EUMeTrain: Nowcasting CAL Module - RGB Nowcasting

Fronts

"Let me first recapitulate the topics and questions we tried to answer in our first basic Nowcasting with the IR image only. The questions were:

Will London "leave" the frontal cloud band and get to the rear side till 18 May/03?
Will Paris "leave" the frontal cloud band at 18/09 and get to the rear side?
Will Munich get under the influence of cloudiness of which part (conceptual model) of the frontal system?
The movement of the frontal cloud band is clearly retarded. Can you find reasons for this from the sequence of images?
Under which cloud system of the frontal system will Vienna stay at 19/00?
Is there a wave development at the cold front band and if yes, will it develop further?
Will Vienna "leave" the cloudiness of the cold front band till 19/06 and move to the rear side?
Will Budapest get under the influence of the cloudiness of the cold front cloud band till 19/ 06?

Can you answer all or at least some questions now with the air mass RGB better? "

"Well, the air mass air RGB gives more information about the structure, the quality of the cloudiness and also of the dry air behind.
Consequently all the questions "will a certain town leave the cloud band till then" cannot be answered any better can be answered better cannot be answered any better . All questions like "under which part of the cloud band a station will move in the next time" cannot be answered any better can be answered better can be answered better ."

"Right! But there were also two questions about the wave and a possible wave development. Does the air mass RGB help in this questions? What do you think?"

"This is a difficult question for a beginner like me. It can only be a help if cyclogenesis is reflected in the air masses. But this is indeed the case! Wet and dry air masses are involved in a cyclogenesis. Hoskins theory describes the sinking very dry stratospheric air which releases cyclogenesis."

"Very good! Lets look into the image sequence from 18 May/09.00 UTC to 19 May/03.00 UTC and lets look into the area extending from France across Switzerland, South Germany, Austria to Hungary. What can be seen?"

18/09.00 UTC:
There are two areas of dry air behind the frontal cloud band. One reaching from the Bay of Biscay into France and one reaching from the Netherlands into Denmark. The northern one clearly overruns the frontal cloud and is involved into a cyclogenesis there. The brownish colour representig dry air above can clearly be seen in the clouds over Denmark. The southern dry area is parallel and rather moving backward away from the frontal cloud band. Some small cells at the western cloud band border over France are there where the dry air is somewhat superimposed.
 

"So there is a clear positive impact from the RGB images!"

"Let's have a look at our table now!"

"Follow this link to go on!"