Storm Forecast
Storm Forecast
Valid: Sun 16 Jun 2013 06:00 to Mon 17 Jun 2013 06:00 UTC
Issued: Sun 16 Jun 2013 03:43
Forecaster: VAN DER VELDE
Valid: Sun 16 Jun 2013 06:00 to Mon 17 Jun 2013 06:00 UTC
Issued: Sun 16 Jun 2013 03:43
Forecaster: VAN DER VELDE
A level 1 was issued for France mainly for large hail.
A level 1 was issued for Alpine regions to Czechia mainly for large hail.
SYNOPSIS
A low pressure system over southern Scandinavia dominates the north side of the map with convective conditions in the cool airmass. Its cold front moves in the late morning and early afternoon into Latvia, Estonia and southern Finland. At 03Z It curves all the way back to Czechia and westward to western France with cool air at the north side. But the thermal boundary slowly starts to assume warm frontal characteristics. The main driving force is an active low SSW of Ireland which sets up a southerly low level flow over Iberia and France, quickly advecting warm air to the north. By the end of the forecast period the warm air reaches Belgium.
As is common in the onset of these situations, GFS and WRF models quickly produce strong low.level moisture out of nowhere, resulting in dewpoints over 20°C and SBCAPE values soaring to 1500.-2500 J/kg. In reality the moisture increase is not so dramatic and takes more time. The advection of steep lapse rates suggests CIN will limit the extent of convective development. There is only weak low-level forcing present over central France and eastward, so that local orography is almost the only triggering factor. With the exception of western France during the night.
A level 1 was issued for Alpine regions to Czechia mainly for large hail.
SYNOPSIS
A low pressure system over southern Scandinavia dominates the north side of the map with convective conditions in the cool airmass. Its cold front moves in the late morning and early afternoon into Latvia, Estonia and southern Finland. At 03Z It curves all the way back to Czechia and westward to western France with cool air at the north side. But the thermal boundary slowly starts to assume warm frontal characteristics. The main driving force is an active low SSW of Ireland which sets up a southerly low level flow over Iberia and France, quickly advecting warm air to the north. By the end of the forecast period the warm air reaches Belgium.
As is common in the onset of these situations, GFS and WRF models quickly produce strong low.level moisture out of nowhere, resulting in dewpoints over 20°C and SBCAPE values soaring to 1500.-2500 J/kg. In reality the moisture increase is not so dramatic and takes more time. The advection of steep lapse rates suggests CIN will limit the extent of convective development. There is only weak low-level forcing present over central France and eastward, so that local orography is almost the only triggering factor. With the exception of western France during the night.
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