Storm Forecast
Valid: Tue 29 Dec 2015 06:00 to Wed 30 Dec 2015 06:00 UTC
Issued: Tue 29 Dec 2015 00:22
Forecaster: TASZAREK

No threat levels have been issued.

SYNOPSIS and DISCUSSION

An extensive high builds up over Scandinavia and in the following days will drive in its eastern flank a cold continental air masses to parts of E and Central Europe. A deep trough (~ 950 hPa SLP) west of British Isles moves northwards and in the setup with a high over Scandinavia will provide an advection of a warm and moist polar air masses (~5C at 850 hPa) far to the north up to Svalbard. A powerful jet stream (with wind speeds up to 85 m/s) encircles a longwave that covers N Atlantic but due to a blocking high over Scandinavia will only influence a NW Europe. When considering an upper levels, a signal from PVA is forecast to pass through W Mediterranean, France, Germany and W Scandinavia. Within this signal the best conditions for the occurrence of DMC is placed over marine areas of W Mediterranean where a CAPE up to few hundredths will be available. On the other areas where an unstable air masses occurs, a marginal thermodynamic instability as well as a warm cloud tops will provide only a fractional potential for the occurrence of a lightning that do not meet the requirements for the 15% lightning probability area.

Due to lack of favorable overlap with a vertical wind shear and thermodynamic instability, a severe convective storms are unlikely over European domain. However, it is worth to mention that in the end of a forecast period a superimposing precipitation of a trough's warm section and a cold frontal boundary over the NW British Isles will pose a threat for the excessive precipitation that is forecast to continue on 30th December.