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Find Severe Weather or a Chase Target

Posted: Mon Apr 07, 2008 6:14 pm
by Andrew Revering
F5 can be used to easily determine where the most severe weather and initiation of severe storms may be. Here's a very simple 2 step process that I personally am willing to stake driving 600 miles to storm chase on:

1) Go through the forecast hours and look at the APRWX Severe Index
2) Once you find 'some' color on the map, then use Sea Level Pressure with Surface Wind Barb overlay, and perhaps with Temperatures and Dew Points to find the boundaries... warm front, cold front and dryline.

Where the APRWX Severe Index is closest to a portion of a boundary is where I would target for chasing, and expect the most severe storms to begin.

The APRWX Severe Index does not need to be directly over the boundary, but it's crucial to pay attention to where the boundary is. The storm will be on the boundary, not necessarily in the center of the severe index shading. If a boundary is within say 100 miles of some shading on the APRWX Severe Index map, then expect severe storms at that location on the boundary. If the boundary and the severe index are farther apart than that, then it may not happen, or it's possible you're missing a more subtle boundary closer to the shaded area. Generally storms will start on the west side or north side of the APRWX Severe Index area.

It's also important to check as many models as possible for consistency. Use the process above using NAM data, GFS data, and if it's close enough in the future, the RUC data. You may end up with different targets by looking at the different models, but you can come to a compromise after looking at it all.