Storm Forecast
Valid: Sat 21 Mar 2009 06:00 to Sun 22 Mar 2009 06:00 UTC
Issued: Sat 21 Mar 2009 00:07
Forecaster: DAHL

SYNOPSIS

Intense upper low will move from the central Adriatic Sea southwards, covering the S Balkans as well as the central Mediterranean by the end of the forecast period. Attendant SFC low and its associated cold front will cross Greece and the Aegean Sea on Saturday per model guidance, providing a focus for potentially severe convective weather. Another, weaker upper low resides off the Iberian west coast, maintaining a weak cyclonic circulation at low levels, supporting low level warm/moist advection, which is simulated to result in weak instability during the period. Otherwise, cold/stable conditions, obstructive to deep convection, persist over Europe.

DISCUSSION

... Greece ... Aegean region ... S Adriatic Sea ... S Italy ...Tyrrhenian Sea ...

It seems that CAPE will remain quite marginal, but DLS in the 25 to 30 m/s range should be sufficient to aid some storms in becoming organized. Dominant mode will likely be linearly-organized multicells/line segments and isolated mesocyclones. This should result in a threat for marginally severe wind gusts/hail, and possibly also a tornado or two given 10 m/s LLS over the S Aegean Sea as well as over the E Aegean coastal regions simulated by the GFS.

In the wake of the front, cellular convection is likely to develop/persist. Virtually absent capping, steep low-level lapse rates, and low LCL heights suggest that a few waterspouts may ocur. However, strong low-level flow should limit the waterspout threat so that a categorical risk is not deemed necessary for this area at the moment.

... S Spain ...

Model guidance hints at the development of some convection in the evening and night hours over the southern Iberian Peninsula, this development apparently being tied to DCVA-forced ascent ahead of a small vort max that skirts the peninsula late on Saturday. Shear is likely to remain quite weak, and given minimal thermodynamic support, chance of severe evolution is quite low.