>April 2: Significant Tornado Threat shifts North (April 3-5 Outbreak)

>Upon immediate analyzation this morning of the Significant Tornado Parameter maps (STP), I discovered a couple new things.
1. The tornado threat had increased substantially across Central Illinois.
2. The tornado threat looms a bit larger over the Plains.
3. The tornado threat for where the storms began dropped off significantly.

However, some things stayed the same.
1. The system dropped off to the Southeast after hitting the Midwest.
2. The storms originated from the South Plains.

Just to give you an idea of how the threat shifted, below is Hour 48 from the NAM. Following that image will be hour 48 from the GFS model.

NAM 48 Hour Image above.

Now the 48 hour GFS image.

48 Hour GFS image above.

We do see a greatly differentiated threat with the models. 48 hours out is typically when the models have reached a consensus, but for difficult storms like this one, the consensus can be expected tomorrow morning.
(There is a new method for the GFS, but that is much less in terms of threat than the NAM as well. It is better to overguess and be wrong than underguess and have tragedy strike.)
I would take the NAM image, but Dr. Greg Forbes from The Weather Channel said that his specialized tornado forecast was ‘moderate to high’ a couple days ago. That is significant as his forecast is more short range.
That’s the latest update on the storms. Another one will likely be issued tonight, separate from the forecast discussion.

This entry was posted in April 3-5 2011 Severe Weather Outbreak Series. Bookmark the permalink.

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