Fog/Stratus
In the first exercise about the qualitative estimation of fog two effects have been noted. One was the dissolution of fog/stratus in a valley in East Austria between 10.30 - 11.15. In this area CMVs cannot be recognised at all beause there is no movement. Consequently CMVs are not the right tool for such an application.
The other effect was the easternmost boundary of the fog/stratus area in Hungary which showed from 7.30 till to the end of the sequence a distinct east- southeastward advection. Also for this application the CMVs are not reliable because they are distincly influenced by the high moving clouds to the north and the south. Also for this fog application the nowcasting method with CMVs is not appropriate.
The other effect was the easternmost boundary of the fog/stratus area in Hungary which showed from 7.30 till to the end of the sequence a distinct east- southeastward advection. Also for this application the CMVs are not reliable because they are distincly influenced by the high moving clouds to the north and the south. Also for this fog application the nowcasting method with CMVs is not appropriate.
"As in the examples before, fill the table below."
| Answer Possible | No answer possible, but some hints | No answer possible | |
| Certainty of Fog Detection | |||
| Formation/Dissolution of Fog/Stratus | |||
| Arrival time of advected Fog/Stratus | |||
| Low/High/Multilevel cloud | |||
| Arrival time ofareas with drizzle/icing |
"So - in this case I was right; the CMV Nowcasting method is only important for advective situations."
"Yes; but on the other hand there are fog situations where advection is dominant - but you are right that this usually is a weaker movement and therefore also not so critical in nowcasting. The main questions of fog development and fog dissolution can only be answered by monitoring relevant RGB images. And of course again a combination of relevant numerical model parameters and satellite data will be the way foreward."
"Still, these CMVs are really helpful!"