Storm Forecast
Valid: Mon 14 Oct 2019 06:00 to Tue 15 Oct 2019 06:00 UTC
Issued: Mon 14 Oct 2019 02:59
Forecaster: VAN DER VELDE

A level 2 was issued over southern France mainly for excessive rainfall, large hail and tornadoes.

A level 2 was issued over western France mainly for severe convective wind gusts and tornadoes.

A level 1 was issued across parts of France and Spain mainly for severe wind gusts, tornadoes, and excessive rainfall.

SYNOPSIS

A relatively mild southwesterly flow prevails over Europe today, with frontal waves over the English Channel and Baltic Sates region. In advance of the major Atlantic trough invading western Europe, a surge of warm humid airmass is drawn into Spain and France, soon followed by the cold front. Significant lifting is done by the DCVA of the trough starting at 06Z over Portugal, 18Z northern Spain, 00-06Z southern France. Another low produces elevated convective storms over the Middle East, later spreading westward over the eastern Mediterranean (and Cyprus).

DISCUSSION

...Spain and France...

ECMWF and GFS models predict inland Mediterranean moisture advection towards the cold front, mainly through the Ebro Valley, southern and western France. While CAPE remains mostly below 500 J/kg over land and 1000 J/kg over sea, mid level lapse rates are rather steep and the presence of a high shear environment under the SW-ly jetstream and strong lifting suggests that severe weather chances are substantial. DLS of 20-25 m/s and 0-1 km LLS of 12-17 m/s with SREH between 200 and 350 m2/s2 suggests that storms can develop (low-level) mesocyclones which can harbour tornadoes, as well as isolated marginally large hail. The background winds in the lowest 3 km reach 20 m/s over western France and could facilitate isolated severe wind gusts (>25 m/s) with help of convective (line) downdrafts.
At night, the cold front enters the Mediterranean with very strong upslope moisture lifting over the mountain ranges in southern France. Together with the narrow convergence zone along the cold front this creates persistent convective developments (MCS) that can produce excessive convective precipitation.