1. Andy Josh Team 5 3/31/2005

11. On the plots that we made we can see broad area of vertical motion caused by absolute vorticity advectionand temperature advection. Where there are large areas of clouds, there are corresponding areas of positive temperature advection as well as positive areas of vorticity advection. This corresponds to vertical ascent of the air. Likewise, on the satellite images, there is clearing where there are negative areas of temperature advection and vorticity advection, representing downward motion. From the two satellites, the temperature advection on the 0Z image is fairly accurate. Positive thermal advection lines up well to the cloud features that are present in Wisconsin and in the Gulf states. On the other hand, there is a large cloud feature over the Rockies, which has a large area of negative thermal advection. This is leading us to believe that there are other mechanisms causing the forcing of the air in this region. On the 12Z map, temperature advection lines up well to the cloud features on the image. There is a large area of positive temperature advection on the east coast and in the gulf region. Through Southern Illinois, Indiana and Missouri, there is a broad area of clearing, which is associated to the negative temperature advection. The vorticity advection pattern on the cloud images doesn’t line up as well as the temperature advection does. For example, over Illinois and in the Midwest there is a large area of positive vorticity advection but, there is a large area of clearing in this same area. Likewise, where this is a large area of negative vorticity advection, we see clouds. Since the QG equation doesn’t take in account frontal boundries we are to suspect that this is the case where there is a front causing the lifting that the equation ignores. For the 12Z image, the same applies. There are other lifting forces causing clouds that the QG equation is not picking up one. On the satellite image we can really see how positive and negative thermal advection causes the precipitation on the radar. On the 05Z national radar image there is a large frontal boundry moving eastward. Behind the front there is a large area of negative thermal advection which causes downward motion helping to lift the air ahead of it. East of the front there is a large area of positive thermal advection, indicating lifting of air. The same is also true from the 14Z radar image. A large area of negative thermal advection is helping to lift the air that is in the area of positive thermal advection which is where we see the area of precipitation on the radar. On the 05Z radar image, the area where we have precipitation is ahead of the area where there is positive vorticity advection. Also, behind the precipitation, there is negative vorticity advection, which matches well to where there are clearer skies. On the 14Z radar image the area of precipitation lines up fairly well to the areas of positive vorticity advection. On the satellite image there is an area of PVA through Indiana and western Kentucky. As this moves eastward, we expect clouds and precipitation to form ahead of this area. On the radar image we can see the precipitation that has formed.