Storm Forecast
Valid: Wed 02 Mar 2016 06:00 to Thu 03 Mar 2016 06:00 UTC
Issued: Tue 01 Mar 2016 22:53
Forecaster: PUCIK

No threat levels have been issued.

SYNOPSIS

A deep cyclonic vortex will make its way from the Atlantic towards central Europe during the day. A sharp short-wave trough associated with it is forecast to move from Ireland towards NW France. With 500 hPa temperature below -35 deg C, steep lapse rates, despite the meager low level moisture will ensure at least marginal latent instability. Another trough will be located directly over the Balkans area with strong southerly flow on its forward flank at mid to upper troposphere. DMC may develop especially over the eastern Aegean Sea, where more abundant moisture will be available.

DISCUSSION

... S UK towards NW France ...

An aforementioned sharp short-wave trough along with a cyclonically curved jet-streak are forecast to cause a strong upward motion as they rapidly pass the area between 9 and 15 UTC. However, at the lower levels, there are actually no hints of strong WAA that would add up to the synoptic-scale forcing. Marginal to low-end latent instability is forecast to develop thanks to the steep lapse rates and very limited moisture. Only a narrow belt of mixing ratios exceeding 4 g/kg is simulated. Overlap of marginal instability with strong DLS will be quite poor, especially owing to the fact that the steepest lapse rates will be located in the core of the trough, where also the weaker flow is forecast. Lvl 1 was considered for the presence of severe wind gusts with stronger cells, but was discarded due to the strengthening of low level flow only behind the tongue of enhanced instability.

... E Aegean, W / NW Turkey ...

Models simulate an overlap of low-end instability (CAPE values around or below 500 J/kg) and a strong DLS, even exceeding 30 m/s. However, upon inspecting the Tuesday 12 UTC soundings from Bucuresti and Sofia, it is obvious that the strongest shear is located near or just below the EL of the storms. Thus, it is likely that the magnitude of effective shear for the low topped storms in this case is lower than the 30 m/s in the 0-6 km. Due to this fact, we refrain from issuing a Lvl 1 for this setup. Still, stronger and better organised cells may be capable of producing hail 1 to 2 cm in diameter.