Severe Weather Today: 5/25/15

The Storm Prediction Center (SPC) has issued a Moderate Risk today for parts of north and central Texas, as well as southern Oklahoma.

Associated with the Moderate Risk is a 10% Tornado Threat Ring.

I am not so much doing a prediction today; severe weather is already occurring along a linear mesoscale convective system (MCS) that stretched across northern Texas and southern Oklahoma. Behind it, air has stabilized, and the severe threat diminished.

The central Texas radar shows the MCS passing through the Dallas/Fort Worth area. I am focusing on this region, as I have many friends scattered about this area.

There is a Tornado Warning near Kirvin, TX, for radar indicated rotation. The storm relative velocity has been fluctuating on the radar, so we aren’t getting the whole story.

However, the vertical image shows a clearly defined Bounded Weak Echo Region (BWER) when looking west into the storm.

I am also watching an area near Sharp, TX. There were some signs of rotation earlier, and a reported funnel cloud. There is a distinct boundary between inflow and outflow. There is an area of intense wind heading away from the radar site, so I will be watching that area. It is very close to the radar site, so the low scan will be close to ground level, and the warnings quick. However, I cannot get much of a vertical profile at this close range. You can see precipitation wrapping around some rotation just north of Sharp.

The Sharp, TX, storm has now become Tornado warned (two radar scans after the paragraph above). The rotation has become more apparent, and the Rear Flank Downdraft (RFD) is visible on radar. In fact, there is one roundish area of red reflectivities that might be a debris ball.

The Correlation Coefficient (CC) is showing some activity as well in this area. The CC compares the vertically and horizontally polarized signals; in a perfect world, this number approaches 1, meaning particles picked up on radar are mostly round, like rain drops and hail stones. Sheet metal, boards, fence posts, and other tornado debris are often longer in one direction, meaning the CC deviates from 1. Notice how there are blue, green, and yellow signatures (CC: 0.8 to 0.9) in this image in a sea of red (CC = 1). That area corresponds to the rotation on the storm relative velocity image. There very well may be a tornado in this location!

I am a little worried today for my storm chaser counter parts. The likelihood of severe weather is high, but only as a giant squall line. With many roads in this area flooded, and it being a holiday weekend near a major metropolitan area, there will be more storm chasers and less escape routes. Be careful out there, and I’ll be watching the weather from my house in New Mexico.

I will have an announcement to make in the next few days, so stay tuned.

Thank you for reading my prediction.

The Severe Weather Outlook is from the Storm Prediction Center website.
The satellite imagery is from the NOAA Satellite and Information Service.
The surface observation and upper level charts are from Unisys Weather.


About highplainschasing

This blog is about my tales in storm chasing. My name is Seth Price and I am an instrumentation instructor at New Mexico Tech. My amateur radio call sign is N3MRA.
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