Convective Outlook: Wed 21 Jun 2023

LOW SLGT MDT HIGH SVR

What do these risk levels mean?

Convective Outlook

VALID 06:00 UTC Wed 21 Jun 2023 - 05:59 UTC Thu 22 Jun 2023

ISSUED 06:20 UTC Wed 21 Jun 2023

ISSUED BY: Dan

A shortwave trough near NE Scotland on Wednesday morning will drift northeastwards across Shetland, and eventually towards the Norwegian Sea. In its awake, weak upper ridging will develop across the British Isles with a rather broad west/southwesterly flow aloft. Embedded elevated thunderstorms may pass close to Shetland, associated with the rain/surface low that impacted parts of England/Wales on Tuesday. Elsewhere, while diurnal heating will lead to increasing instability in the lower troposphere and a scattering of showers, dry, subsiding air in the mid/upper levels will tend to suppress deep convection, and therefore lightning activity. The best environment for a few thunderstorms will be across NE Scotland close to the departing upper trough where MLCAPE of around 700 J/kg should be available, and activity here could develop fairly early in the day before waning/drifting offshore by evening. A few odd lightning strikes may be possible elsewhere, especially where low-level convergence/orographic lift aides forced ascent to punch through the dry air in the mid-levels, this perhaps most notably in SE Scotland/far NE England, and in parts of southern and eastern Ireland. As was the case on Tuesday, vorticity stretching by developing updrafts in the vicinity of CZs may encourage a couple of funnel clouds to develop.