Model Output Discussion - Spring Has Sprung

[Mike Poole]

A perhaps surprisingly cold plunge on the GFS 12z.  At T270, uppers are a quite respectable -6 or below pretty much country wide:

[Dennis]

GFS march

maybe a good idea to make a new TOPIC on what will happen into March?

 Mike Poole the time has come my friend

[ANYWEATHER]

17 minutes ago, Mike Poole said:

A perhaps surprisingly cold plunge on the GFS 12z.  At T270, uppers are a quite respectable -6 or below pretty much country wide:

Given we are on the doorstep of March ,it will be just typical that when we want Spring and warmer weather to come ,these synoptics charts will probably verify even that far out!

[Cheshire Freeze]

I’ve been saying about March for a while…

[daz_4]

 Dennis The time has come for spring to continue  

[Metwatch]

1 hour ago, CoventryWeather said:

The GEM and GFS have been fairly interested at this in the mid range, and the latter certainly been the one recently that makes trends. 

The GEM op this evening wants to blow up this low next weekend and so it ends up staying mild afterwards for a bit longer. If this scenario took place, that would be the mildest February on record fully set in stone.

Other model runs not going for this at the moment, so I think the chance that this February might not be the mildest one is still there. Still very likely to make it into the top 3 / 5 now, especially even if further colder air manages to reach southern England by the end of the month via a more direct northerly. That would stop it from being the mildest on record, but simply not enough to stop it from being an overall very mild month.

Edited February 18 by Metwatch
conciseness

[feb1991blizzard]

 Cheshire Freeze

You have - slight concern is it might be perfect synoptics firing blanks, unless GFS 6z 384 verifies, would be a treat.

[Capri61]

 Kirkcaldy Weather wow !! A lot of information there thanks for that .

Unfortunately though as I am a new to all this not sure what it all means . I am trying to work out if there are any signs of any colder air heading from the East as we head into the end of Winter ?? .

[Uncertainty]

The track of next weekend’s Atlantic shortwave - diving into the base of the already established long wave trough -and upstream amplification, is certainly of interest this evening. Though we’re still at the stage where the modelling is envisaging it in many different ways…
 

Ukmo

The UKMO barely develops it at all and thus the Atlantic ridge is able to push north

 

Icon

The German model does develop the low, but it stays on a thoroughly NW/SE track and the  Atlantic high pushes north anyway

Gfs

Similar to the UKMO, barely develops the shortwave. The northern arm Of the jet really stretches itself polewards on this run. Will need a lot more runs to convince me of this, but there’s clearly a trend here…

 

Gem

The gem does develop the shortwave, this is related to the Azores high pushing into S Europe.

As a result, the Atlantic high fails to push northwards. 

Before today, this had been the favoured outcome on the Atlantic ensembles. 
 

Today’s GEFS does have plenty of members in the op/UKMO/icon camp but equally it has plenty in the gem club. So the mean is only there to represent the bifurcating options

This winter, whenever we’ve had a ‘crux’ like this, the mild /flat option has usually won out. Even if it hasn’t e.g the start of Dec and Jan cold snaps, we haven’t managed a significant lowland snow event. Will this one be any different? 
 

 

 

 

[Purga]

Blimey, it looks like Bournemouth's the place for snow!

[Mike Poole]

 Purga Bournemouth isn’t over there!

[andymusic]

 Purga more Poole/Torquay way

[Jacob]

The ECM could make a blizzard in the SE if it was a tad colder!!

[Purga]

 Mike PooleOK - Bridport then! It's not going to happen anyway as we well know in this abysmal non-winter spring

 andymusic Mike Wantage from Poole told me.

[Ali1977]

ECM on Sunday 

[northwestsnow]

 Ali1977 typical.

4 weeks earlier a different story..

[Uncertainty]

The JMA shows we can still roll snake eyes and end up with this monstrosity:

The ecm op - which over the past few years I have grown to have little faith in - almost makes it with the heights over the top ridging to scandi but, alas, fails miserably. Still, the day 10 chart looks - as well as looking a lot like the strat output - more like the start of something than the end…

 

[WYorksWeather]

GFS just generally wanting to hold temperatures around average at the surface and a little below at the 850hPa level right the way through. Worth highlighting that very few model runs show temperatures touching 0C, so I think the probability of any snow accumulating or staying around for more than brief periods is very low. Central case is probably still for lots of cold rain I'm afraid.

Interesting to note the divergence in temperatures beginning in the charts as soon as day 8 or so. If we look at the spread chart, we can see the uncertainties in the heights are largest over the UK and just to our west, which is pretty unhelpful!

It's also useful to take a look at some of the ensembles individually around that point, so from days 5 to 10.

The GFS mean at days 5, 7 and 10:

Ensemble member P09 (one of the mildest up to day 10):

Ensemble member P18 (one of the coldest):

So, the key differences are generally in pressure over Greenland, and also just out to our west. Where we see more of an extension eastward of the Azores high, there's more of a tendency for the wind to remain closer to north-westerly than northerly or north-easterly. The colder runs are generally developing twin blocks over the far side of Greenland and over the Urals, which then drags in a north-easterly.

I do think a lack of cold to work with is going to be our undoing from a cold perspective, so even if one of the colder options verifies, I don't think we'll see much in the way of wintry weather beyond what is usual for the time of year (hills, possibly brief accumulations to lower levels in the north).

Beyond that, into early March, the spread on the models is clear for all to see - there are plenty of options that keep a fairly cold zonal pattern going, and others that return us to something milder more quickly.

Worth also looking at sea level pressure.

I think it's a case of look away now if you want anything settled (whether cold or mild)! Appalling ensembles those. Stormy conditions around the 22nd-23rd and possibly again around 24th-26th, then a very slow recovery to still likely showery weather to round out February. Into March, we possibly have just the earliest indications that pressure might begin to rise again from the south, so possibly some hints of optimism there. But it's in far FI, and we need that signal to count down to the reliable.

Maybe I should forget spring or winter, and just hunt for the next solid week of dry weather. Might be almost as depressing as hunting for snow...

[TURNED OUT NICE AGAIN]

 Cheshire Freeze Ditto...I think winter will have a sting in its tail

[Mike Poole]

 TURNED OUT NICE AGAIN It may do in terms of synoptics - the concern I have is there is no real cold anywhere near the UK to easily tap into.  GFS managed to draw some in from the far north but that would need some luck to land.  

[Dennis]

forecast to a patternchange

[Ali1977]

Best chance of snow for the entire winter by the end of this week - I mean, if it materialises it actually will be in the south. 

[swfc]

 Ali1977

[Ali1977]

 swfc just need 1 flake and the week wins as the snowiest week of the year - not bad at 800 feet ASL

[Daniel*]

56 minutes ago, WYorksWeather said:

just generally wanting to hold temperatures around average at the surface

I’ll have to correct you 7C maxes is not average in London at end of February the lowest average max is 8.4C in January. The normal in late Feb is 10C. It’s below average evidently if it was January, it would be a bit colder say 5C.