Convective Outlook: Sat 11 Jun 2016
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Sat 11 Jun 2016 - 05:59 UTC Sun 12 Jun 2016

ISSUED 10:20 UTC Sat 11 Jun 2016

ISSUED BY: Dan

UPDATE 10:20 UTC Minor adjustments made to expand SLGT across England

Shortwave trough will slowly migrate NE-wards across the British Isles on Saturday. At the surface, a warm, moist airmass will be present, characterised by dewpoints in the low-to-mid teens Celsius, which when heated by strong insolation will yield some 200-300 Jkg-1 MLCAPE. Scattered showers and a few thunderstorms are likely to develop along areas of wind-convergence, persisting into the evening hours before weakening in intensity overnight.

Question marks surround how extensive cloud cover may be, and its ultimate affect on quality of insolation which may inhibit convection in some areas. For now we issue a broad low-end SLGT, but it is possible this may need to be shrunk locally. Main threats will be from local flash flooding given slow-moving heavy downpours.

Falling heights over/behind the approaching Atlantic occlusion and strengthening DLS may also allow a cluster/line of convection to develop on Saturday night, sliding across S Ireland and extended towards Pembrokeshire/SW England towards 6z Sunday. Have extended the LOW threat area to cover this risk, but there may be potential to upgrade to SLGT if lightning activity proves to be significant - too much uncertainty for now.