Friday, April 19, 2019

Forecast Recap: April 17th and 18th Severe Weather Forecast.


If you missed my previous forecast, click here. 
 
How Did The Forecast Do?

For the second consecutive Dixie Alley event, with the results being less of a surprise than the first, the concerns portion of the forecast won out. Tornadoes did form, but were largely QLCS in nature, or on the ends of squall lines. Storms were very messy, in general. Here is the preliminary SPC storm report page. It currently lists 13 tornadoes, but that count may go up over time as damage surveys are finalized. There was lots of CAPE available for the storms to make use of, and they did so, but the established line of storms crossing into Louisiana and eastward held its strength as it pushed east. As a result, isolated tornado chances were reduced, and damaging wind became the primary concern (and it was, as evident by the 250+ damage reports).

How Did My Forecast Area Do?

Any isolated convection quickly congealed and became linear, which prevented supercells from staying discrete and becoming tornado producers, was the theme for the day once again. I picked Jackson, Mississippi as my area of interest. I came to that conclusion thinking isolated, prefrontal cells may form in an environment lending itself to producing tornadoes, but this did not occur. A confirmed tornado did form around the area in the early afternoon. This is evident on the storm relative velocity (2nd panel) and, well, the confirmed warning in pink on the warning panel. There is a very high chance that no one would see this tornado unless you happened to be right beside it. It was very heavily rain wrapped. This was the trend of the day: rain wrapped, embedded tornadoes. Predicting QLCS tornadoes is brutally difficult, if not impossible. You can predict a general area of interest, which happened to be the correct area in my case. Even being in the correct area, I likely would not have seen this tornado. There was not good enough visibility.

A screenshot of the embedded rotation to the west of Jackson, Mississippi as evident on the 2nd panel (Storm Relative Velocity).

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