How Will El Nino Affect the Tornado Season in 2010?

Have you wondered what ramifications this present El Nino has for the 2010 tornado season? I have. At first I was excited to think of all that winter precip bringing relief to the parched South, removing drought from the equation and enhancing the moisture fetch in the spring. Now, however, I’m wondering whether that advantage won’t be offset by other concerns.

Not being a climatologist, or even modestly astute in matters of climatology, the best I can do is speculate, and my speculation is probably fraught with misinformation (aka bullcrap). Nevertheless, after looking at the Climate Prediction Center’s December 21 update of their ENSO report, I can’t help trying to make some sense of it as it pertains to storm chasing.

The report makes it clear that the present El Nino is intensifying, with sea surface temperatures (SSTs) now averaging 1.2 C above normal in the eastern Pacific.

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The six charts on page 28 of the report depicting projected sea surface temperatures caught my eye. I’ve included them here. Click on the image on the right to enlarge it.

As you read the charts, notice the following:
* Panels 3 and 4 (March-May and April-June) show above-average SSTs in the eastern Pacific, pooling significantly off of Baja.
* Slightly lower-than-average SSTs preside in most of the GOM.
* Panel 5 (May-July) shows warmer temperatures finally moving toward the coast of the GOM.
* With the June-August map, the GOM seems to be in good shape, and the SST anomaly off of Baja appears to be modifying.

What I make of this picture is that subtropical moisture from the southwest (i.e. the subtropical jet) may play a bigger-than-usual role in the springtime weather, while Gulf moisture return may be delayed. That’s not a very promising scenario for this coming storm season.

Again, I am NOT a climatologist, and all of the above is just my clumsy attempt to piece together stuff I’m aware of but don’t really understand. So chances are good that my reasoning is out in left field, and if that’s the case, then more knowledgeable heads than mine are free to correct me. I’m not attempting to make a long-term prognosis here so much as I’m simply processing information, trying to understand the big picture.

I’ve already posted on this topic in Stormtrack, in the hope of generating some discussion and gaining insight into the matter. If I glean some gems of wisdom, then a follow-up post here on Stormhorn.comĀ  may be in order. For that matter, if you’ve got a better handle on the picture than I do, then please comment here and and set me straight. Believe me, I won’t mind being wrong.

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