TORRO CONVECTIVE DISCUSSION 2007/003
A TORRO CONVECTIVE DISCUSSION has been issued at 16:30GMT on
from/until: 16:30 – 12:00 GMT on
Isolated tornadoes (close to southern coasts/in the Channel Is), convective gusts to 50-60mph, occasional cloud-ground lightning, hail to 20mm diameter and heavy rain are possible in and close to the advisory area. The tornado risk is mainly overnight tonight, and largely confined to southern coastal counties. Squally winds are possible anywhere in the area.
Squally winds are also expected after the passage of the frontal system, as heavy showers/thunderstorms move through. Coastal counties are mainly at risk from this second feature.
Deep low to
the WSW of SW Eire will move slowly towards the UK. The associated upper trough
will overspread a moisture plume, with a fairly well marked triple point
expected to pass across portions of the DISCUSSION area overnight. This is
marked by a small area of instability, along with some pronounced low level
wind shear, including directional shear. This brings the highest risk of thunder/tornadoes
Following on from the cold frontal passage, the well-marked upper trough will bring squally showers/thunderstorms across the same region overnight/tomorrow morning, in an environment on strong unidirectional shear. This brings the risk of severe wind gusts and fairly large hail.
A WATCH is not deemed appropriate for this situation, given the uncertainties in convective initiation along the front. If convection develops more widely, a WATCH may be issued.