GFS temps...

[mushymanrob]

If you remember, last Summer the GFS excelled itself in predicting the exact temps, the exact dates and the exact areas 40c was to be reached... in fact its whole heatwave temperature predictions were pretty consistent and turned out accurate for several days.... we were impressed..

So why are they now so terrible?... its already 27c at 10.00am where the GFS predicted 23c max ! The GFS didnt get close to the 3 x 30c's we have had, and 30c is possibly today... which is significant because itll close the 30c Anomaly (June 13th being the only day in Summer when 30c hasnt been reached).

[sunny_vale]

Do the models take into consideration any background warming associated with CC, which might add a degree or 2 to temperatures on the day vs synoptical predictions? (Might be a stupid question but always wondered). For me that's why I see we get the 'undercooking' of temperatures at times so to speak. Also, I suppose that wouldn't explain the accuracy of last year either.

[Scorcher]

1 hour ago, mushymanrob said:

If you remember, last Summer the GFS excelled itself in predicting the exact temps, the exact dates and the exact areas 40c was to be reached... in fact its whole heatwave temperature predictions were pretty consistent and turned out accurate for several days.... we were impressed..

So why are they now so terrible?... its already 27c at 10.00am where the GFS predicted 23c max ! The GFS didnt get close to the 3 x 30c's we have had, and 30c is possibly today... which is significant because itll close the 30c Anomaly (June 13th being the only day in Summer when 30c hasnt been reached).

Agree that the GFS has been too low, but so have most of the other models in this spell. 

I wonder if the dry soil is having something to do with it. The Met Office have been consistently too low as well with their predictions (they are generally always pretty conservative with the local forecasts on the website).

[mb018538]

Think they are all bad at it. Just seen Darren Bett saying today will see 27-28c maxima....when we've already reached 28c in multiple locations by midday. It's clearly a 29/30c day, so why not show it?

I know MeteoGroup worship the ECM, but if you go off that for today it shows 26c as the max here - we've already reached 28c by midday. So it's just wrong.

[The PIT]

GFS has been way off generally since winter. Only this year I've had to add 3 to 4 degrees to the predicted high. The Beeb weather presenter did say the models were undoing the temperatures as well. So whether the model has been tweaked in the last six months I don't know. I also noticed it tends to over do rainfall as well now so it's got big problems.

[Scorcher]

55 minutes ago, mb018538 said:

Think they are all bad at it. Just seen Darren Bett saying today will see 27-28c maxima....when we've already reached 28c in multiple locations by midday. It's clearly a 29/30c day, so why not show it?

I know MeteoGroup worship the ECM, but if you go off that for today it shows 26c as the max here - we've already reached 28c by midday. So it's just wrong.

Totally agree with your point about these forecasts.

It's a MAXIMUM temperature at the end of the day so if anything they should be too high- definitely not too low other than the odd occasion.

In the US the forecasters seem to get the concept of a max temp or 'high' as they call it much better than ours do.