Thursday, April 18, 2013

Springs 2nd Punch Arrives Today

It's important to always remember, no two storm systems are exactly alike.  They all behave differently and no matter how much you study and analyze the data, there's more than likely going to be a curve ball thrown your way. 

The main thing I have noticed this morning is that the front may be moving a bit faster than forecast.  If you read the post below, you can see the timing of all the activity according to yesterday's (Wednesday) data.  So far it's playing out pretty close to that forecast.  Those storms in Oklahoma weakened overnight and turned into huge rain producers.  As the sun comes up and the air warms, instability levels will be on the rise.  This along with shear, will produce conditions favorable for severe weather along and ahead of the front.  Of particular concern is eastern Arkansas where daytime heating will have a chance to maximize itself.  The Storm Prediction Center has this area under a moderate risk. 

Here are the maps below.

This is hi res model data indicating a line of thunderstorms at 10AM this morning over western Arkansas.
At 1PM, the line is pushing into central Arkansas.  Any storms that can develop ahead of the front will have the ability to rotate.  Also, we'll watch for spin ups along the line.  There  could be areas where this activity "bows" out.  This is where the high wind threat will be maximized.  Notice at 1PM, eastern Arkansas is still fairly dry.  Instability is increasing there.
By 3PM, the leading edge of the line is already close to the Mississippi River so this is a bit faster than previous models. This is where the highest threat will be for all modes of severe weather.
I wanted to show you the RPM.  I'm not a big fan of this hi res model.  It runs a gazillion times (exaggeration) a day and comes up with just as many solutions sometimes.  This is at 11:30 AM showing the line through Little Rock which is faster than other models.  We'll see.
The Storm Prediction Center has much of the state in a slight risk for severe weather and the red indicates a moderate risk.
The brown area indicates a 5% chance for a tornado within 25 miles of any given point while the yellow area is a 10% chance for a tornado within 25 miles of any given point.
The biggest concern is damaging thunderstorm winds.  Look at this huge area in purple where there's a 45% chance for severe winds within 25 miles of any given point.
The yellow indicates a 15% chance for severe hail within 25 miles of any given point.

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