De atmosfeer staat op ontploffen #201

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Op vrijdag 11 mei 2007 23:53 schreef Hi_flyer het volgende:

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Aardig dat je die 25+ even meldt

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Op vrijdag 11 mei 2007 19:19 schreef SpeedyGJ het volgende:
Damn

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DISCUSSION

... Belgium, the Netherlands and northern Germany .....

There are indications that a few organized thunderstorms will develop in the highlighted area.

An occluded front will cross Belgium and the Netherlands between 00Z-06Z and will traverse N-Germany during the morning hours from the SW. The front will slow down while constantly shifting NE-ward.
Moisture advection charts indicate a well mixed and humid postfrontal airmass spreading north and northeastward.
Yesterday's 18Z synop datas already show dewpoints at or above 11°C behind the front over NW France and this looks reasonable and so does the dewpoint forecast of GFS.

A dryslot, present over the English Channel at 18Z WV image , will rapdily shift eastward, reaching W-central Germany around 03Z and E-central Germany about 3 hours later. Current thinking is that a few thunderstorms will go on / develop over central Germany, moving towards the E / NE. Although weakening, lift should still be adequate for some potential instability release and models like GFS indicate a rapid increase of more surface based instability over E-central Germany between 06-12Z.
Current thinking is that combination of strong shear in an uncapped environment with steep mid-level lapse rates would be fine for an isolated large hail / tornado risk.
Storms will move / develop eastwards and should affect the Czech Republic and SW-Poland during the late morning and afternoon hours.

Further towards the north - Belgium, the Netherlands, N-Germany - the main focus for thunderstorm evolution will be the passage of a weak upper-level wave between 12Z-18Z, which will move from the SW towards the ENE.
In addition, divergence at upper-levels should increase in response of an approaching strong upper-level jet from the SW.

Environment is characterized by nice LL shear of 10-15m/s and SRH 1km values of 100-200J/kg. Mid-level lapse rates will constantly steepen and EL values indicate possible tops of up to 8km. Of particular concern will be somewhat steeper LL lapse rates as PBL gets more humid and temperatures will approach 15°C which could be fine for some enhanced LL instability release.
Environment will support storm rotation, especially if storms move off the hodograph. The main threat will be a few severe and possibly tornadic cells with an attendant hail risk .
Latest thinking is that expected storm coverage won't be so robust to issue higher probabilities but area has to be watched.

The same for NE Germany and NW Poland during the afternoon and early evening hours although easing instability release should slowly limit severe weather threat .

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Op zaterdag 12 mei 2007 10:04 schreef Adelante het volgende:
Kon je bij die eerste niet effe wachten tot die lelijke witte grafbus weg was

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Op zaterdag 12 mei 2007 15:41 schreef Crazykill het volgende:
Het waait wel hard hier in Rotterdam nu

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Op zaterdag 12 mei 2007 15:39 schreef ACT-F het volgende:

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Zo beter?

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