Storm Forecast
Valid: Mon 16 Jun 2014 06:00 to Tue 17 Jun 2014 06:00 UTC
Issued: Sun 15 Jun 2014 21:24
Forecaster: PUCIK
A level 1 was issued for Southeastern Spain mainly for large hail and severe wind gusts.
A level 1 was issued for Eastern Algeria and Tunisia mainly for large hail and severe wind gusts.
A level 1 was issued for Italy and Western Balkans mainly for excessive precipitation, large hail and to the lesser extent for severe wind gusts.
A level 1 was issued for Bulgaria and Southern Romania mainly for excessive precipitation.
SYNOPSIS
A ridge will persist over the Atlantic, with prevailing northerly flow at its forward flank covering much of western and central Europe. In such configuration, conditions will be too hostile for DMC in these regions. Chances for DMC will increase towards the south, where low-level moisture should be more abundant. At mid-levels a positively tilted trough will stretch from Scandinavia towards Central Iberia. Speaking of surface pressure pattern, a shallow low pressure system is simulated over the central Mediterranean with a diffuse frontal boundary. A cold-front will push from Scandinavia towards Russia especially towards the end of the forecast period.
DISCUSSION
... Southeastern Spain ...
It seems that a thermal low developing during the day thanks to the intense surface heating should induce an onshore flow advecting moister airmass inland. Along with the surface heating, this should result in some CAPE development especially towards the evening hours. As axis of the trough drops southward, 500 hPa westerly wind will reach 15 - 20 m/s, opposing weak easterly low-level flow. In such configuration, moderate to strong DLS is forecast. As storms initiate in the late afternoon to evening, strong multi or supercells may develop, capable of severe wind gusts or large hail.
... Eastern Algeria, Tunisia ...
Hot airmass with steep lapse rates will remain over the area, resulting in moderate CAPE values as northerly surface flow pushes low-level moisture inland. A favourable overlap with strong DLS is expected, so that supercells could occur in this scenario. Initiation is questionable with no strong QG forcing occuring over the region. Nevertheless, diffuse frontal boundary progressing SEwards may result in some scattered cells, with stronger ones capable of large hail or severe wind gusts.
... Central to Southern Italy towards Western Balkans ...
12 UTC Sunday soundings from the area confirm that marginal to moderate latent instability is in place there, with degree of lapse rates increasing southwards. As of Monday, no major change will occur regarding instability. However, tightening geopotential gradient, associated with an approaching short-wave trough should increase the values of DLS, reaching approximately 20 m/s. Storms may be already ongoing early in the morning, thanks to the moist onshore flow. Their coverage will likely increase towards the afternoon as short-wave aproaches. In strong DLS, well-organised multi / supercells will be possible, with threats of large hail or severe wind gusts. Storm clustering along the coastal convergence zones may yield some cell training with attendant threats of excessive precipitation. While excessive precip threat should be more prominent in the north with slower cell motion, hail and wind gust threat will increase towards the south, where stronger shear and steeper lapse rates are forecast. An overnight MCS should form over the Adriatic Sea in conjuction with the passage of trough, impacting western coast of Balkans, perhaps with several excessive precipitation events. Some marginally large hail event may occur there as well.
... Bulgaria to Southern Romania ...
A moderate CAPE is forecast for the region with values around 1000 J/kg thanks to the abundant low-level moisture. Shallow low pressure system over the area will contribute to the forcing of scattered to widespread DMC. Local storm clustering may result in some excessive rainfall events, especially in the areas with rich topography.
