Summary of typical cloud features
The main features in satellite imagery indicating the processes of a "Rapid Cyclogenesis" are (for more information compare manual Conceptual Models: Rapid Cyclogenesis ):
- During the initial stage of "rapid cyclogenesis" the following typical cloud structures can be identified:
- An (often zonally oriented) multilayered frontal cloud band associated with a baroclinic zone;
- A Warm Front Shield towards the front of the frontal cloud band;
- A cloud bulge protruding from below the frontal cloud band into the cold air consisting of lower clouds; this is indicative of an existing Wave;
- A Dark Stripe in WV imagery, along the cold side of the frontal cloud band, indicating sinking dry air with high values of PV;
- Indications for an imminent start of rapid deepening can be:
- A rapidly increasing Dark Stripe in IR and WV to the rear of the low cloud head;
- Strong negative values in motion corrected difference images (see Basics: Satelllite Channels - Artificial and Combination Channels ) indicating the drying of descending air as well as a decay in cloudiness.