Storm Forecast
Valid: Tue 08 Sep 2009 06:00 to Wed 09 Sep 2009 06:00 UTC
Issued: Mon 07 Sep 2009 22:06
Forecaster: VAN DER VELDE
A level 1 was issued for parts of Finland and N Russia mainly for severe convective gusts.
A level 1 was issued for NW Turkey and eastern parts of Greece and Bulgaria mainly for excessive precipitation, and waterspouts at the Black Sea.
SYNOPSIS
A deep depression north of Scotland develops a core pressure under 970 hPa (GFS) while tracking northeast with a significant wind field. Its associated cold front may have slightly unstable stratification but EL heights suggest convection could reach only to very low levels, limiting any tornado potential imposed by strong deep layer, SREH and low level shear, and a strong PV anomaly. However, a forced rainband may develop with severe gusts for Scotland and W Norway.
The other active synoptic system on the map in an upper cut-off low over western Turkey, with ample instability to work with.
A smaller disturbance will move over northern Scandinavia into northern Russia.
DISCUSSION
...NW Turkey and eastern parts of Greece and Bulgaria...
Persistent advection and deep convergence of moist air onshore from the Black Sea with predicted large instability, low LCL (<1000m) and slow storm motion vectors appear favorable to an episode of locally to perhaps regionally excessive convective rainfall. SREH and deep layer shear are moderate and may enhance storm organization. Low level shear is large over Bulgaria and Romania but does not have an overlap with the instability. Relatively strong low-level (0-3 km) CAPE should be favorable to waterspouts especially if low level winds weaken.
...parts of Finland and N Russia...
A shortwave trough passes in the early morning over north/central Finland, and during afternoon over Arhangelsk Oblast. Instability signals are weak but consistent in GFS. LCL heights are low while DLS near the jet of > 25 m/s, SREH 150-200 mē/sē , and LLS >12 m/s could be sufficient for organizing a line producing severe gusts, or perhaps a tornado.
