Convective Outlook: Tue 28 Mar 2017
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Tue 28 Mar 2017 - 05:59 UTC Wed 29 Mar 2017

ISSUED 18:09 UTC Mon 27 Mar 2017

ISSUED BY: Dan

A shortwave trough will migrate NE from Biscay and across the British Isles on Tuesday, accompanied by cool mid-levels and hence steeper lapse rates. Assuming this phases favourably with diurnal heating, several hundred Jkg-1 CAPE will allow scattered showers and a few thunderstorms to develop. However, there is a chance that the upper trough may move through slightly too early for peak heating. 

Nonetheless, a SLGT has been introduced where there is some reasonable confidence for an overlap of instability and upper-level support for at least a few scattered thunderstorms to develop, especially during the afternoon/early evening. It is plausible another SLGT may be needed for portions of E Wales and the Midlands into southern parts of N England, but forecast profiles look drier farther east with hints of capping - so while a few showers and/or thunderstorms are also possible here, they are likely to be more isolated / well-scattered in nature, and hence coverage perhaps not high enough to upgrade to SLGT at this stage. 

Given instability and dry air aloft, hail up to 1.5cm in diameter is possible in the strongest cells.