Convective Outlook: Mon 18 Jun 2018
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Mon 18 Jun 2018 - 05:59 UTC Tue 19 Jun 2018

ISSUED 20:20 UTC Sun 17 Jun 2018

ISSUED BY: Chris/Dan

The passage of a shortwave trough on Monday evening will result in a narrow temporal window of cool air aloft overlapping relatively warm SSTs and steepening mid-level lapse rates, within a highly-sheared environment. Scattered squally showers are likely to develop over Lewis during the second half of the afternoon, the focus then shifting over far NW mainland Scotland to Orkney and Shetland by evening.


Instability is rather low, but the strong shear may be enough to compensate to produce some isolated / sporadic lightning, primarily between 15z - 21z. Some strong gusts of wind may be possible near some of these showers. Beyond 21z, increasing subsidence aloft, weakening instability and a reduction in shear will result in shallower, disorganised convection and hence a very low risk of lightning.