Thunderstorm forecast #Europe, #NorthAmerica and #Asia (Prognoza furtuna pentru astazi in Europa, America de Nord si Asia).
Storm forecast #Europe, #NorthAmerica and #Asia. Thunderstorm forecast.
Thunderstorm forecast Europe
Valid: Fri 09 Sep 2016 06:00 to Sat 10 Sep 2016 06:00 UTC
Issued: Thu 08 Sep 2016 20:28
A level 1 was issued for Catalonia mainly for large hail and excessive rain.
SYNOPSIS and DISCUSSION
Wavy trough-ridge-trough pattern affects N-Europe with no substantial shift to the east. Further south, a pronounced closed upper low still resides over the CNTRL Mediterranean and again reveals no significant forward motion. This stable pattern (motion-wise) results in scattered thunderstorms mainly over and next to the Mediterranean. The main bulk of activity occurs beneath the large-scale upper low, which includes an area from the Alps to Greece. Weak DLS and sub-1 kJ/kg MLCAPE support scattered multicells with locally heavy rain and gusty winds, next to graupel. A localized stronger but still sub-severe storm may erupt over the NE Aegean Sea and next to the Sea of Marmara, where DLS increases to 15 m/s. An isolated large hail event is possible.
Presence of rich maritime BL moisture and a northward crawling EML create 1-1.5 J/kg MLCAPE over Catalonia during the afternoon hours. CI occurs either diurnal driven over mountains or in response to the passage of a weak short wave, which rounds the base of the deep NE Atlantic trough. DLS of less than 10 m/s supports disorganized convection. Still, magnitude of CAPE my support a few intense updrafts with large hail and heavy rain and a level 1 was issued. Thunderstorms gradually weaken until midnight.
Else, isolated thunderstorms develop over a broad area. During the night, the main activity starts to shift offshore within the highlighted areas. This activity remains sub-severe.
We will keep an eye on the cold front passage over NW-Europe, linked to a rapidly NE-ward swinging mid-level trough. There will be a short time-frame around 18-21 UTC (according to GFS), where a dry slot and the eastbound moving cold front overlap. However, strongest lift will already be displaced to the east with strong subsidence indicated. Nevertheless, models agree in weak CAPE build-up along / just behind that front and a temporarily better structured convective line can’t be ruled out N of Ireland and over Scotland. The main threat would be strong wind gusts. Whether a low-end tornado risk evolves cannot yet be answered due to ongoing differences of aforementioned features in various models. Overall uncertainties preclude the issuance of any lightning area for now.
Lightnings past 24 h
Credit: weatheronline.com, estofex.com, wetteronline.de