Convective Outlook: Thu 21 Sep 2017
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Thu 21 Sep 2017 - 05:59 UTC Fri 22 Sep 2017

ISSUED 20:09 UTC Wed 20 Sep 2017

ISSUED BY: Dan

Sharp upper trough pivoting NE-wards across Ireland and W Scotland on Thursday will provide the focus for deep convection as cold mid-levels overspread relatively warm SSTs and diurnal heating inland, steepening lapse rates and generating a few hundred Jkg-1 CAPE. A low-end SLGT has been issued where there is a better overlap of these variables, with scattered showers and a few thunderstorms likely on Thursday afternoon and early evening, the focus shifting mainly to coastal areas of western Scotland by Thursday night. One inhibiting factor will be quite dry profiles in the mid/upper levels, which may result in more isolated shower distribution - but given steering flow, an individual shower should cover some distance, and therefore increase the potential in lightning coverage. Hail to 1.5cm in diameter is possible from the strongest cells. Relatively high cloud bases (given 6-11C dewpoint depressions) should limit the funnel potential somewhat.