Thursday/Friday StormsAdded : Wednesday at 16:20 A lot of head scratching for meteorologists over the next 24-36 hours as we see the combination of heat across parts of Southern and Eastern England combine with the slow moving cold front coming in from the East.
By now, you should realise that thunderstorms are created by air rising. The intensity of thunderstorms is decided on how quickly this air rises. The risk of hail comes from the temperatures in the top portion of the cloud and the risk of tornadoes comes from how much the air is rotating as it is forced to rise.
First up, Thursday :-
If you look at where the arrow is, it shows an almost triangular pattern in the isobars. You can see one isobar coming up the East coast of the UK and the other across Eastern Ireland. This triangular shape tells us that the air will be converging (or squeezed together) at lower levels. The ICON also develops a shallow surface low across England in the afternoon :-
As a result of this convergence and low pressure as well as cooler air coming in at upper levels from that cold front out West provides the risk of storms across parts of Northern and Northeast England tomorrow evening :-
Most of the mesoscale models are agreeing though that Friday provides far more energy and instability across England.
Once again, we have low level convergence :-
And we also have heat :-
The ICON model (as does the ECMWF) takes the instability a little further West across the Midlands :-
Whilst the GFS ► and the French ARPEGE and AROME show the storms across parts of the East and also another line developing across Southwest England :-
The uncertainty will be resolved when we see the upper level data tomorrow across parts of France to find out just how unstable the mid level atmosphere is. Until then it's a bit of a guessing game, but a very ripe synoptic scenario for intense thunderstorms across parts of England regardless.
METEOROLOGIST : MARSH |