Model Discussion - Spring approaches - how warm at the end of this week?

[knocker]

Outlook - Warm, very warm for a time, and relatively dry but tending towards a NW/SE split

The NH 500mb profile and surface analysis for midnight and the Chatham, Cape Cod, sounding for same time just to show the measured 190kt jet over the eastern US

There is currently still a fair bit of rain around over the north west as the waving cold front continues to move slowly south east, and this will persist through the morning but slowly fragment on it's travels as it reaches Wales and the Midlands by late afternoon. Another mild day but cloudy for most apart from the south where there will be sunny intervals.

The front will slowly clear most areas overnight but still generally cloudy with bits and bobs of rain/drizzle around, mainly in western regions. Another frost free night except perhaps for northeast Scotland where is clearer.

On Thursday we are in the pattern that has been discussed previously so will skip any repetition and suffice it to say becoming dry and warmer with perhaps some cloud and patchy drizzle in western parts early on

Overnight Thursday through Friday a similar, very warm and dry, day but the complex upper trough to the west is taking slightly closer order and some rain may effect the north west from a surface cold front.

Another very warm day on Saturday, these temps are not written in stone, but we now have twin cyclones to the west and the trailing cold front from the initial one, now near Iceland, may bring some rain to the far west late on.

As the two cyclones adjust positions overnight Saturday through Sunday the weakening cold front will finally traverse the country so cloudy with sunny intervals and maybe just a tad cooler

 

 

Edited February 20, 2019 by knocker

[knocker]

To continue with the gfs, As can be seen at T144 there is still a lot of energy exiting the eastern seaboard so essentially the 5-10 period remains a battle between this and the resilient block

With such strong forces at play the distribution of this energy plays an important role in the detail of the surface analysis (partly explains inter run variations)  and this morning, despite some variation in position, the blocking high pressure remains in control over the UK so remaining dry with temps still above average.

[IDO]

The models have, as expected, corrected their over-amping of heights to the north.

They are now back to where they were indicating pre-X-flow. 

With the developments, we have sustained UK HP for another day or so, but by D10 it is sinking SE. Those extra two days have helped build up lower heights in the Canadian vortex, so a ready supply of cyclones awaiting their journey to our sector.

By D16 the mean:    AO>>

The wedge of heights on the AsiaPac side directing the PV to the Atlantic region traversing to our north. We have seen this before this winter and it is usually transient, so maybe a week of March dedicated to some sort of zonal flow. The AO index heading south as that wedge messes around the Arctic fields.

That wedge will eventually mix out or get drawn to similar pressure sources. Maybe further height rises in the UK/Atlantic region will find an opening and the cycle will restart. 

The wedge continues to send cold to lower latitudes but sadly the UK will need a reset to get the severe cold flow to the UK. However upper air as we near D16 is closer to climate:

London>>>

As @knocker mentioned, the jet stream is currently a powerhouse. see https://www.latimes.com/science/la-sci-sn-jet-stream-flight-20190219-story.html

Watch out for the dust: https://twitter.com/MeteoGib/status/1098115396173991936

Some very mild air to come before month's end suggesting a CET of +4c above climate for Feb!!! Enjoy!

Edited February 20, 2019 by IDO

[knocker]

The ext EPS this morning has some changes upstream vis the orientation of the Alaskan ridge/Canadian vortex and thus the Polar flows  But still indicating a strong jet out of the eastern seaboard and a weakening European ridge. So nothing alarming about to pounce out of the woodshed

Edited February 20, 2019 by knocker

[mb018538]

34 minutes ago, knocker said:

The ext EPS this morning has some changes upstream vis the orientation of the Alaskan ridge/Canadian vortex and thus the Polar flows  But still indicating a strong jet out of the eastern seaboard and a weakening European ridge. So nothing alarming about to pounce out of the woodshed

Interesting anomaly charts there....



The ECM clusters last night favour a much more unsettled prognosis. I guess the smaller cluster matches up quite well, but we will see.

Edited February 20, 2019 by mb018538

[Blessed Weather]

GFS forecast 2m temp anomaly for the next 7 days suggesting the UK average will be +4.6C above climate. Taking actual temps to 20th Feb and adding the next 7 days, a forecast anomaly of +2.4C for the month.

Next 7 days  Feb actual to 20th + 7 days

Looking at the 3-day mean 500hPa height anomaly forecasts 27th Feb to 1st March from GFS and ECM there's very good agreement that NW Europe and the UK remain well and truly under the influence of high pressure.

Both GFS and ECM had the MJO entering Phase 8 around the 14th Feb. ECM then moves quickly through to Phase 1, whilst GFS meanders around 8. Adding the typical time-lag to take us into March, the composite 500hPa heights anomaly for both Phase 8 and Phase 1 in ENSO neutral conditions both suggest a much more favourable pattern for the UK would normally be expected. With little sign of that in the extended forecasts, as others have written, it looks like the Nina-like base state continues to interfere with expectations (disappointingly, not for the first time this winter).

MJO Ph 8 composite Ph 1 

 

[knocker]

11 minutes ago, mb018538 said:

Interesting anomaly charts there....



The ECM clusters last night favour a much more unsettled prognosis. I guess the smaller cluster matches up quite well, but we will see.

As I have said before I personally have a fair amount of difficulty when comparing a mean anomaly over five days with ten sets of readings from the clusters, particularly given the map projection. There are so many variations vis the strength and position of the trough and ridge I find, just my personal opinion of course, that looking for detail a bit pointless.

[Summer Sun]

ECM op and mean much closer on today's 00z run unlike yesterday when the op went off on one and was a cold outlier at the end

London

Southern Scotland

It looks mild to very mild for the foreseeable future

Edited February 20, 2019 by Summer Sun

[Nick F]

Both GFS and ECMWF seemed to have backed off warmth for Saturday, which had been earmarked for peak of warmth, high pressure over Europe appears to be extending further west, so not such a strong southerly flow away from the far west, having said that, temperatures still in the mid-teens on Friday and Saturday afternoons, which is well above the seasonal average, but the 13th Feb 1998 record of 19.7C looks less under threat.

Almost overlooked tomorrow afternoon, Netweather's SR model indicating 17-18C over north Aberdeenshire and Moray - likely from Foehn effect in the lee of Highlands/Cairngorms.

EC has 15-16C in similar area of NE Scotland, also across Vale of York

[karyo]

51 minutes ago, Blessed Weather said:

GFS forecast 2m temp anomaly for the next 7 days suggesting the UK average will be +4.6C above climate. Taking actual temps to 20th Feb and adding the next 7 days, a forecast anomaly of +2.4C for the month.

Next 7 days  Feb actual to 20th + 7 days

 

Both GFS and ECM had the MJO entering Phase 8 around the 14th Feb. ECM then moves quickly through to Phase 1, whilst GFS meanders around 8. Adding the typical time-lag to take us into March, the composite 500hPa heights anomaly for both Phase 8 and Phase 1 in ENSO neutral conditions both suggest a much more favourable pattern for the UK would normally be expected. With little sign of that in the extended forecasts, as others have written, it looks like the Nina-like base state continues to interfere with expectations (disappointingly, not for the first time this winter).

MJO Ph 8 composite Ph 1 

 

The latest enso update shows that en nino has re-established so perhaps a better chance of a cold spell in March.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

[StormyWeather28]

This Winter is set to be the Mildest ever recorded at many stations in Ireland, incredible, especially given the Background signals . I'm hoping for some colder weather before March is out just to kill some of the insects lol

Edited February 20, 2019 by StormyWeather28

[knocker]

WV image at 1000

[kold weather]

ECM has pretty much 9 days where maxes somewhere top 15c, with multiple 16-17c. This is likely 1-2c too low for local maxes so could well see a 18-19c Max at some point in the next week.

Possibly the mildest last 10 days of Feb ever coming up?

[MATTWOLVES 3]

Absolutely garbage 6z, yet again each model run pushes any colder shots further back into (fi) it's now getting to the point of know return! What a soul destroying winter, not only have the background signals been about as useful as a one legged man at a butt kicking contest, the 5-10 day charts on cold weather have been laughable. They have nailed it everytime with the mild conditions, but my god whenever a cold shot as come into view they have constantly pushed it back another several days! Perhaps it's time to join the hunt for spring and put this miserable attempt of winter to bed! Not even one sustained northerly in 3 months!!

Edited February 20, 2019 by Mattwolves

[MATTWOLVES 3]

24 minutes ago, snowfish1 said:

It's been an absolute joke hasn't it 

Yeh its dire, you know when things are looking bad, as the big hitters on here of a cold persuasion stop posting! I will carry on searching for something but as you know a cold spell at end of march, where the snow melts before it hits the ground is pretty pointless. I feel sorry for the Scottish ski resorts, must be truly terrible! And as I post this the cold bias GFSP goes cold into fi, you just couldn't make it up! 

[knocker]

The Atlantic at 1800

[Weathizard]

41 minutes ago, Mattwolves said:

Yeh its dire, you know when things are looking bad, as the big hitters on here of a cold persuasion stop posting! I will carry on searching for something but as you know a cold spell at end of march, where the snow melts before it hits the ground is pretty pointless. I feel sorry for the Scottish ski resorts, must be truly terrible! And as I post this the cold bias GFSP goes cold into fi, you just couldn't make it up! 

Unrealistic cold crossing the Atlantic there, I find it strange we were sold the fact the GFSp was going to be considerably superior to the current GFS, it’s cold bias has been dreadful all winter, it’s been on par with the CFS imo absolutely useless.

[MATTWOLVES 3]

8 minutes ago, Weathizard said:

Unrealistic cold crossing the Atlantic there, I find it strange we were sold the fact the GFSp was going to be considerably superior to the current GFS, it’s cold bias has been dreadful all winter, it’s been on par with the CFS imo absolutely useless.

Agreed Weathizard, it seems to be selling us up the river so to speak. Latest GEFS ensembles not without interest, notice some of them dipping spikes early next month! Straw clutching again I suppose! 

[Singularity]

We've seen some hints that maybe the MJO signal briefly finds its way through with less interference, but no more than that... so here we are looking at further distorted pattern responses.

The MJO always drives amplification when active, it's where that occurs that differs depending on which phase it's in and how much interference there is from other factors. This week and next, the amplification is being distorted such that the height rises focus a fair way further south and east of the usual response. This being via stronger westerly flow persisting on the N flanks of the subtropical highs, essentially 'rooting' the major height rises to the subtropics as very resilient mid-latitude blocking features. There's no dive south and undercut of the polar jet to enable some HLB to take shape.

Generally, that jet behaviour is the critical prerequisite for some at least transient HLB to occur, while a negative AO is the one for sustained HLB to take place.

So even without the AO co-operating i.e. the SSW downwelling as hoped, were it not for the Nina-like interference, we'd likely have seen variable HLB during the second half of this month, which is good for battleground scenarios.

One of the darkest sides to being aware of long-range weather prospects, is knowing what you could have had, when it's all gone awry. 

For me, the most frustrating thing about the past few months from a professional perspective has been that due to unusually poor modelling of the MJO, we've had no reliable indicators for whether the interference would continue or come to an end; all we could do is watch the observation data come in and then adjust expectations accordingly, by which time the period of interest has been within about a week's range instead of two or three.

From this comes an important point - it's not usually this bad! So that's something to look forward to I guess .

[Weathizard]

I know it’s not current model discussion but just had this pop up in my memories from exactly a year ago, quite painful viewing

[cheeky_monkey]

2 hours ago, Weathizard said:

Unrealistic cold crossing the Atlantic there, I find it strange we were sold the fact the GFSp was going to be considerably superior to the current GFS, it’s cold bias has been dreadful all winter, it’s been on par with the CFS imo absolutely useless.

GFSP nailed the cold across N.America and its duration a long way out..it was the only model to do so

[MATTWOLVES 3]

Ice cream van alert!! Icon says if you can't get the - 12 uppers, don't worry we will send you the +12 uppers! Approaching 20c.... Wow, just wow 

 

[feb1991blizzard]

Look at that cold air near the Aleutions, quite a dry airmass and severe Gales, perishingly cold, and i thought it was severe with -7c in the day and a gentle continental tug in Dec 2010 here!.

Edited February 20, 2019 by feb1991blizzard

[MATTWOLVES 3]

1 hour ago, Mattwolves said:

Ice cream van alert!! Icon says if you can't get the - 12 uppers, don't worry we will send you the +12 uppers! Approaching 20c.... Wow, just wow 

 

Gorra love it, we have gone from the icon heat alert to the gfs 12z cold alert, only in Britain my friends!!

[Mapantz]

3 minutes ago, Mattwolves said:

Gorra love it, we have gone from the icon heat alert to the gfs 12z cold alert, only in Britain my friends!!

6 days vs almost 15 days, non-comparable really.