Thursday, April 24, 2008

Late Post: Quiet Now, But Some Severe Will Develop

I finally got around to looking at weather at around 8 and saw the moderate risk and thought that the severe weather was already ongoing. It is really just beginning. There are some outflow boundary thunderstorms over Minnesota and Iowa and even eastern Nebraska. These are generally strong but not really severe because there are no dynamics really behind these storms. With the heat and humidity the outflow boundary was enough to fire them up. These should slowly weaken as the evening goes on. The area of bigger concern is the storms that are just starting to initiate in central Kansas into Nebraska. This is where three vorticies are working together to bring the dynamics like heat and moisture from the south, cold from the north, and low level jet stream energy which is also causing wind shear. These elements are allowing the storms that are developing to quickly become severe. There is a huge hail threat as there is chilly air just aloft of these storms. This could also cause very strong downburst winds with these thunderstorms. There is some wind shear so there is a brief tornado threat but it seems that storms are becoming outflow dominate fairly quickly after developing, and this is not favorable for long lasting tornadoes. Late tonight as these storms continue to move NE and the jet stream speeds up these storms will likely organize into a derecho. Tomorrow also has a severe threat. I hope to post on that by 10PM.

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