Storm Forecast
Valid: Thu 09 Oct 2008 06:00 to Fri 10 Oct 2008 06:00 UTC
Issued: Wed 08 Oct 2008 21:41
Forecaster: GATZEN
SYNOPSIS
High over Europe is flanked by low geopotential over western, and eastern Europe. As an intense jet streak moves eastward over northern Atlantic, west European trough cuts off and travels southward into Morocco. To the north, Atlantic ridge merges with the European high.
DISCUSSION
West Mediterranean
To the east of the developing cut-off low over Iberian Peninsula / Morocco, warm air mass continues to spread westward over west Mediterranean. Latest ascends indicate rather steep low to mid-level lapse rates above the warm sea surface over west Mediterranean Sea and quite rich low-level moisture (Palma de Mallorca). On THU, models indicate that low pressure will persist over northern Africa, yielding an easterly flow across west Mediterranean. While high surface pressure intensifies over western Europe south of the approaching strong Atlantic jet streak, pressure gradient will strengthen over the Mediterranean. Warm air advection will likely spread into Iberian Peninsula in the wake of the cut off, where strong low-level helicity is forecast in response of strongly increasing and veering vertical profiles.
Given some QG forcing as well as weak convective inhibition, expect that thunderstorms will likely go on during the period and may merge into MCSs. Although deep layer vertical wind shear will likely weaken and spread westward, chance for severe convection is expected to increase as low-level vertical wind shear strengthens. Latest GFS model expects 25 m/s 0-3 km vertical wind shear just north/west of the warm front. This seems to support rotating updrafts. Given high low-level vertical wind shear, severe wind gusts and tornadoes are forecast to be the main threat. While highest potential is forecast in the Balearic Islands region during the day due to best low-level buoyancy, potential may move westward later on reaching the Iberian Peninsula late in the period, where some tornadoes are forecast. Intense precipitation is also forecast with the stronger storms.
