Model output discussion 14/04/18

[Frosty.]

44 minutes ago, Ed Stone said:

Aye CS, I noticed that on the Beeb's weekly forecast: a fresher feeling 30C, come next weekend!

Looking forward to that fresher 30c Ed, these humid mid 20's are quite difficult to cope with..seriously though, what a spell this is and with a stronger high moving in from later in the week ahead, the largely fine very warm / hot conditions are here to stay for the foreseeable future.

 

 

[summer blizzard]

1 hour ago, Singularity said:

Just looking at the trade wind increase SB referred to earlier.

There are increases shown quite widely, but a notable interruption to that along the dateline which is of some note.

Also, I'm skeptical of the outlook from GEFS anyway, as it's predicting strange things for the MJO and Kelvin Wave combination at the moment. Some confusion, it would seem. Does anyone have a plot like the above but using EPS? I'm sure I've seen one out there somewhere but for some reason I don't have a link bookmarked. Thanks in advance.

 

Looking at the weekend into next week, you can really see how the high would retract to our west and stay there if it wasn't for the more Nino-like forcing coming together. Still some uncertainty over how fast it does so though, with GFS the slowest as usual. I think that slowness is behind the loss of strong ridging through the UK past day 10 on many recent runs. 

The N. Atlantic SST pattern will be playing its hand too of course. I have got the impression that the models don't resolve this very well beyond about 6 days range. So it may give us more leeway than usual for the 'poised' tropical situation at hand.

 

Now for what it's worth, here's a brief roundup of the ECM rainfall chances for the week ahead:

Monday - few light showers in SW, isolated ones eastern highlands of Scotland.

Tuesday - light showers move into much of the far south during the afternoon. I have seen other 12z model runs toying with this idea. Previously it just looked to be some high cloud.

Wednesday - scattered light showers across Cornwall, Devon, high ground in Wales, with isolated showers across Central & Southeast England. Few in NE Scotland, plenty in far-N. Scotland.

Thursday - widespread showers by the afternoon across E&W, a few on the heavy side. Some light rain or drizzle crossing much of Scotland before transitioning into heavy showers in the east.

Friday - still showers in E. Scotland, some heavy. Few elsewhere in that country. Some showers E&W but less than Thursday.

Saturday - well-scattered light showers for most. Some longer spells of light rain on high ground in the west - indicating a moisture-heavy tropical maritime airmass arriving.

Sunday-Tuesday - mostly dry apart from some persistent rain in W. Scotland on Monday.

 

So there is some scope for rainfall, but not much of it reaching usable levels. Best chance of that for E&W looks to be Thu-Fri thanks to a shallow low drifting across before being weakened to oblivion by the ridge from the Azores. Enough of a presence may remain to extend that potential through Saturday (as GFS 12z shows).

As far as temperatures go, well MWB has handily summed those up already . One extra detail - even with those showers on Tuesday, the far south still reaches the mid-20s. Also, I imagine the underestimation may be minimal during the more showery period, unless the available moisture and hence showers are being overdone, which is certainly possible given that only about 0.5% of the rain ECM had for me today has materialised (which is about 0.01% of what GFS had for me, ha!).

The interruption around the dateline is the result of two forecast typhoons.

The chart you speak of does exist but i am only aware of Mike Ventrice having it. Not in contact with him myself. 

1 hour ago, matty007 said:

Very true. I honestly think you’d be pushing 40c with a strong plume. Maybe even surpassing it. The atmosphere and ground temps are so warm now. 

Not saying it will happen, but this summer is by far the best chance we have of achieving 40c if everything drops right. 

While the temps for some time now have been very consistent and very warm, we have yet to get anything truly hot. Think that will change before long 

It's always possible that we could hit a sweet spot like the setup in 1990 (still holds the Leeds record at 34C) however the types of setups required to such length and aridity tend to proclude the extremes in that 9 times out of 10 you'll need too much of a southerly or south westerly element to waft the hot uppers and as such, the Atlantic moves in soon after (you can get warmth returning like 2003 but in 2006 and 2015 for example, it largely signalled the end). 

[ITSY]

Very rare that I post in here over the summer months, but this spell is absolutely sensational. It’s been at or above 25C by day for the last 8 days (including today), 3 over which were at or slightly over 30C. And we could have another 8+ days if the current charts are to be believed. Slightly iffy about the positioning of the low to the SW of Ireland towards the latter half of this week - get it right and you can woft in some very high temps for the weekend (widely 30-33 in S England). Get it wrong and it could disrupt the movement of HP up from the Azores for the weekend to come. Money seems to be on the first option which puts us back in the driving seat for another prolonged period of hot, settled, and sunny weather. Europe is showing us the high life before we part ways! FYI I’m 26 and this is the most prolonged spell of weather like this I can ever recall. (I recall hotter on several occasions but none have matched this for clear blue skies and duration). 

Edited July 1, 2018 by ITSY

[SizzlingHeat]

18z GFS with an almighty high pressure system across the entire UK once more. This chart for a week today is showing blue skies and temps nudging 30c in places again. Looks like the British Grand Prix is going to be a scorcher this year.

[Mike Poole]

What a chart:

Pub run at T 192, cheers, landlord!

Edited July 1, 2018 by Mike Poole

[Fourty Point Three Degrees]

Heres a snap of tonights 18z from GFS and people are complaining about southernlies…..

Edited July 1, 2018 by 38.5*C

[East_England_Stormchaser91]

18z pub run delivers another astonishing output again. The high is slightly further east, but more noticeably, it is starting to signal some ‘dangerous’ heat getting into Spain and southern France towards the latter stages before FI, which has the heat reloading yet again after what would be a significant plume event. Stupendous sums it up! As good as it gets for summer weather. 

[knocker]

The overall short range view this morning remains a continuation of the warm and dry weather for the rest of the week, interspersed with the very odd thundery shower in some places. Synoptically the low pressure remains to the south and any northward ingress is curtailed by the high pressure, centred away to the south west. reasserting north easterly ridging leading to the UK being under a very slack gradient. The same ridging forcing any Atlantic systems, spawned by the upper trough to the NW, to track north east and inhibiting eastwards movement of associated fronts.

It's been a cloudy and pretty warm night in many places as noted by the 0200 chart and 0300 WV image with thundery showers in the south and south west. We had a couple in these parts and there is a suggestion of medium level instability on the midnight sounding.

These showers will fizzle out this morning resulting in another sunny and very warm day, albeit quite humid initially, in southern and western regions but less so in the north east where cloud from an old front and onshore winds will suppress the temps. Later in the afternoon further showers may creep into the far south west.

Any showers in the south west will disappear overnight and tomorrow will be another warm and sunny day, usual caveat, perhaps not quite as warm as today.

On Wednesday the Atlantic upper trough does partly and temporarily disrupt the ridging of the high pressure and in doing so creates a a high cell to the north east and a very slack gradient in the eastern Atlantic with a cold front struggling to get past 20W. So another warm and sunny day with perhaps some isolated showers in the west and more cloud over north west Scotland with the low pressure and front reasonably adjacent.

Thursday and Friday will be very warm, particularly in the south which may well trigger some thunderstorms, but cloudier and cooler in the north as a front fizzles out against the renewed ridging.

 

[mb018538]

Great output again today.



Another big anticyclone parked over the UK by next Sunday. Temps in the south around the 30c mark again. Most places except the far north of Scotland will be warm anyway.

GEM takes the heat up a few notches as we head into days 6-10

Back over 32c/90f seems inevitable into the second week of July if you ask me.

[Sky Full]

What the four main models are showing for +144h - six days away:

 UKMO                                                           ECM

      

 GFS                                                               GEM

      

It really is unusual to have such close agreement between these four at anything beyond +72h and indicates that there is very little going on in the atmosphere to influence or disrupt the current conditions over the UK.  The conditions shown are very likely to verify and could continue for an extended period unless something happens to wake up the Atlantic and revive the jet.  As others have said, the longer this continues the greater the chances of a plume of hot air from North Africa being drawn our way and then we could see temperature records being broken.  In the meantime, I'm stocking up on ice cream.....

[mb018538]

There is still a slight ECM bias towards pulling the high back west rather than east, so if it's really extreme heat you are after, you are likely to be disappointed for now!

Also, there seems to be yet another Iberian/Biscay trough developing out by day 10:



How many times have we seen this set up already this year? Very peculiar!

[Leo97t]

GEM starts to model extreme heat building over France and starting to move up into the UK. 

[northwestsnow]

Glorious output again this morning, its looking like the 1st 10 days of July will be warm/hot for many.

Just hints longer term that a scandy trough may well form - ideally we would want to see that trough spill east but its possible we could see a pattern change on the back of this with heights building towards Greenland and a northerly of some sort.

IN the meantime plenty of warm weather to enjoy.

[Frosty.]

Superb Ecm 00z ensemble mean, high pressure / strong azores ridging and very warm / hot surface conditions continuing.

[Newberryone]

4 minutes ago, Frosty. said:

Superb Ecm 00z ensemble mean, high pressure / strong azores ridging and very warm / hot surface conditions continuing.

I’m not liking the fact the Azores high is being displaced more and more heading towards day 10 however. 

[sundog]

33 minutes ago, Newberryone said:

I’m not liking the fact the Azores high is being displaced more and more heading towards day 10 however. 

Well the good weather can only last for so long. Perhaps a sign of a summer of two halves?

[mb018538]

Could be a response to strengthening trades? A long way off at the moment though, this could change nearer the time.

[Singularity]

Trades easing again on 8th July so only a brief uptick. In theory this is too little and short lived to have much impact on our weather patterns but there's no denying that ECM has twice trended west with the ridge-trough position since yesterday's 00z. It will be interesting to see whether Nino-transition momentum is sufficient to keep the subtropical ridge more east in reality. I'd not mind a cooler few days for some recovery of stamina though, given that the Nino forcing is likely to exert a further influence by mid-month.

[Weather-history]

Week on Wednesday is a scorcher for parts on GFS 06z

 

 

Edited July 2, 2018 by Weather-history

[NO LONGER POSTING]

A long way off but that's proper proper heat.. Humidity would be off the scale 

I think it would be wise to see how this week pans out before moving forward (contradicts what I have posted) but this would be a diffrent ball game to what we have been seeing 

[Ben Sainsbury]

Now for extreme heat the GFS 6z is perfect, deepening of low towards Iberia allowing the heat to build across France to move Northwards. For a time the 22’c 850hpa isotherm skims the far SW incredible. 

[Fourty Point Three Degrees]

gfs 06z is hot next week, but next Wednesday is a long way so plenty of time for the heat to be watered down slightly.

[Guest]

I put it in another thread earlier today all the pieces are in place for a record breaking event if favorable synoptics can be delivered and hey-presto the GFS 06z obliges. 22C 850's in the south west, combined with exceptionally dry ground and peak insolation would deliver temps well into the 30's, maybe 35/36C. A slightly slower north east push of the upper trough in Biscay exposing us to those uppers for a day or two longer could threaten the all time high for the UK. Anyway still a lot of warmth and sun to get through before then. 

[mb018538]

3 minutes ago, Alderc said:

I put it in another thread earlier today all the pieces are in place for a record breaking event if favorable synoptics can be delivered and hey-presto the GFS 06z obliges. 22C 850's in the south west, combined with exceptionally dry ground and peak insolation would deliver temps well into the 30's, maybe 35/36C. A slightly slower north east push of the upper trough in Biscay exposing us to those uppers for a day or two longer could threaten the all time high for the UK. Anyway still a lot of warmth and sun to get through before then. 

Fairly big warm outlier (as expected really). Interesting that by 7 4/5 of the 20 members really kill the heat off with a sharp drop in 850 temps. Of course that still leave 15 members at or above the average - still the form horse, and the solution you'd have to favour.

[Summer Sun]

The met office have just gone public stating high pressure will be with us for another TWO WEEKS!!