Thursday, February 23, 2012

Concerning Tornado Threat Present Today in North Kentucky

I am concerned about the tornado threat in North Kentucky today. The Storm Prediction Center has outlined Kentucky, Tennessee, north Georgia and north Alabama, South Ohio and South Indiana in a slight risk of severe thunderstorms.

The GFS's forecast of the jet stream shows the Southern Jet and main Mid Latitude jet stream trying to intersect in Oklahoma. Notice how both jet streams back away from each other in Kentucky. When jet streams are forced away from each other (they would have come together in Oklahoma and stayed together through the rest of the country), it indicates a massive rising of air. In other words, a lot of instability in the atmosphere. Diverging jet streams are usually seen in the Spring and Summer with more powerful storm systems.

The SPC outlines an alarming 10% risk of a tornado in north Kentucky. Now, the SPC outlines tornado risks at low levels because no one can predict a tornado. It is impossible. That said, I have come to learn that a 10% chance of a tornado outlined by the SPC usually results in a tornado in the outlined area.

A strong jet stream will not help matters. This strong jet stream will create a lot of turbulence in the region, meaning a more dynamic and unpredictable wind pattern that will likely become more conductive for rotation in the atmosphere.

Here is a hodograph. A hodograph is basically a tracer from the area it was released to the upper points of the atmosphere. A hodograph is attached to a radiosonde, which is the instrument sent up that is attached to those big weather balloons. Anyhow, when a hodograph comes back in a circular formation, it means that there is some form of rotation action occurring in the atmosphere. We can see a half circle shape in the lower parts of the atmosphere. (The height is characterized by the distance from the first point, which in this case appears to be the dot on the left half of the image.)

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