Storm Forecast
Valid: Sun 06 Jan 2019 06:00 to Mon 07 Jan 2019 06:00 UTC
Issued: Sat 05 Jan 2019 12:48
Forecaster: TUSCHY

A level 1 was issued across Gulf of Iskenderun and surroundings mainly for isolated excessive rain and a low-end tornado risk.

SYNOPSIS

Ongoing blocking pattern features strong ridging just west of Europe and a deep trough over E-Europe. In-between, northerly winds advect a cold and dry air mass south, which is unfavorable for deep convection. A partial overlap of ingredients (temperate low-tropospheric moisture and steep mid-level lapse rates) exists over the W-CNTRL Mediterranean, but S-ward displaced warmed/dried off air in the 800-900 hPa layer due to foehn conditions along the S Alps keeps a strong lid over that area which suppresses convection.
Another area of interest will be the far E Mediterranean, where better LL moisture, lift and steepening mid-level lapse rates result in augmented chances for DMC activity.

Spotty short-lived and non-severe thunderstorm activity is possible over parts of S/SE Europe. These spots were highlighted by a broad low probability lightning area. Same for NW Norway but with no lightning area added due to lower confidence (e.g. if polar lows evolve and serve as foci for limited lightning activity).

DISCUSSION

...Gulf of Iskenderun and surroundings ...

During the daytime hours a strong mid-level impulse lifts NE towards the Black Sea. Attendant LL cyclogenesis moves from S-CNTRL Turkey to the NE, placing the area of interest in a broad warm sector, which diminishes from the W in course of a E-ward ploughing cold front. Main attention arises along the coasts, where a moist marine layer is still intact onshore and assists in CAPE values of 300-600 J/kg SBCAPE beneath cool mid-level air. Expected shear supports a few multicells and coastal induced enlarged LL hodographs indicate a low-end tornado risk with onshore moving thunderstorms. The main hazard will be local flash flooding due to repeatedly onshore moving thunderstorms until 12Z to 15Z, when the cold front pushes through the level 1 area. Prefrontal 20 m/s 850 hPa winds may also support a temporal training risk with augmented LL inflow. This general risk expands south to NW Syria.

Postfrontal convection affects mainly W-Syria, where an isolated orographically induced heavy rainfall threat exists.