Storm Forecast
Valid: Wed 06 May 2020 06:00 to Thu 07 May 2020 06:00 UTC
Issued: Wed 06 May 2020 07:04
Forecaster: PUCIK
A level 2 was issued across W Iraq and Iran mainly for damaging wind gusts, heavy precipitation and large hail.
A level 1 was issued across W Iraq and E Turkey mainly for heavy precipitation, severe wind gusts and to the lesser degree for large hail.
A level 1 was issued across Russia mainly for heavy precipitation and large hail.
A level 1 was issued across parts of NW and W Italy mainly for large hail.
SYNOPSIS
Two main macrosynoptic features during the forecast period will be a deep cyclonic vortex centered over Ukraine, shifting to the SE and an amplifying ridge that will stretch from W Iberia towards the UK. In between of these features, a strong northerly to northwesterly flow has developed at mid to upper troposphere. Further SE, a trough will rapidly travel E across the Middle-East during the day. At the same time, another short-wave, linked to the deep cyclonic vortex over Ukraine, will cross Italy and parts of Balkans, moving S and affecting belt from Central Italy to the Aegean and W Black Sea by Thursday morning.
Closer to the surface, a cold front has stalled across France and NW Italy, while it will continue with S and SE movement across the Aegean Sea and Balkans. Across Russia, a large warm sector will develop in between of S to N oriented cold front and W to E oriented warm front with modest lower tropospheric moisture.
DISCUSSION
... Middle East, E Turkey ...
Thunderstorms are already ongoing over the forecast area on Wednesday morning. Satellite imagery reveals short-wave trough rapidly moving eastward and a dry intrusion region devoid of convection spreading eastwards over Iraq. Forecast soundings show skinny MLCAPE reaching around 500 J/kg with the lack of steep mid-troposheric lapse rates. At the same time, very long and straight hodographs are simulated over the area, with mean flow around 700 hPa reaching 25 - 35 m/s. Primary threat will be damaging wind gusts, even though as of now there are no hints of forward propagating MCS over the area, perhaps due to the lack of deep cold pools due to the moist atmosphere near the ground. Large hail and excessive rainfall may occur as well. The highest severe weather threat will exist between 06 and 09 UTC, quickly diminishing afterwards, even though numerous rounds of storms will be possible also in the afternoon. These storms will be weaker given DLS of only around 10 - 15 m/s.
... Russia ...
Widespread CI is forecast along the cold and warm fronts and scattered CI in the warm sector in between, owing to the uncapped parcels and rather low LFC. DLS in between of 10 to 15 m/s will favour multicells, stronger of which may cause heavy rainfall or large hail. Large hail threat will be limited by skinny CAPE profiles.
... Italy ...
As the short-wave trough crosses the region, together with a cold front, isolated CI is forecast across parts the country. The uncertainty is quite high given large spread in the numerical models as some of them show no initiation at all. While CAPE should stay rather marginal, strong DLS is forecast both over NW and W Italy, with DLS exceeding 20 m/s. Straight hodograph is suggestive of possibility of splitting supercells that may locally produce large hail. Have issued small Lvl 1 for the areas which have the highest chance of experiencing CI in strongly sheared environment.
... Algeria, Tunis ...
All of the NWP suggests overlap of moderate CAPE and strong DLS over 20 m/s over the area in the afternoon to evening hours. At the same time, models also simulate high values of CIN and LFC above 700 hPa so that initiation is very unlikely. With the lack of clear forcing factor both from meso and synoptic scale perspective, NWP forecast of no convective precipitation over the area seems reasonable and no lightning or severe lines are introduced.
