Convective Outlook: Tue 06 Jun 2017
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Tue 06 Jun 2017 - 05:59 UTC Wed 07 Jun 2017

ISSUED 20:22 UTC Mon 05 Jun 2017

ISSUED BY: Dan

Over the past 12 hours, NWP guidance has trended towards a slower clearance of the wrap-around frontal system over eastern Britain - consequently the window for deep convection is a little narrower, and if this trend continues then it is likely some northern portions of the large LOW threat may need to be trimmed back farther south. 


Nonetheless, on the rear-side of the upper trough (-turn cut-off low), cold mid/upper levels will advect SE-wards across the LOW threat area, steepening lapse rates and generating a few hundred Jkg-1 CAPE in response to SSTs and diurnal heating inland. Provided cloud clears NE-wards to allow sufficient insolation, numerous scattered showers are forecast to develop, perhaps weakly-electrified. Better shear will be present towards the SW, perhaps enabling some better organisation but given limited instability no SLGT will be issued for now since lightning is not expected to be widespread and / or frequent enough to upgrade to >30% probs. 

On the east coast, depending on how far inland the wrap-around rain shield extends there may be scope for some frictional convergence to develop on the inner portion of this front - hence some embedded convection may develop in an environment with marginal instability. A small LOW threat has therefore been issued, although subject to positional errors and unlikely to result in much, if any, lightning.