanx in advance

Edited February 17, 2013 by bigsnow

[SMU]

You cant directly from 850s-

However- if we get the -11c air with dewpoints ~ -5c & a decent cloud cover I doubt very very much you will get 4c.

Also good point above about what the met O can see- this will obv be Mogreps ENS- so when Ian lands im sure he will give us his perspective- although im sure there will be more snow in the text than the other day....

S

Edited February 17, 2013 by Steve Murr

[Snowman.]

Hi Steve can you or anybody else able to tell me how to work out what 2m temps will be from the 850 upper temps. many thanx in advance

Its not just uppers there is other things such as cloud cover and how strong the sun is.

Im not sure but it go with a 12-13oC difference works. But cloud cover is a more important.

Edited February 17, 2013 by SN0WM4N

[Ian Brown]

Its not just uppers there is other things such as cloud cover and how strong the sun is.

Im not sure but it go with a 12-13oC difference works. But cloud cover is a more important.

I would think 4C is unlikely if uppers are -11, even in late Feb in Central London. 2 to 3 more likely depending on cloud cover.

[swfc]

the countryfile late forecast showed temps in the se of 1-2 dgs for thursday.2-3 in lighter winds friday same area,

[BLAST FROM THE PAST]

We were getting 2/3c max temps very recently in not very cold upper air, a week on I doubt the sun's effects would have accelerated that much so under -11c daytime temps would not be 4c I wouldn't have thought

BFTP

[london-snow]

Anyone have the ecm postage stamps & mean chart please?

Thanks in advance.

[BLAST FROM THE PAST]

Cold feed of the very subsided airmass doesn't usher-in fully from E until passage of the weakenIng front after mid-week.

I doubt it will be 8c though and certainly be surprised if its milder on Wed than Tues...and the areas around were showing a decline...except London...so those 'likes' from RB etc are a bit daft IMO.

BFTP

Edited February 17, 2013 by BLAST FROM THE PAST

[Summer Sun]

Back from watching top gear here is the ECM full ensemble

A definite trend to something milder after a week or so of colder weather precipitation remains very low through-out this week should be dry for most with just the odd snow flurry where the cloud is at its thickest in the east

Precipitation for February is likely to be well below average for many parts

Edited February 17, 2013 by Gavin.

[damianslaw]

Reliable timeframe - very much a blocked set up, and very dry in the main. ECM and GFS are suggesting heights will stay preety low over europe for the foreseeable future which will help to prop up heights to our north. How far north and west these heights will get is the key question. The PV over Siberia is forecasted to spill some energy into NW Russia and it might even develop a shortwave feature to the north of scandi which could help trigger a movement of heights NW in time.

GFS is very keen on developing very strong heights over Greenland as we end the month as a very meredional flow sets up - low pressure steaming out of USA is projected to dig deeply southwards which again is conducive to heights being able to move NW as it removes the influence of the azores high.

Its a very difficult call at this range to start speculating how we might end winter 12/13 any one of the following scenarios is very plausible based on current model outputs -

1. Anticylonic, with heights langushing over the country meaning sunny chilly days and very cold frosty nights, or further to the south meaning milder probably cloudier conditions with rain in the NW.

2. A northerly feed as we see heights build strongly to the NW with low heights to our NE, the northerly becoming a northeasterly.

3. A weak atlantic attack from the SW.

[Hammer]

Ian F and Matt Hugo seem confident on their twitter feeds of cold dry then milder weather based on model output they see. Interesting because in most part they have always been cautious of making calls on weather 7-10 days away.

[Tristrame]

Hi Steve can you or anybody else able to tell me how to work out what 2m temps will be from the 850 upper temps. many thanx in advance

As a rule of thumb,temperature drops a degree every 500ft you rise.So the 850 temps are at 5000ft which means there is a basic 10c difference warmer at ground level.

Other factors come into play that can make it warmer still,like the strength of the sun,length of daytime and a big one is the urban heat island effect in towns and cities.Lying snow making it colder.

Essentially no day and no place under the same 850 upper temp is guaranteed to have a certain 2m temp.

You can be guaranteed though,that -11 uppers on high ground would bring ice days at this time of the year still,I think, and probably to areas with snow cover.

850 upper temps like that are great over a sea track for creating heavy snow showers.

That's my understanding anyhow.

[Severe Siberian icy blast]

I doubt it will be 8c though and certainly be surprised if its milder on Wed than Tues...and the areas around were showing a decline...except London...so those 'likes' from RB etc are a bit daft IMO.

BFTP

To be honest I really don't see the need of this temp debate , the bbc always over prog the temps , i very rarely take the temp prediction seriously until the day before , we have enough information before us to make our own judgment on the temp , but in all truthness I really don't see the need to do make one with something 3 days away.

Nice to see the upgrades today , but it's not a done deal yet , and I think many of us are still hoping for further northward corrections.

Although cant see it myself.

Its nice to see very cold uppers in the mix now, it's one thing that was missing from the models showing within this setup. Which is why I was so adament on advising ones to look past the 850's and concentrate on the Synoptics at the range it was showing.

Hears hoping for an upgrade again . . . . .

[ANYWEATHER]

With the Low dewpoints later this week. fridgid is what I call it ....

[BLAST FROM THE PAST]

Ian F and Matt Hugo seem confident on their twitter feeds of cold dry then milder weather based on model output they see. Interesting because in most part they have always been cautious of making calls on weather 7-10 days away.

Weren't recent tweets of a SW flow as well? hmmmm

BFTP

[Mair Snaw]

Many thanks to those that have taken time to answer my question from earlier. looking forward to the pub run tonight and hope that the shift of the pattern north from the 12z continues.

[bluearmy]

The trend on the 12z ecm suite is no surprise given the op. the euro trough far more of a player towards the end of the week with far more runs squeezing the flow and lifting lower slp numbers into the south of the uk. there are 5 clusters on the postage stamps. Thats normally indicative of not making brash calls on where we're headed. i guess there will be fair anticipation of the 00z runs.

spreads in fi show a cluster of runs must be developing an iberian trough which then pushes ne against our block which in turn is held in place by the ne scandi trough and the jet running well to our south. i guess that would be a fair way of a breakdown with the the direction sw/ne

[bluearmy]

Ian F and Matt Hugo seem confident on their twitter feeds of cold dry then milder weather based on model output they see. Interesting because in most part they have always been cautious of making calls on weather 7-10 days away.

The gefs seem very confident of less cold in week 2. No need for matt to be cautious. One day i see people chastising pros for not making a forecast and are we now going to question them when they do so.

You will find the pros happy to make a prediction based on strong ens trends. What they wont do is back an op when the ens dont agree with it.

[SMU]

I'll try again!

Will a moderator please PM me why you deleted my last post with 14 likes?

did it quote something that someone else posted...?

The gefs seem very confident of less cold in week 2. No need for matt to be cautious. One day i see people chastising pros for not making a forecast and are we now going to question them when they do so.

You will find the pros happy to make a prediction based on strong ens trends. What they wont do is back an op when the ens dont agree with it.

I agree- & how ironic we are currently 0-2 for the ensembles V the operationals in recent times....

[LomondSnowstorm]

OMG I feel like banging my head against the wall sometimes!

How can you state it is going to be dry for most going by a set of ensembles when they don't factor in the following :

~ Showers

~ Disturbances

~ Streamers

These bloody precip charts are only half decent if you are looking for snowfall as a low runs into colder air or something along those lines.

Useless if you're looking for convective potential which we are or soon will be.

Equally even if they could pick up on such convective activity this would certainly not be evident in the De Bilt ensembles off an easterly flow.

[Tim Bland]

Sorry but ensembles, just like operational runs, can pick up on precipitation whatever form it comes in. Showers / disturbances / streamers are all picked up on by the models. I agree that things can pop up at short notice but some people just want to see what isn't there sometimes! We are looking at a mainly dry week under high pressure. A few snow flurries in the south east and east. This is what the experts at the met office, who can see every model that we can and loads more, are forecasting.

Longer term things are looking more promising the evening. At the end of the ECM we still have the high but more interestingly warm air is being advected to Greenland. If this occurs then it Could allow the high to retrogress as pressure rises to our NW. There is some very cold air pouring out of Russia and If we can tap into that then winter cold go out with a bang.

http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=1&type=0&archive=0

This is what I'm looking at in future runs. Not a few flurries in Kent on thurs / fri.

[Snowman.]

Ian F and Matt Hugo seem confident on their twitter feeds of cold dry then milder weather based on model output they see. Interesting because in most part they have always been cautious of making calls on weather 7-10 days away.

I never listen to the tweets the same tweets over and over.

Last week when we had the slider they went against saying gradually return to warmer temps and stuff but that ofc didn't happen.

I would try to avoid them even know they are good but misleading when you can got over 170 characters.