Storm Forecast
Valid: Wed 28 Mar 2018 06:00 to Thu 29 Mar 2018 06:00 UTC
Issued: Tue 27 Mar 2018 20:07
Forecaster: GROENEMEIJER

A level 1 was issued across southern Turkey for extreme rainfall.

SYNOPSIS

The most important features during the forecast period are an amplified trough across the Ionian sea which develops into a cut-off low over Southwest Turkey, and a shortwave trough initially located across Ireland, that moves eastward to Germany.

DISCUSSION

Turkey...

In response to pressure falls ahead of the trough/cut-off low, northward flow is expected to increase across the eastern Mediterranean during the day. Increasingly more humid air will move northward and flow upslope across the mountains of southern Turkey. Aided by slight upper QG-forcing and low-level frontogenetic forcing, intense precipitation is expected to ensue there. Widespread accumulations of 30-60 mm, and isolated accumulations of over 100 mm are possible, which may cause local flash floods. A few rotating storms, with a modest risk of a waterspout/tornado and of marginal hail are not ruled out in the strongly-sheared environment. These may also affect Cyprus late in the period.

British Isles and West-Central Europe...

Ahead of the mid/upper trough, a cold front should move eastward across northern France. The relatively strong frontal wind shift and high-resolution NWP suggest that linear segments may develop along it. However, it is not very likely that it will be electrified as the unstable layer extends upward only to around 700 hPa. A few strong, but likely non-severe, wind gusts may occur because the system is embedded in a strong 20 m/s 850 hPa flow. Behind the system, a few isolated storms with a modest chance of lightning will develop across the UK.