Convective Outlook: Tue 28 Jun 2022
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Tue 28 Jun 2022 - 05:59 UTC Wed 29 Jun 2022

ISSUED 06:07 UTC Tue 28 Jun 2022


Longwave upper trough will drift slowly eastwards across Ireland and western Britain on Tuesday, while a shortwave lifts northeastwards during Tuesday daytime. Strong mid/upper tropospheric flow will create a strongly-sheared environment, and as such there may be broken line segments on the rear side of the frontal rain that crosses Ireland during the morning hours. Forecast profiles appear to be very moist with weak instability, suggesting the lightning risk is rather low - but a brief spell of heavy rain/gusty winds will be possible. The front should clear reasonably quickly to allow sufficient heating of the residual moist airmass (dewpoints 11-14C) over Ireland, yielding 200-500 J/kg MLCAPE across central/northern areas. Bands of heavy showers will likely develop and migrate northeastwards during the afternoon and evening hours. Given modest instability and 30-50kts 0-6km shear, a few thunderstorms seem plausible - perhaps especially close to the north coast and then points offshore towards W Scotland. A couple of fairly active storms, with tops perhaps exceeding 21,000ft, may be possible given the magnitude of shear compensating for limited CAPE.

Winds appear fairly unidirectional throughout the profile, suggesting the potential for linear features that may train over similar areas, and also tending to limit the tornado risk - however, locally backed surface winds near the Ulster coast may provide an opportunity for some low-level rotation as convection approaches and moves offshore. The strongest cells may produce local gusts of 40-50mph and hail up to 1cm in diameter; the fast storm motion should limit the risk of surface water flooding - and so all in all this is deemed below SVR criteria (that said, where cells train over similar areas then this could produce some locally high rainfall totals).