Outlook from Tony Gilbert...
Moderate risk of Thundery Showers UK & Ireland 09Z-21Z Sun 25th April 2010
UKMO Fax chart continues to show the development of a post frontal surface trough. High over the continent funnels moist unstable air from the Azores. Temps across the UK & Ireland expected to rise quite rapidly from late morning onwards. Destabilising the atmosphere further as a deep upper trough nudges east aloft.
Thundery showers look to be on the cards from very early on to the west though the best instability will build further east later in the day. Lapse rates could become very steep indeed. Restrictions include weak vertical shear and heavy mid level moisture. Though GFS currently favours better potential instability derived by a layer of dry air across the midlands and south of this region.
North Sea SST are around a meager 7 deg C. If the wind remain light along the east coast then an onshore breeze could in fact develop by late afternoon creating numerous convergence zones. It will be within this region that the odd funnel/ waterspout report will be possible.
PS. In theory probably the best storm chase day so far this year with slow moving thundery showers. Though severe weather unlikely.
