Valid: Mon 07 Oct 2013 06:00 to Tue 08 Oct 2013 06:00 UTC
Issued: Sun 06 Oct 2013 21:10
A level 1 was issued for Algeria and Tunisia mainly for large hail, severe wind gusts and excessive precipitation.
A level 1 was issued for SE Italy coastline and western coastline of Balkans mainly for excessive precipitation.
A low-amplitude flow pattern will prevail over the northern half of Europe with strong westerly flow in the mid to upper troposphere. On the other hand, quasi-stationary cut-off low centered over Sardegna and Corsica will barely move, creating "stagnant" synoptic pattern over the southern part of Europe. Lack of sufficent low level moisture and steep mid-level lapse rates will preclude any DMC over most of Europe, the only exception being an area influenced by the cut-off low. Here, combination of cold mid-level temperatures and warm / moist boundary layer influenced by the Mediterranean Sea creates environment ripe for thunderstorm development.
... Algeria, Tunisia through southeastern Italy coastline towards Balkans ...
12 UTC Tuesday soundings from the area confirm presence of quite moist conditions up to 600 hPa along with moderate CAPE and moderate degree of vertical wind shear. Situation will change only slightly for the following day with the major tongue of latent instability developing over the Ionian and southern half of the Adriatic Sea. Steeper mid-level lapse rates, along with stronger vertical wind shear will enhance the large hail and downburst threat with developing storms over N Africa. Towards the northeast, the most prominent threat will be in the form of excessive precipitation, especially in case that training pattern evolves with multicellular storms oriented perpendicularly to the coastline. Due to the lack of strong synoptic scale forcing and absence of prominent low-level jet, Level 1 seems to be sufficient for this situation.