Storm Forecast
Valid: Mon 08 May 2006 06:00 to Tue 09 May 2006 06:00 UTC
Issued: Sun 07 May 2006 19:12
Forecaster: GROENEMEIJER

(thunder line amended Su 7 May 21:01 UTC)

SYNOPSIS

Monday at 06:00 UTC...
A high pressure area is situated over western Scandinavia. A strong westerly jet is moving eastward over southern France/northern Spain and is expected to have its exit region over northern Italy on Tuesday morning.

DISCUSSION

Southeastern France, northeastern Spain...

In the wake of the residual convective cloudiness of the previous night, an area with rather favourable conditions for severe convective storms is expected to develop.

Some clearing is expected as drier mid- and upper-level air is advected over the region, which will allow for strong insolation. As a result, MLCAPE around 500 J/kg is expected to form.

Increasing vorticity advection with height suggest rising motion will occur and lapse rates will steepen.

Consequently, it is expected that convective storms will redevelop during the late morning and early afternoon.

Deep-layer shear is expected to be strong, with values around 20 m/s (bulk shear in the 0-6 km layer) in most places, and around 30 m/s over the southern part of the level 1 area.

This suggests that the storms may develop rotating updrafts and will have an enhanced potential to produce large hail. The storms are likely to develop fairly rapidly into bowing systems that move east or northeastward across the level 1 area.

Locally, they should be capable of producing severe gusts, but the absence of a well-defined deep, dry layer of air, or particularly strong winds at the top of the boundary layer, will likely prevent a more widespread windstorm event.

The threat of tornadoes should be relatively small because of the only moderate low-level shear.