Sunday, March 11, 2012

Slight Risk of Severe Weather Tomorrow


The Storm Prediction Center has issued a slight risk of severe weather for tomorrow as the remnant pieces of convection push away from its original position, which is in Arkansas and Texas.

To be honest, I'm not seeing it in the cards to have severe weather in the areas highlighted. A few minutes after eyeing this, I checked out the SPC's SREF ensemble suite for the 3 hour calibrated severe thunderstorm risk. It is showing nothing in the next 30 hours for the slight risk area. There is a little something showing up on the SREF's general calibrated thunderstorm outlook, but it is showing a 20% probability of storms in general. This makes me think 'Something's not right.' So I take it to the University of Illinois' WRF member suite.

All available members as the University of Illinois WRF member suite are showing general showers and a possible embedded thundershower for the area in slight risk, with the stronger storms down south. Now i'm pretty confused. The storms appear to be trying to hit at the afternoon, which is reasonable, but the WRF members are not showing action in Northeast Illinois. North Michigan looks like it will be in for a little something, but I feel like the models are not giving the NE Illinois area anything worth issuing a slight risk area for.

The NAM is finally the model I find that seems to have provoked the SPC to issue a slight risk, and here's why:

This is the Significant Tornado Parameter (STP) forecast from the 12z NAM. Values of 3 and higher are considered elevated. The NAM is showing values of up to 5 in Southeast Michigan and parts of Indiana. The 12z NAM is actually showing a higher risk than the 6z NAM, but not much higher.

Considering the lack of model agreement and potential for clouds out ahead of the storms, I'm not too keen on accepting a severe weather risk.

-Andrew

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