Model output discussion - proper cold spell inbound?

[georgiedre]

I for one am hoping that the models show a few low pressures coming in to the SW as an easterly is very dry here on w Wales coast. I'm thinking the high might be further NW than first thought. (Hoping and wishing) ,??

[jules216]

Its about time that pesky NAO went negative,unfortunately its  one month too late for my liking, I hate cold start of spring as much as mild Christmas 

[karyo]

3 minutes ago, jules216 said:

Its about time that pesky NAO went negative,unfortunately its  one month too late for my liking, I hate cold start of spring as much as mild Christmas 

Do you prefer a cold end? lol

[jules216]

15 minutes ago, jvenge said:

Hard to spot the difference between the 0z and 06z mean anomalies.

Hi jvenge,do you have a link to those ensemble maps by any chance,or is it under paywall?

[jvenge]

1 minute ago, jules216 said:

Hi jvenge,do you have a link to those ensemble maps by any chance,or is it under paywall?

Paywall.

 

[Man With Beard]

1 hour ago, frosty ground said:

Looked at the first 10 GEFS and at least 3 of them draw up a south easterly flow from Greece...... Feb 2005 ish

 

That is the one big big risk. Not only do heights in the north need to establish ... heights from the south need to keep out too.

In addition to the scenario you pose here, another spoiler could be a stalled low to the NW of Iberia. If it happens and stalls, heights are promoted on the east flank and we eventually become mild (even warm). If it slides eastward ... get the snow ploughs out.

[jules216]

7 minutes ago, karyo said:

Do you prefer a cold end? lol

I would prefer snowy December, then crispy sunny cold January and gradual moderation by mid. February if I have to be picky. It would be quite challenging for elderly if the coldest weather of winter would carry on throughout March, though  I wouldn´t mind one proper period of lying snow here for the atmosphere, preferably on a Saturday to make the most of it, not a rush hour zonal shower at 5PM on Tuesday as per usual standard of 2014-2018 winters

[Purga]

Cracking 06z ENS!

BTW don't overlook NAVGEM this morning...

Edited February 13, 2018 by Purga

[bobbydog]

19 minutes ago, bobbydog said:

erm thats not correct. the operational run is the unaltered high resolution run. the control is the same but with lower resolution. the ensembles are lower res but with small changes to starting conditions. if the control differs to the op, this determines that the differences in the ensembles are due to lower resolution rather than starting conditions.

if that makes sense....

in fact, let me simplify this further. bearing in mind, the ensembles are a low res version of the op, with tweaked starting conditions, think of the control as just another ensemble but without the tweaks. so basically a low res version of the op.

[Badgers01]

57 minutes ago, tight isobar said:

Running through p-stamps..and the travel of ens(6z)...-16 upper values will likely rear there heads...as we evolve through suites!!!!

Fair enough we shall see , I imagine that would be as low as theoretically possible ...

[MP-R]

2 hours ago, jethro said:

See that's what I don't get. I live in the mild SW (albeit in one of the colder bits and on top of a big hill) and we've had days this winter where it's barely got above freezing all day, surely that's just standard winter fare, not epic?

I'm not being picky or saying anyone is wrong here (seriously, it's all just pretty blobs to me) but it's one of the things I find most confusing. There's clearly lots of excitement around and I'd love to join in, but if epic is -2/-3c I'm struggling. Perhaps it's an age thing, cold winter weather is harder to come by these days but being older, my brain says 'that's not cold' because I've lived through more properly cold winters.

Hi Jethro. Good points, and I'd say it's a combination of the fact that the 'mild' southwest doesn't really start until darkest Devon and Cornwall (and Somerset/Dorset coast) so low winter temperatures aren't THAT unusual, and also despite frigid uppers, minimum temperatures would be held up by the wind so nothing impressive minima wise. Perhaps the more significant aspect would be the very low maxima, perhaps only 1 or 2 degrees higher. If winds were to fall light with those uppers, minus double digits would be the order. Hope that makes sense.

[Frosty.]

The GEFS 6z mean is majestic..There is a very cold spell on the way if this is anything close to reality and looking through there would be plenty of snow opportunities as well as ice days and severe frosts!!??????❄❄❄❄❄❄❄❄❄❄

 

Ps..the mid / longer range signal is for a greater chance of easterly winds and increasingly very cold weather with snowfall, especially in the east and south with frosty / icy conditions widespread!

Edited February 13, 2018 by Frosty.

[Singularity]

15 minutes ago, Man With Beard said:

That is the one big big risk. Not only do heights in the north need to establish ... heights from the south need to keep out too.

In addition to the scenario you pose here, another spoiler could be a stalled low to the NW of Iberia. If it happens and stalls, heights are promoted on the east flank and we eventually become mild (even warm). If it slides eastward ... get the snow ploughs out.

This is another reason why it's important to get a good movement of deep cold our way via Arctic height rises; a deep cold airmass can act like a hammer blow that squashes LPs on the N side and causes them to stretch out west-east. 

Not something the models are all that good at resolving when the situation arises. The GFS 00z was a pretty good effort for a time though. It also highlighted how retrogression of the HLB may however set up a precarious interlude should there be a break in the deep cold import as the flow changes alignment. Pretty sure the deep cold would soon slam back in though. Getting way ahead of myself here of course! 

[bluearmy]

7 minutes ago, Singularity said:

This is another reason why it's important to get a good movement of deep cold our way via Arctic height rises; a deep cold airmass can act like a hammer blow that squashes LPs on the N side and causes them to stretch out west-east. 

Not something the models are all that good at resolving when the situation arises. The GFS 00z was a pretty good effort for a time though. It also highlighted how retrogression of the HLB may however set up a precarious interlude should there be a break in the deep cold import as the flow changes alignment. Pretty sure the deep cold would soon slam back in though. Getting way ahead of myself here of course! 

This is why I’ve been reminding folk when the resolution of the models drops off. I think it’s ultra relevant in this upcoming reversed set up.

i know people like to post individual ens members to show a spectacular pattern but they really are just for fun beyond their high res. 

[Daniel*]

Out of curiosity @Nick L

What are 2m temps by end of EC I’m sure in winter there would have been widespread ice day(s). I think it’s a bit too late in London for them still very cold however not much above freezing, I would have thought.. 

[karlos1983]

7 minutes ago, Daniel* said:

Out of curiosity @Nick L

What are 2m temps by end of EC I’m sure in winter there would have been widespread ice day(s). I think it’s a bit too late in London for them still very cold however not much above freezing, I would have thought.. 

Thursday 22nd at noon = temps struggling!

https://weather.us/model-charts/euro/england/temperature/20180222-1800z.html

Edited February 13, 2018 by karlos1983

[Hammer50]

The models are saying the cold from about the 20 th so this time next week we will know for sure.

[ICE COLD]

4 minutes ago, Bobby93 said:

BBC lunchtime forecast said becoming milder over the weekend and into next week, surely that is just wrong? 

The BBC Weather forecasts just aren't so good/bullish as they used to be a few years ago.

It will be milder at the weekend and start of next week , it's the second half of next week when it could get potentially (hate that word) cold and not this weekend ?

[John88B]

12 minutes ago, Bobby93 said:

BBC lunchtime forecast said becoming milder over the weekend and into next week, surely that is just wrong? 

The BBC Weather forecasts just aren't so good/bullish as they used to be a few years ago.

The colder weather, if or when it arrives, is meant to arrive towards the end of next week . Then, maybe, becoming progressively colder.

Edited February 13, 2018 by John88B

[Seasonality]

5 minutes ago, karlos1983 said:

Thursday 22nd at noon = temps struggling!

https://weather.us/model-charts/euro/england/temperature/20180222-1800z.html

12pm Central Standard Time on that map so actually 6:00pm GMT. Don't worry, I made the same gaffe myself recently!

[Bobby93]

1 minute ago, Banbury said:

I would say that's fair, Monday is into next week .

Was showing 10c in the south next Tuesday lol.

[karlos1983]

1 minute ago, Seasonality said:

12pm Central Standard Time on that map so actually 6:00pm GMT. Don't worry, I made the same gaffe myself recently!

Doh, cheers for that.

updated: so 2-4C widely 

[mulzy]

3 minutes ago, karlos1983 said:

Doh, cheers for that.

updated: so 2-4C widely 

If we have snow on the ground, that will knock a degree or so off these temperatures.

Whatever, we are still looking at quite a notable wintry period.

Edited February 13, 2018 by mulzy

[MattStoke]

Can't see how the weekend/early next week will be milder with high pressure centre over the UK.

[Weathizard]

Wouldn't bother with those temperature charts at this range, sure it may be 4c but it would feel brutal in any form of easterly at this time of year.

 

Sunshine would bring temperatures up, especially down south as it is only getting stronger as winter progresses, but again with windchill/potential snowcover it certainly wouldn't feel warm.