|Convective Outlook: Wed 24 Jun 2020|
|What do these risk levels mean?|
VALID 06:00 UTC Wed 24 Jun 2020 - 05:59 UTC Thu 25 Jun 2020
ISSUED 07:04 UTC Wed 24 Jun 2020br> br>
ISSUED BY: Dan
Upper ridge extends across western Europe into southern Scandinavia on Wednesday, with a longwave upper trough to the west of Ireland. The net result is a southwesterly flow aloft above Britain and Ireland, with an increasingly hot airmass (1000-850mb thickness increasing from ~1390m on Tuesday to ~1400m by Wednesday). Diurnal heating will yield 500-1,000 J/kg CAPE by the late afternoon and into the evening, but given the deep well-mixed boundary layer, substantial cap in the 750-800mb layer and lack of any significant forcing mechanism, deep convection is unlikely. This is essentially a "loaded gun" environment. Overall, the strength of the southeasterly breeze is likely to be too strong to allow any substantial low-level convergence to develop, except for perhaps N / NW England into Wales which combined with upslope flow over the mountains may just be sufficient to break through the cap and develop an isolated shower or thunderstorm during the evening over N Wales or the northern Pennines (more likely the latter) - however, even if convection manages to initiate, it may struggle to become sustained due to the very dry profile aloft.