Storm Forecast
Valid: Fri 29 Jun 2007 06:00 to Sat 30 Jun 2007 06:00 UTC
Issued: Thu 28 Jun 2007 17:33
Forecaster: TUSCHY

SYNOPSIS

Wavy polar front jet, characterized by numerous at or above 90kt streaks and a way more zonal subtropical jet over southern Europe mint the current synoptical picture.
Infiltration of a cooler and stable / marginal unstable airmass over most parts of Europe reduces the convection threat, while hot and dry conditions prevail over most parts of the Mediterranean.
Although various shear maxima are present on European weather charts, displacement of best instability limits the overall severe weather threat.

DISCUSSION

...Extreme western Russia...

A well defined upper-level short-wave trough moves northward, reaching the White Sea during the late afternoon / early evening hours.
A combination of low to moderate instability release, 15m/s DLS and at least marginal steepened lapse rates at mid-levels point to the risk of a few hail events, although slim SRH3 values should keep the hail threat at the lower end of our severe criterion.

Parameters for more severe weather come together further towards the southeast, but this region is out of our area of responsibility and hence no further investigations were done.

...Belgium, the Netherlands...

A short discussion will be done, although ingredient based theory for convective forecast has no direct hint on possible convective development.
A signal of a slowly eastward moving, weak thermal trough is present and in combination with increasing BL moisture and strong lift, a few embedded convective segments are not out of the question. Anyway....instability should limit any convective development.

...Southern United Kingdom...

During the morning hours, stronger signals for a few thunderstorms are present as a dry slot shifts rapidly towards the east. A moist boundary layer and possible clearing should help for low-end instability release with an isolated thunderstorm threat. Low T-Td spread and enhanced LL shear could be enough for a funnel / isolated tornado report, but confidence in a more robust severe weather threat is too low for issuing higher probabilities.