Tim Vasquez
EF5
- Joined
- Dec 4, 2003
- Messages
- 3,411
I thought I'd post this image of the impressive system currently making its way through the central United States. Shown here is a current surface analysis, revealing that this is a large occluded system. The low over Kansas is sharply occluded, with the cusp of warm air and triple point in southeast Iowa (temperatures warmer there than anyplace in Texas!). The system is rapidly trending towards a barotropic structure with the low vertically stacked with height, but there are temperature gradients still wrapping into this low. Those gradients and air masses will never fully mix and homogenize, and it won't ever reach a pure barotropic state. However it does have a definite "cold core" structure... there's a cold pool aloft over Oklahoma and that's giving classic cold core convection in that region, most of which is strongly diurnal.
Here is a visible satellite image covering mostly Oklahoma taken at 1945 UTC (2:45 pm CT) yesterday (3/21). Very beautiful spiralling of the various boundaries that have been drawn into the circulation. Usually the spiralling of a system like this is highly concentric over the oceans, but due to friction and the relative lack of homogenous air masses, the spiralling is kind of irregular. Also the stronger surface friction tends to counteract the Coriolis force (which is velocity dependent) and as a result allows mass to reach the center of the system more quickly, so central pressures do not get all that deep over land. The low-level circulation is quite obvious from the cloud cover, and you can almost certainly find the cyclone location, but note the fibrous cirrus clouds near the center... if you stare at it long enough you can get a sense of where the upper-level low is, too.
Click on the image to get a more detailed view.
Here is a visible satellite image covering mostly Oklahoma taken at 1945 UTC (2:45 pm CT) yesterday (3/21). Very beautiful spiralling of the various boundaries that have been drawn into the circulation. Usually the spiralling of a system like this is highly concentric over the oceans, but due to friction and the relative lack of homogenous air masses, the spiralling is kind of irregular. Also the stronger surface friction tends to counteract the Coriolis force (which is velocity dependent) and as a result allows mass to reach the center of the system more quickly, so central pressures do not get all that deep over land. The low-level circulation is quite obvious from the cloud cover, and you can almost certainly find the cyclone location, but note the fibrous cirrus clouds near the center... if you stare at it long enough you can get a sense of where the upper-level low is, too.
Click on the image to get a more detailed view.
