...Central France, Belgium, the Netherlands, southern UK, western Germany...
Around 06 UTC, GFS hints on a new MCS that may form over southern France in the morning hours while the old system over Belgium, the Netherlands and southern UK will likely decay. Surface dewpoints in the upper tens lead to moderate instability with about 1 kJ/kg MLCAPE over central France in the afternoon. A surface low ahead of the shortwave trough over southern France will induce a very strong wind field at lower levels on its eastern flank that should support convective cells in the whole level-two area. The limiting factor will be the stratiform precipitation and mid-level cloudiness that hinder insolation over parts of central France. GFS suggests that at least a small area over eastern-central France will have low cloudiness and more than 1 kJ/kg SBCAPE may form. Given 30 m/s deep layer shear and more than 400 J/kg SRH3, isolated storms will likely be supercellular and should be capable of producing large hail and isolated strong tornadoes as LLS exceeds 20 m/s in some places and strong SRH1 is present. If the convection develops more elevated, tornadoes should be rather unlikely but widespread severe gusts may occur as 850hPa wind field is well above 15 m/s and strong downdrafts will accelerate due to evaporative cooling. Strong QG forcing and 700hPa winds exceeding 30 m/s should be adequate for a severe squall line that develops during the afternoon / evening, capable of producing widespread severe gusts with some gusts exceeding 34 m/s. The line will translate northward across the level-two area and should reach southern UK, Belgium and the Netherlands in the late evening.
Around 06 UTC, GFS hints on a new MCS that may form over southern France in the morning hours while the old system over Belgium, the Netherlands and southern UK will likely decay. Surface dewpoints in the upper tens lead to moderate instability with about 1 kJ/kg MLCAPE over central France in the afternoon. A surface low ahead of the shortwave trough over southern France will induce a very strong wind field at lower levels on its eastern flank that should support convective cells in the whole level-two area. The limiting factor will be the stratiform precipitation and mid-level cloudiness that hinder insolation over parts of central France. GFS suggests that at least a small area over eastern-central France will have low cloudiness and more than 1 kJ/kg SBCAPE may form. Given 30 m/s deep layer shear and more than 400 J/kg SRH3, isolated storms will likely be supercellular and should be capable of producing large hail and isolated strong tornadoes as LLS exceeds 20 m/s in some places and strong SRH1 is present. If the convection develops more elevated, tornadoes should be rather unlikely but widespread severe gusts may occur as 850hPa wind field is well above 15 m/s and strong downdrafts will accelerate due to evaporative cooling. Strong QG forcing and 700hPa winds exceeding 30 m/s should be adequate for a severe squall line that develops during the afternoon / evening, capable of producing widespread severe gusts with some gusts exceeding 34 m/s. The line will translate northward across the level-two area and should reach southern UK, Belgium and the Netherlands in the late evening.
Bericht laatst bijgewerkt: 27-05-2008 17:59
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