Convective Outlook: Wed 19 Dec 2018
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Wed 19 Dec 2018 - 05:59 UTC Thu 20 Dec 2018

ISSUED 21:22 UTC Tue 18 Dec 2018

ISSUED BY: Dan

Upper low remains centred to the northwest of the British Isles on Wednesday, but with a series of troughs rotating eastwards around its southern periphery helping to create windows of deeper instability (and hence periods of increased convective activity). The broad theme sees cold mid-levels atop relatively warm SSTs, generating a few hundred J/kg CAPE. Numerous showers are expected to develop over open seas, then transferring inland by steering winds and sometimes well-inland as organised trough features move through in the westerly flow.


While a few lightning strikes and small hail will be possible from the most intense cells almost anywhere, there appears to be some consensus for a slightly increased risk over the English Channel, particularly during Wednesday evening and night as another surge of cold mid-levels / falling heights overspreads the area, combined with low-level convergence. Main concerns are lack of notable shear and rather saturated looking profiles, which would suggest lightning activity may be quite sparse - and so, rather hesitantly, issued a low-end SLGT.