Model Output Discussion - Spring Has Sprung

[TillyS]

I’m off to Norway next week in search of proper snow, though I have to confess I’d really like a Scandi high to build so I’ve a chance of seeing the northern lights. Not much sign of it in the outputs but they’ve had a cold winter in Scandinavia so there should be plenty of snow around.

This upcoming cooler spell is a reminder that Spring is not here yet and it may pep things up for the Scottish ski industry. It was pretty sad this past week seeing the briefly white mountains return to drab brown. Still beautiful, but I love the snow-scenes best.

Edited February 21 by TillyS

[Weather-history]

 Methuselah

Did January 2019 SSW amount to nothing?  Occurred 2nd January 

 17th Jan-3rd Feb 2019 CET: 2.2°C  

[RJBingham]

 Weather-history didn't it lead to the warmest February day ever recorded? 

[Weather-history]

 RJBingham

Did it, though? 

We know three things

There was a SSW around the 2nd January 2019

The second half of January 2019 and the start of February 2019 was the cold wintriest part of that season.

There was record warmth during late February 2019

[keithlucky]

Again big strat warming on the way .Zonal reversal happeng mid March ,a bit of relief to finally see us in UK dry out.

[Nick2373]

hopefully we'll see the ppn spikes drop a dryer warmer spring like conditions showing on the 00z 

[bluearmy]

The early March reversal is consistently modelled as a strong reversal.  this is where it differs from the last two. Infact the last one and one just finished verified as very brief tech reversals and only really picked up about a week to 10 days ahead in the ens.  The early March has been signalled across the eps and gefs at two weeks out (more by the 46). 

The difference also showing on this next one is that there looks to be no appetite for any recovery back to positive  (which previous two forecast reversals showed). The time of year obvs relevant here. 
 

finally, the gfs ops (which is all we see at this range ref downwelling ) are keen to bring this reversal right down into the lowest levels of the strat and towards our latitude. That should mean the trop feels some effects fairly quickly. 
 

the ext ens look like they want to really build that scrussian ridge - becoming sceuro.  In tandem with some high anoms west Atlantic and a ‘trough’ wnw of Iberia this is how a neg NAO could manifest for march.  

[Ladyofthestorm]

Remind me of late winter Early spring 2020. 

 @Weather-history  I'm sure lockdown part 1 was a pleasant meteorological affair ? 

Edited February 21 by Ladyofthestorm

[Cambrian]

The Iberian heights taking a bit of a late season pasting at the hands of the polar trough during the next few days (these are all for 0-84h) on 0z GFS op…

 

…in more ways than one. 

  

With the 528 thickness line briefly grazing the north of Spain and the freezing level at 800 - 1200 metres, heavy falls of snow for the Cantabrian Mountains, which reach up to over 2000 metres.

Closer to home, with those kinds of thicknesses that far south, falling snow is a very reasonable possibility anywhere in the UK and Ireland. Freezing levels often near 400 metres, sometimes a tad lower in the colder pockets of polar maritime air bustling through, so upland Scotland doing very well for settling snow, and scope there for slight accumulations at times for parts of Central Wales and Central England too, as well as local accumulations more widely no doubt. The GFS has been consistent with the modelling of these thicknesses, freezing levels and precipitation for several days now, as it has been with this morning’s deluge!

Whatever falls out of the sky and whether it sticks, for everywhere in Western Europe a very different feel to the end of the week. Have a great day. 

[Jordan S]

Gfs showed a big adjustment to Sundays low pressure system at short timeframe this morning with the orientation and location over the North Atlantic,  has brought the low slightly north as expected so Sunday is looking wet again for many southern areas of England and Wales, hill snow for Wales likely. Not a certainty and could remain to our south but unlikely I think.

previous update..

This morning’s..

The persistence of the rain and orientation of the fronts over southern UK on this Gfs update reminds me somewhat of storm Alex a few years ago October 1st 2020 I think, though unlikely to be anywhere near as wet as during that system.

Rainfall totals look to be around 10-20mm widely, locally a bit more, but a small chance of around 50mm widely and around 80mm locally, local snow accumulation on hills of Wales a possibility.

Beyond this once again taking a look at last couple days of Feb.. along with wordy weather ramble below

1. less of a milder and drier interlude possibility in south with what I previously mentioned.

2. Winds tending to be more variable than first thought.

3. Slower transition to brief westerlies than thought may be the case in previous post.

Beyond..

Outlook for very early days of March mostly hasn’t changed though in terms of the weather conditions the UK and northwestern Europe will probably experience, (relatively cold and wet at times with snow on hills over northern UK possible) but synoptically a lot may have for 1st-3rd march,  a sluggish moving series of low pressure systems surrounding northwest Europe and UK looks to be the genuine consensus atm with wind direction potentially very variable for a time with an easterly component but switching west/northwest regardless a few days into March with heights to our west and northwest likely more prevalent than average keeping lows on a more southerly track compared to average, this last part similar to last outlook post.

My previous post stating along the lines of a more likely than not transition to drier and much milder weather for southern and southeastern areas temporarily towards end of first week of March curtesy of southerly tracking lows stagnating over mid Atlantic with heights building to south and southeast, still could take place, I don’t think the scenario likelihood has dropped enough for me to not be as confident of this as a possibility but the additional possibility is also there for the slow moving areas of high and low pressure systems that are expected, to possibly align themselves in a way that keeps not only less mild conditions over the UK throughout the whole of early March and very unsettled conditions in western and northern areas, but possibly very wet in the south too, with exceptionally wet weather over parts of northwest Europe a possibility, with the tendency for weather fronts to get stuck over northwest/west Europe interspersed with heavy showers in intermittent northwest airstreams.
 

Either scenario seems plausible atm, whether the wettest conditions would efffect UK or areas to our south remains to be seen but a lengthy dry high pressure dominated period showing no sign of returning before mid March, if this changes you can be sure I’ll mention it, although there will be drier interludes obviously and in early March the direct sunlight without wind can have a fairly warm feel to it, so hopefully some decent sunny spells either side of rain bearing fronts, showers, wintry showers (north).
 

Will update again in a week or two with a recap of how outlook went.

Take care.

[ANYWEATHER]

24 minutes ago, Jordan S said:

a big adjustment to Sundays low pressure system at short timeframe this morning with the orientation and location over the North Atlantic,  

Well not according to the ecm 00z and gfs 00z. But this feature is likely to go south rather than north, but depends how it deepens ,if it deepens more will go north ,less so and it stays south. ....

[Rain All Night]

15 hours ago, Rain All Night said:

12z deterministic runs, Wed 21st to Tue 27th (day 7)

Divergence after 96 hours (Sat 24th), though the difference between the outcomes on offer is not likely to be of great interest to many here since there are no deep cold air masses in the mix.

12z ensemble means, Wed 21st to Wed 6th (day 15)

Looking back at my posts over the past week or so, I think our three 15-day ensembles have, as a team, given us good guidance on the progression through our upcoming battering:

21st Feb - round 1

25th Feb - round 1.5 (with GEFS making much more of the trough going into Europe after this point)

29th Feb - round 2

What happens beyond that (day 10+, the first days of March) remains unclear for now - as illustrated by the rather different directions each of the three ensemble means take after this point - but personally I'm not going to count on it being anything settled.

0z deterministic runs, Wed 21st to Wed 28th (day 7)

GFS has this morning 'capitulated' to the ECM's depiction of the toppling Atlantic ridge - but of course, nobody is paying much attention to that, since none of the suggested outcomes on either side have been especially interesting for the UK.

0z ensemble means, Wed 21st to Thu 7th (day 15)

As with the op runs, the shift of the GFS ensemble towards the other two models is noticeable this morning. They're all now showing similar progressions into the first week of March.

We have a new signal emerging in that first week of March, which is for a build of heights to our east. It's too early for me to guess at the possible impact of this at present. The GFS ensemble allows this signal to fade away into deep FI, but the ECM and GEM hold it in place.

Edited February 21 by Rain All Night

[Dennis]

so how long we waited for such a chart but next week we have a nice chance, NE winds

Edited February 21 by Dennis

[Joseph Hudson]

so what will a  ssw  in early march   potentially cause a cold spell or a mild spell.

[raz.org.rain]

 Joseph Hudson undetermined so far, it could go either way. I believe there's still a few milder outputs turning up in the ensembles.

[TwisterGirl81]

 raz.org.rain  That ECM  hopefully it’s milder option, I don’t want a cold spring like last year and especially after this dull wet autumn/winter.

We need a warm dry sunny spring to be honest 

Edited February 21 by TwisterGirl81

[keithlucky]

 Joseph Hudson Big reversal coming,winter has a sting in it's tale.Expect rapid cooling as wind swing to easterly.

 

 

Edited February 21 by keithlucky

[feb1991blizzard]

GFS 12z FI is a stonker, a penetrating N'ly wind and snow showers East coast with a widespread severe frost well inland.

[feb1991blizzard]

plus look at this for a reversal.

big reversal filtering down

[RJBingham]

As requested, FI cold spell, GONE.

[daz_4]

Not sure if it sad or hilarious to post wintry charts 380 hours away on 21st February. 

Meanwhile not even a night frost on GEFS.

[Anthony Burden]

Evening all.GFS deep into fantasy island possibly picking up this major SSW with northern blocking showing its hand.A definite chance that March could have a below CET and turn out a cold over all month.
 

 

[Jordan S]

 ANYWEATHER

Given that the Ecmwf has kept to its southerly track keeping rain away from southern England and Wales on Sunday in today’s afternoon output, I would not want to disagree with what you are saying. It’s a little more uncertain the track now that’s for sure. Should all come to one final solution by tomorrow morning and we’ll see what it shows.

[Cheshire Freeze]

 feb1991blizzard quite.

Would not be surprised if this spring follows the typical Nino pattern with winds mostly north of west into March and perhaps April.

I wouldn’t be counting on a warm early-mid spring by any stretch.

[feb1991blizzard]

 Cheshire Freeze

Question is can we get something potent enough to deliver? like this.

check out some of the March / April charts from the 50s, most of them better than the Jan / Feb combos from the 1ties and 20's of this century.

Edited February 21 by feb1991blizzard