Friday, April 1, 2011

Significant Severe Weather Outbreak Possible April 3-5

There is definitely potential for a significant severe weather outbreak for the Plains and South Plains into next week. We at The Weather Centre have obtained new images from an excellent source on this next outbreak.
First, let's outline where thunderstorms in general may occur.
The NAM is predicting that these storms will begin due to a low pressure system in the Oklahoma area. When these storms develop, it is crucial to know where the moisture output will be. With such a defined low pressure on this map, it can be expected a good moisture output will be present in the area.
These storms will develop into a squall line as another low pressure, with warm front and subsequent squall line. This squall line could be strong and very severe, with strong tornadoes possible. This is when we turn to another map, named the STP, or Significant Tornado Parameter. Below is that map with the same time period as the image directly above.
When such a parameter is as high as it is above, there is an extreme danger in that area.
Now, we will continue to the period where this risk moves north and east.

We definitely see a resurgence in this tornado risk as the cold front takes total control. A warm front will be dragging the moisture north.
A determining factor in tornadoes is also helicity, which is when there is updraft ROTATION in supercells. Values of 250 or higher indicate the greater potential for tornadoes.
Here, we see very high values of helicity on the brunt of the storm, suggesting tornadic supercells may occur at the beginning of the squall line.
This has been an in-depth forecast. This topic will be presented again in tonight's forecast discussion.

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