Dear Nick

I caught your forecast this morning at 8.58 am and at one point heard you said something like "..the focus of the heat will moved westward over the next couple of days"

My reply to that is one word and it doesn't start with 'B' but 'A', 'A' for anomalies...

If you look at some recent values for daytime maxima from two stations, Heathrow airport in Berkshire and Dunkeswell airfield in East Devon.

I had no problem finding stats for Heathrow from the Met Office site, but I had to turn to a very useful site in Spain to get climate data for Dunkeswell (ToDo: Write a piece about why the Met Office can't provide us with a site like this to access detailed climate data from across the UK & the world? http://www.tutiempo.net/clima/ how hard can it be?). The upshot was that I calculated a mean max for July for both places (1991-2012), so now I had to turn to Florida State University for SYNOP data to get the max temps for 1800 UTC for each day of this month to construct my anomalies table:

06-18 Maximum 06-18 Anomaly
03772 03840 03772 03840

July 1 21.3 17.9 -2.1 -1.5
July 2 17.9 14.1 -5.5 -5.3
July 3 21.5 17.5 -1.9 -1.9
July 4 24.9 20.1 +1.5 +0.7
July 5 26.3 21.2 +2.9 +1.8
July 6 28.1 24.1 +4.7 +4.7
July 7 29.5 25.2 +6.1 +5.8
July 8 27.7 25.4 +4.3 +6.0
July 9 27.2 24.7 +3.8 +5.3
July 10 24.6 24.9 +1.2 +5.5
July 11 23.4 21.4 +0.0 +2.0
July 12 25.9 24.5 +2.5 +5.1
July 13 31.4 28.8 +8.0 +9.4
July 14 29.8 28.9 +6.4 +9.5
July 15 30.9 26.8 +7.5 +7.4
July 16 31.0 27.7 +7.6 +8.3

26.3 23.3 +2.9 +3.9

It is quite clear from this table that the focus of the heat as far as I can see has been as much in the SW as the SE, and lowly Dunkewsell has more that matched and for most part beaten the anomalies from the king of the hot spots. The main reason for this is that the SW is the last place to be affected from the stratus and haar that spread in from the North Sea. Anomalies in the SW are approaching those of the hot spell in 1976 i.e. around +10°C and more.

Anomalies are something the Met Office don't seem to think should figure in our weather forecasts. I suppose they think that phrases like 'near average', 'cold' or 'very warm' are what the public can understand. So why is it when we come to extremes is it that we get so fixated with the hottest place in the country? When I worked as an observer at Kinloss, we though it was a hot day when temperatures neared 30°C, but at Heathrow temperatures like that and higher can occur multiple times in some summers. So 'hot' is different for one place to another, and so when you see 30°C in the SW in July like we have this year that's a whopping +10°C anomaly.

There is no reason why the Met Office can't simply apply climatological averages of a site to the forecast NWP temperature to produce an anomaly. Probably one of the reasons its never done this is that it requires a blend of data types to achieve a finished product, live data, forecast NWP data and archived climate data. But I'm certain that if they did generate this anomaly data they could produce a colour filled contour map of regions that were truly "hot" or "cold" in a more realistic and scientific manner which would not only supplement but add value to their current presentations.

Bruce.