Model Output Discussion - Mid Summer Onwards

[Addicks Fan 1981]

8 minutes ago, WYorksWeather said:

Raw maxes from the 18z GFS for F/S/S/M/T (and yes, the heat extends from Fri-Tues for some places) are 21/25/26/24/24.

Summer for many on Sunday:

But for the cold fans, a frosty morning for many at 252 hours by Thursday 11th (not to be taken seriously!)

Think mushy wouldn't pay attention to those charts ever, the anomoly charts I post on his behalf are way more accurate.   

[mb018538]

Some pretty incredible warmth showing up again on the 00z runs for next weekend. Temps of 25/26c on the cards:



The main reason? An exceptionally warm airmass. 850s of 17c-19c in the first week of October are incredibly rare. A couple of months ago we'd have been looking at mid 30s in the same setup:

[alexisj9]

7 minutes ago, mb018538 said:

Some pretty incredible warmth showing up again on the 00z runs for next weekend. Temps of 25/26c on the cards:



The main reason? An exceptionally warm airmass. 850s of 17c-19c in the first week of October are incredibly rare. A couple of months ago we'd have been looking at mid 30s in the same setup:

Have we ever had 19⁰c  850s over us in October 

Edited October 2, 2023 by alexisj9

[I remember Atlantic 252]

8 hours ago, WYorksWeather said:

Raw maxes from the 18z GFS for F/S/S/M/T (and yes, the heat extends from Fri-Tues for some places) are 21/25/26/24/24.

Summer for many on Sunday:

But for the cold fans, a frosty morning for many at 252 hours by Thursday 11th (not to be taken seriously!)

isn't that start of low res? higher res upto 240

[Mike Poole]

850 hPa temperatures at T132:

Apart from the GFS, the other models have the +16C isotherm up to the Scottish border, and UKMO and ECM have +18C widely over England.  GFS seems to make less of the plume than the other models, as has been the case for some time.

+18C uppers in October anywhere is extraordinary, let alone over most of the country.  

Edited October 2, 2023 by Mike Poole

[MattStoke]

3 minutes ago, Mike Poole said:

850 hPa temperatures at T132:

Apart from the GFS, the other models have the +16C isotherm up to the Scottish border, and UKMO and ECM have +18C widely over England.  GFS seems to make less of the plume than the other models, as has been the case for some time.

+18C uppers in October anywhere is extraordinary, let alone over most of the country.  

GFS showing 2m temperatures up to 26'C with 850hpa about 2'C lower than other models. Suggests upper twenties are possible if the GFS is underestimating the depth of warmth.

Edited October 2, 2023 by MattStoke

[knocker]

The gfs forecast sounding for Saturday is a quite a good illustration of why surface temps, based on the 850mb temp, can be a tad tricky if the lapse rate in the boundary layer is modified by such as cloud, etc

[Paul]

1 hour ago, I remember Atlantic 252 said:

isn't that start of low res? higher res upto 240

It's the same resolution throughout these days. 

[Cambrian]

The models are playing switcheroo between days 5 and 10.

0z ECM op - heights anomalies, T850s.

 
 

 
 

Keeping all the options open. 

[RJBingham]

1 hour ago, knocker said:

The gfs forecast sounding for Saturday is a quite a good illustration of why surface temps, based on the 850mb temp, can be a tad tricky if the lapse rate in the boundary layer is modified by such as cloud, etc

About time you showed up, we're going to need some sanity soon 

[MattStoke]

2 hours ago, MattStoke said:

GFS showing 2m temperatures up to 26'C with 850hpa about 2'C lower than other models. Suggests upper twenties are possible if the GFS is underestimating the depth of warmth.

6z rolling out looks much warmer. Continues it's march towards the other models.

[Mike Poole]

7 minutes ago, MattStoke said:

6z rolling out looks much warmer. Continues it's march towards the other models.

Looks very similar to 0z to me at T126 in terms of how har north the heat gets, (0z T132 for comparison), but with cold from NW encroaching towards Scotland:

Still some way off the other models for Saturday.

[MattStoke]

5 minutes ago, Mike Poole said:

Looks very similar to 0z to me at T126 in terms of how har north the heat gets, (0z T132 for comparison), but with cold from NW encroaching towards Scotland:

Still some way off the other models for Saturday.

Hate that I can't see meteociel at work. TWO charts made it look warmer. Does though look like it prolongs the warmth into the following week.

[mb018538]

1 hour ago, knocker said:

The gfs forecast sounding for Saturday is a quite a good illustration of why surface temps, based on the 850mb temp, can be a tad tricky if the lapse rate in the boundary layer is modified by such as cloud, etc

 

Looks pretty clear to me on Saturday at least going by the GFS. The obvious limiting factor is the fact that it's October, not July, and not a straight southerly flow. 25/26c seems fair. Sunday on the GFS has more medium and high level cloud in places, but at this range purely speculation.

[MattStoke]

1 minute ago, mb018538 said:

 

Looks pretty clear to me on Saturday at least going by the GFS. The obvious limiting factor is the fact that it's October, not July, and not a straight southerly flow. 25/26c seems fair. Sunday on the GFS has more medium and high level cloud in places, but at this range purely speculation.

Monday a touch warmer.

[MattStoke]

15 minutes ago, MattStoke said:

Monday a touch warmer.

Even into Tuesday, we're still warm on this run.

Then as the last of the warmth hangs on in the far south east out to Thursday, we see a real chilly north westerly blast. Quite a flip and has been a reoccurring theme on model runs.

Edited October 2, 2023 by MattStoke

[mb018538]

11 minutes ago, MattStoke said:

Even into Tuesday, we're still warm on this run.

Wow....if it drags on for 4-5 days then it'll be right up there with warmest October spells in history for sure.

[Mcconnor8]

1 hour ago, MattStoke said:

Even into Tuesday, we're still warm on this run.

Then as the last of the warmth hangs on in the far south east out to Thursday, we see a real chilly north westerly blast. Quite a flip and has been a reoccurring theme on model runs.

It has very good support from the ensembles too, which have increased the duration a lot from previous runs, will have to see if the rest of the 12z models follow it.

[Djdazzle]

Models now firming up on a notable warm / hot spell for next weekend. October 8th date record looks under threat.

[Ajsnowy]

Gfs from next Tuesday onwards looks great for a return to wet and windy weather.

Pathetic attempt of a heatwave trying to hold on for that week.

[mb018538]

Just now, Ajsnowy said:

Gfs from next Tuesday onwards looks great for a return to wet and windy weather.

Pathetic attempt of a heatwave trying to hold on for that week.

Pathetic attempt? Not sure that a close to record breaking heatwave could be described as a 'pathetic attempt', even if it's something that you clearly don't want...

[Derecho]

It seems that the push of cooler air from the north is being delayed according to the latest GFS OP. Compare the 06z to the same time as yesterdays 12z early on next week...

Wouldn't surprise me if the cooler air sunk further west keeping us in the warm air.

EC and UKMO are more keen to bring some cooler air in but it isn't particularly cold. A sudden cold northerly looks unlikely.

[sundog]

15 minutes ago, Ajsnowy said:

Gfs from next Tuesday onwards looks great for a return to wet and windy weather.

Pathetic attempt of a heatwave trying to hold on for that week.

Pathetic attempt? What do you expect in October????

[Weather Enthusiast91]

Fingers crossed that the models show something more akin to autumn soon and that the unseasonable warmth doesn't drag on and on.

Roll on those cool crisp sunny days with single digit foggy nights and mornings.

Edited October 2, 2023 by Weather Enthusiast91

[Nick2373]

06Z shows the warm spell peaking on the 07th-08th of October then a decline in temps as the wind changes direction to a NNW bringing cooler temps from the 11th-13th with some showers chucked in. after that a lot of disagreement it will more than likely hover just above or close to average for this time of year enjoy the warmth this weekend because autumn is to follow.