De atmosfeer staat op ontploffen #337 Regen en donder

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Op vrijdag 9 juli 2010 20:29 schreef Roel_Jewel het volgende:
Temperatuur in Eindhoven en Maastricht dik 3 graden naar beneden in korte tijd. Nog 10 graden dalen alsjeblieft...

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Op zaterdag 10 juli 2010 08:49 schreef rgn het volgende:
Nieuwe estofex kaart is binnen. Level 1 voor heel Nederland, level 2 voor het zuidoosten...
Moeten we ons opmaken voor een avondje heftig weer? Kan me er nu nog niets bij voorstellen, het is vooral erg warm

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Op zaterdag 10 juli 2010 10:09 schreef nummer_zoveel het volgende:
Het lijkt wel of het vandaag nóg warmer wordt. Het was een uur geleden al bijna niet uit te houden buiten!

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Op zaterdag 10 juli 2010 09:38 schreef Frankz0rz het volgende:
Kaart van Estofex:

[ afbeelding ]

Tot morgenochtend zie ik net

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DISCUSSION

...France, Belgium, Luxembourg and the Netherlands...

The 00Z Trappes sounding confirms the presence of a deep 14-15 g/kg moist layer in the boundary layer, which is even more than predicted by GFS 18Z (12 g/kg). The model, however, increases it to such amount during the day (18-21Z northern France, Belgium). Weakest cap is found according to GFS model LFC-LCL differences initially over C France, E Belgium and W Germany, with strongest convergence near Luxembourg, then develops a cyclonic circulation towards the evening apparently in response to the QG lifting. This low pressure center drifts off to the north or north-northwest over Belgium and Netherlands during the evening/night and will most likely be accompanied by one or more MCSs (possibly a mesoscale convective complex, MCC, given the interaction with dynamics and large instability). This scenario seems also supported by 00Z WRF models and ECMWF (Fri 12Z). The cyclonic circulation is already present before GFS develops a gridscale 'convective bomb', and is confirmed by current 04Z surface winds.
The severe weather potential is initially limited to flash floods over central France where storm motions are relatively slow and the airmass close to saturated. To the north (Belgium) 0-6 km shear is a bit higher (10-15 m/s) as well as the MLCAPE. This may already organize supercells with large hail, and after 15Z the storm-relative helicity over the lowest 3 km grows from 100 to 300 m²/s² which enhances the chance of rotating, strong updrafts. On the other hand, clustering will force the storms to coagulate into an MCS, turning the threat into mainly severe outflow winds and excessive rain. A factor which increases the wind potential from wet microburst is the large Delta-Theta-E (locally 20°). However, the storm motion will drag mostly along the boundary and shear vector direction, which may limit the spread of gusts. For this reason only a small level 2 was issued.