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DISCUSSION
... France, parts of Germany and the Low Countries ...
Thunderstorm development will be quite widespread as diffluent upper - level streamline pattern covers France, Switzerland and parts of Germany / Low Countries. Atmosphere is only weakly capped and some diabatic heating should help to break the cap during the late morning / midday hours. Convective debris from storms which occured the night before should limit insolation but a combination of moist boundary layer and steepening mid - level lapse rates should be adequate for widespread 200 - 600 J/kg MLCAPE. GFS has surface dewpoints locally near 20 °C which could be somewhat too optimistic but a combination of persistent southerly flow from the Mediterranean during the past few days ( readings there in the mid - / upper tens ) and evapotranspiration should help to push dewpoints in the 14 - 18 °C range. We do not want to go into too many details as small scale variations of short waves and placement of the jet streaks will lead to seesaw changes. Overall best shear and strongest instability are displaced but scattered thunderstorms should evolve during the day / evening hours over the area of interest, growing upscale into numerous clusters, which move northwards. There is a risk for more organized thunderstorms over central / eastern France and W / NW Germany and the Low Countries where DLS / LLS are enhanced. We decided not to introduce a level area due too all those uncertainties but parts of the highlighted area may see an upgrade.
DISCUSSION
... France, parts of Germany and the Low Countries ...
Thunderstorm development will be quite widespread as diffluent upper - level streamline pattern covers France, Switzerland and parts of Germany / Low Countries. Atmosphere is only weakly capped and some diabatic heating should help to break the cap during the late morning / midday hours. Convective debris from storms which occured the night before should limit insolation but a combination of moist boundary layer and steepening mid - level lapse rates should be adequate for widespread 200 - 600 J/kg MLCAPE. GFS has surface dewpoints locally near 20 °C which could be somewhat too optimistic but a combination of persistent southerly flow from the Mediterranean during the past few days ( readings there in the mid - / upper tens ) and evapotranspiration should help to push dewpoints in the 14 - 18 °C range. We do not want to go into too many details as small scale variations of short waves and placement of the jet streaks will lead to seesaw changes. Overall best shear and strongest instability are displaced but scattered thunderstorms should evolve during the day / evening hours over the area of interest, growing upscale into numerous clusters, which move northwards. There is a risk for more organized thunderstorms over central / eastern France and W / NW Germany and the Low Countries where DLS / LLS are enhanced. We decided not to introduce a level area due too all those uncertainties but parts of the highlighted area may see an upgrade.
Bericht laatst bijgewerkt: 23-05-2008 21:16