Model Output Discussion - Spring Has Sprung

[In Absence of True Seasons]

 LetItSnow! I'm not sure what you mean? 20c days aren't uncommon in April at all, especially in the Southern areas of England. 

 

[LetItSnow!]

 In Absence of True Seasons Upper air temperatures

[Cambrian]

Hope you all had a great Easter and that the beginning of April finds you in good health.

Looking at the models over the last couple of weeks it’s easy to perceive little or no change to the pattern and no respite from low pressure for the UK and Ireland. 

However, there are slow but important changes consistently creeping in to the Northern Hemisphere profile in the longer ranges. They’ve been in recentruns of the EPS / ECM too, but here we’re looking at the 12z GEFS.

At day 5, not much change from the here and now, PV elongated in our direction, with the trough dropping down to our west, and anchored there due to an attractive bump of unseasonably warm heights along with a surface high pressure over the central Mediterranean. 

 

Another notable bump of heights up through central North America too, into Hudson Bay, maintaining the tight Bering Sea to eastern Atlantic alignment of the PV. 

By day 10, we’ve lost the heights heading up through the American Midwest into central Canada, replaced by an upper level trough, allowing the PV to fill out west, so we get low heights working down into Hudson Bay. 

 

As a result the Atlantic jet stream and trough begins to relax north, so though we still have low pressure anchored to our west, it’s further northwest and nowhere near as deep, central pressure about 20mb higher. At the same time, the loss of heights over the Mediterranean should allow easier eastern transfer of frontal systems through Northern Europe, so the setup not near as stuck. 

The same process continues through to day 16, so much indeed that the PV is now orientated Siberia to Labrador, with a fully fledged trough pointed down into eastern Canada. A good build in heights from Eastern Europe up into northern Scandinavia puts a roof over our heads so that the draught can only get in through the window.  

 

The gradual warming out of the Atlantic trough continues with the 1015mb isobar clipping the far south of the UK, high pressure relocating to the Azores, bringing the foundation for a greater chance of some more substantial ridging northeast in time, the models at least now showing signs of beginning to search out a route out of the rut towards a slow but steady improvement by, and more especially after, mid month. 

[In Absence of True Seasons]

 LetItSnow! Yeah my bad, just seen the prior replies in the thread for the context! 

[stodge]

Just a quick comment from me this evening.

Tentative signs of something more settled but not yet in the reliable so can only be noted - 12Z GFS OP ends with a return of winter (to a point) so it's far from certain if the HP evolutions put up by GEM and others will be a significant pattern change or a transient development.

[DaveF]

Another glimmer of hope from the EC46:

 

[WYorksWeather]

 DaveF CFSv2 going down similar lines as well. Trough drops out further west at week 4. But again, we've been here too often for me to take it seriously until we get closer to the timeframe.

[Alderc 2.0]

Not sure I see much in the way of settled conditions this morning, a couple of dryer days around the 6-8th of April before the Atlantic ramps right back up and piles on in with another precession of lows. GFS had mid April being especially wet and cool this morning - hopefully an outlier. 

[IDO]

 Alderc 2.0

I have been keeping an eye on the models and the mean has been the guiding star with the omnipresent underlying pattern of an Atlantic trough with the UK predominantly on the colder side of the jet, with system after system pushing west to east. So cool and wet. Looking at D8-16 mean:

Still no change in this relentless pattern so proving the point that even multiple SSWs do not mean anything for certain regions if the macro pattern is the alpha. 

[BlueHedgehog074]

As some kind of spot of comfort regarding a more settled and warmer pattern, the GEM for 2 runs in a row now ridges in an area of the Azores High over to the UK toward the day 10 period:

12Z GEM from yesterday:

00Z GEM from this morning:

Warm during the day and a chance for things to dry out a bit more. Feels like trying to grab onto straws I admit as it’s really the only model that’s being the most optimistic about it. Though nice to see it on 2 of the runs, still.

This seems to hinge on that narrow, vertical, ridge in the Northern mid to Western Atlantic (circled below) and the way Low Pressure drops to the South of the UK between that and the European ridge to the East over the nearby continent. 

 

That little Low dropping South of the UK towards Iberia allows the doorway for the Northern mid Atlantic/Azores ridge to sneak into the UK. 

Closer to the time, there’s no guarantees the ridge in the mid Atlantic/Azores area will end up being like that (if it ends up existing at all). Depending on your weather preferences, would have to hope that models such as the GFS are handling the pattern into next week incorrectly, as you can see below the GFS has the ridging to our West/South-West over the Northern Atlantic much flatter and the Lows just roll over the top of it (although it does kinda seem on its own with the flatness in that area this morning):

So can kinda understand the concerns of the post above. But would say it’s not a resolved resolution yet. I mean, personally, it would be nice to break out of the invasion of the Low Pressure systems and see some proper, drier, weather. It’s not like it can last like this forever

[northwestsnow]

After literally months of rain and slate grey skies there is hope of a change this morning.

EC mean day 9 ...

Edited April 2 by northwestsnow

[Howie]

 northwestsnow thank goodness!

[danm]

 northwestsnow ahhh I feel better just looking at that. Let's bloody hope it happens. 

[sebastiaan1973]

 raz.org.rain It is an anomaly, but with 19c in the southern part of the Benelux, I guess it is a record for this time of the year. In the summer it would mean,  30c for sure.

[ANYWEATHER]

Looking at the charts for Saturday, that plume of warmth could get temperatures in southern ,especially southeastern parts of Britain up to 21c/70 f ,if the ecm verifies , gfs not so keen as it brings the fragmented cold front in sooner ,any way one to watch ,could be a day for t,shirt and shorts albeit a very quick affair!☺let's hope the ecm is right ....! ☺ 

[Rain All Night]

On 31/03/2024 at 14:38, Rain All Night said:

0z/6z ensemble means, out to Mon 15th (day 15)

How do we get rid of the Atlantic trough?

0z deterministic runs, out to Tue 9th (day 15)

GFS, you utter troll.

0z ensemble means, out to Wed 17th (day 15)

We can be hopeful of a visit from the Azores high during the latter half of next week, but it doesn't seem it would stick around for very long. GEFS isn't interested, which is a concern.

[CoventryWeather]

The GFS continues to move towards the Euros for a drier pattern next week. 

The ECM clusters pretty good agreement on this - no GFS cluster on this mornings. The extended shows the high moving either NW or south, but plenty of uncertainty. Would have thought the drier pattern would stick for the rest of the month and perhaps the summer. 

[Rain All Night]

8 minutes ago, CoventryWeather said:

Would have thought the drier pattern would stick for the rest of the month and perhaps the summer. 

I wish I had your optimism 

[Josh Rubio]

Will it really feel that warm on Saturday though with widely 40+mph gusts and cloud? I don’t think it’ll feel a pleasant kind of warm, but more of a muggy type. 

 

Edited April 2 by Josh Rubio

[Summer8906]

 ANYWEATHER Too southwesterly, and thus too cloudy, for anything close to 21 though?

At this time of year we really need strong sunshine from an anticyclone or a "blowtorch" direct southerly or SE-ly to get temps above 20.

My guess at that synoptic would be temps around 15C by day, 13C by night and cloudy (drizzly on windward coasts) but happy to be proved wrong...

Put it this way, I am not planning any outdoor events for the rest of this week or the weekend. Will defer them until next week when there might be the chance of the odd better day if we're lucky.

 Josh Rubio Octoberish, doubtless. Or, bad September day. As I said, flatlining day and night temps around the 15C mark.

Edited April 2 by Summer8906

[Summer8906]

 CoventryWeather Recent GFS seems to transition from "deluge" to merely "cloudy to dull and thoroughly boring, with light rain at times" for next week.

Anything which doesn't bring excessive rain is to be welcomed, but I've never seen such ridiculous zonality in April before. The progged charts are absolutely typical for mid or late October. And for a 10th month running, this run of basically the same synoptics for now getting close to a year is just about unprecedented.

The 06z run does end with something anticyclonic for week 3 though, so there is a bit of hope. Spring might arrive around the 16th or 17th - which is even later than 2013 when it arrived on the 14th.

What I'd really like to see is classic April weather: anticyclones interrupted by potent N-lies or NW-lies, but I suppose that's a bit too 20th century...

Edited April 2 by Summer8906

[CoventryWeather]

 Rain All Night I'm just looking and giving insights into what models are showing. 

Not an expert but I'd suspect the high to continue to control the weather until months end - likely it will give brief NW or N winds at times. Can't see the wet weather lasting summer. 

[danm]

 

[049balt]

 danmWhat an awful presentation.  danm

[February1978]

GFS following ECM in developing high pressure around day 10, even if it is somewhat transient. Grounds for optimism?