Forecasting The HotSpotAdded : Monday at 10:05 Numerical Weather Models are good... Especially when it comes to forecasting maxima temperatures across countries like the UK. If you take a look at the maximum temperature being forecast today from Arome you can see this :-
It should come as no surprise that the model indicates London as seeing the hottest temperature with 32c progged, but if you take a closer look at the chart you can see 31c across much of Central Kent, in particular between High Weald and the North Downs (Tonbridge and the Medway areas).
The reason for this is that a light Southerly wind will descend over the top of High Weald which raises the temperature slightly to the North of it (called a weak Fohn effect or katabatic warming).
The other thing which numerical weather models have is a high resolution soil type template. The model will know what type of soil will absorb, retain or lose heat and at what speed.
Some of the lower resolution models struggle with this feature. A good example is comparing the above image to a lower resolution model such as ICON :-
Obviously, for the forecasts here on Metcheck we take a blend of many of these models and compare them to actual observations before forecasts are issued. But if you find your maximum temperature always a degree or two warmer or colder than we forecast then it's likely to be down to very local effects such as soil type or nearby higher ground.
Incidentally, this is the maximum forecast for tomorrow :-
You can see how the heat transfers West as cooler Northeasterly winds come into Eastern areas. Again, the Fohn effect develops with the warmest temperatures across West London and to the lee of the high ground across Western areas such as Exmoor and West of the Mendips.
METEOROLOGIST : MARSH |