Storm Forecast
Valid: Mon 12 Jan 2015 06:00 to Tue 13 Jan 2015 06:00 UTC
Issued: Mon 12 Jan 2015 04:03
Forecaster: VAN DER VELDE
A level 1 was issued for
SYNOPSIS
High pressure has shifted to the western Mediterranean Sea while a strong westerly flow over Western Europe is created by a deep low (about 946 hPa in GFS) over the Norwegian Sea. The cold front belonging to that low passes over the UK. Unstable cold airmasses with thundery showers arrive to Ireland, Scotland and western Norway during the evening and night.
A second active system is developing over the Aegean Sea as an upper trough cuts off and settles itself during the evening/night, with cold advection in upper and low levels meeting warm low level airmass over the Mediterranean Sea creating a sharp cold front boundary.
DISCUSSION
...Scotland to western Norway...
Average wind speeds over 25 and 30 m/s are found at 1-3 km altitude which may be brought down to the surface in downdrafts in thunderstorms and produce severe gusts. The convection may not be very organized, though.
...Aegean Sea and southern Turkey...
Along the sharp cold front convergence and vorticity will be very strong which should help spin up tornadoes under convective updrafts. An overlying jet stream together with large storm-relative helicity (>250 mē/sē) near the front support mesocyclones to aid in the tornado and hail threats in the warm airmass storms, which will likely organize along a line.
