Convective Outlook: Sun 28 Jul 2019
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Sun 28 Jul 2019 - 05:59 UTC Mon 29 Jul 2019

ISSUED 19:53 UTC Sat 27 Jul 2019

ISSUED BY: Dan

Negatively-tilted upper trough over Ireland and southwest Britain on Sunday will continue to dig southeastwards towards the Mediterranean, forming an eastward-propagating cut off upper low. A second cut-off upper low over Germany will swing northwestwards across the North Sea, arriving in the vicinity of the Northern Isles during Sunday night. Meanwhile, a quasi-stationary frontal boundary continues to provide extensive cloud and outbreaks of rain in a zone from Northern Ireland - Midlands - East Anglia.


Through the day the frontal band is expected to become increasingly narrow, eventually fragmenting. However, any cloud breaks and surface heating, combined with low-level wind convergence and orographic forcing (given very slack flow) may allow a few scattered heavy showers to develop along and to the north of the frontal boundary - perhaps with a few isolated lightning strikes. Any showers that do develop will tend to weaken during the second half of the evening.

Across Scotland, a few elevated showers (perhaps weakly-electrified) will run westwards on Sunday morning from the North Sea, with other additional showers and perhaps one or two thunderstorms developing by the afternoon - more especially over the W / SW mainland and the Western Isles, where a low-end SLGT has been introduced.
Another round of elevated showers and thunderstorms will approach from the North Sea towards the Northern Isles on Sunday night, associated with the approaching upper low - but lightning activity probably weakening on approach.