Outlook from Torro...
TORRO CONVECTIVE DISCUSSION 2011/011
A TORRO CONVECTIVE DISCUSSION has been issued at 13:40GMT on Monday 27th June 2011
Valid from/until: 13:40GMT - 09:00GMT on Monday 27th/Tuesday 28th June 2011 for the following regions
Parts of (see map)
Much of England
Central and eastern Wales
Extreme SE Scotland
Wind gusts to 60mph; heavy rain; cloud-ground lightning; isolated tornadoes; hail to 3cm
Reasonably steep lapse rates/EML atop moist boundary layer, approaching upper trough, and local surface convergence/diurnal heating has allowed thunderstorms to form across N England. These are within a regime of 35-40 knots of 0-6km shear, and so may have time to organise before moving offshore. Instability and shear are suffificent for hail to around 3cm diameter, 60 mph winds, and perhaps a tornado, but overall coverage appears too low to warrant a watch.
Further south, an area of mid-level showers is spreading NE across parts of Wales and the Midlands, with further showers/thunderstorms to the west of NW France. The activity over the mainland may root into the boundary layer as it continue to move NE, with an attendant risk of hail/wind/tornado, but at this stage, uncertainty about development precludes a watch.
The activity west of NW France should continue towards SW England this afternoon and then spread NE this evening and overnight. Further activity is expected to develop/move in from the SW across portions of Cent S and SE England and E Anglia overnight and into tomorrow morning. Much of this should be elevated, but cloud layer shear of 20-25 knots may be enough for mid-level rotation to develop, with an attendant risk of hail, perhaps to 3cm. Again, uncertainty over development and overall severe coverage precludes the issuance of a watch at this stage.