Storm Forecast
Valid: Sun 18 Oct 2015 06:00 to Mon 19 Oct 2015 06:00 UTC
Issued: Sun 18 Oct 2015 00:04
Forecaster: TASZAREK

A level 1 was issued for S Portugal mainly for excessive precipitation and in lesser extent for severe wind gusts and tornadoes.

SYNOPSIS

Weather in the most of the central, northern and eastern Europe is influenced by high over British Isles and large cold drop centered over Germany. Such a setup drives to these areas polar marine air masses that in this time of the year are unlikely for the thunderstorm occurrence and bring rather cloud and foggy weather. In the southern Europe an unstable warm and moist air mass occurs but is capped and CI do not take place. In southeastern Europe a trough with moist and unstable air mass on its eastern and southern flank is expected to reach south Portugal during the end of the forecast period.

DISCUSSION

...S Portugal...

Although there is strong signal for CI in the NWP models on the southern and eastern side of the trough, only a marginal portion of CAPE (100-200 J/kg) overlaps with DLS up to 15-20 m/s in the afternoon hours. Higher CAPE u to 1000 J/kg on 15 m/s DLS are expected during the nighttime hours where 0-1km SRH with 10 m/s LLS will be also available. Given very small area on the southern edge of the Portuguese coast where these ingredients will overlap and uncertainty related to the presence of sufficient instability during the nighttime hours, the threat for severe convective weather seems to be insignificant. Nevertheless, an isolated severe wind gust or tornado event cannot be ruled out within these ingredients. A level 1 is mainly issued for the risk of excessive precipitation due to warm and moist low level southern inflow beneath the SW mid-level flow, PW values exceeding 30mm and persistent forcing mechanism. Given DLS exceeding 15 m/s a multicell storms are plausible.