Saturdays SystemAdded : Friday at 14:05 Some potentially disruptive snow across East and Southeastern areas on Saturday as a frontal system runs in from the West during Saturday morning and into Saturday afternoon, but the setup is slightly different to yesterday, but with a similar flavour...
Take a look at the forecast chart for tomorrow around midday :-
You can see low pressure coming in from the West and you can clearly see the trough which brings the rain/snow across England tomorrow. The scenario is similar to yesterday, we have a trough, we have colder air to the East, but what's different is no low pressure system running along the actual trough.
So, what causes the snow? After all, most times you will see the frontal precipitation fall as snow initially and then turn to rain as the surface warm front comes through, this is what happens across Western areas overnight and into tomorrow morning.
But, across the East and Southeast it's a little different. If you look at the trough then you can see the further away from the centre of the low the more pronounced the trough. We call this "sharpening" and it means the front or trough remains not only active, but winds behind and ahead of the front converge with Southeast winds ahead and Northwest winds behind.
This convergence means the trough is likely not only to be active, but also pull in colder air ahead of the front for Eastern areas.
The GFS ► picks up on this well :-
If the models are right and the trough sharpens like this then 5-10cm of snow is possible across Southeast and Eastern areas as the front slows, intensifies and precipitation falls through the colder surface air. If, the front doesn't sharpen as much, then the milder air will move through a little quicker from the West.
Who would be a meteorologist eh? Worth bearing in mind though for Eastern viewers as the potential for disruptive snow tomorrow later morning is certainly there.
METEOROLOGIST : MARSH |