Tuesday, July 12, 2011

Weather Radar Can See You Driving!

From melting February snow in July (see post below for time lapse video) to seeing highway traffic on NEXRAD, I'm in MAJOR weathergeek mode over the past couple of days.

I hope you find this as interesting as I do.  The National Weather Service radar in North Little Rock is seeing traffic move along interstate 40 and highway 67/167.  This does not happen often as the perfect atmospheric conditions must be in place to see this.

Using radar meteorology lingo, it's known as "ducting".  The beam shoots away from the radar and increases in elevation the further away it travels due to the beam angle and the curvature of the earth.  At some point in the distance, it can hit a temperature inversion.  An inversion is simply the temperature increasing with height.  Once the radar beam hits the top of this inversion, it is bent back towards the earth and it can hit the ground.  It's doing exactly this and in velocity mode, it sees targets in motion... CARS!!!  This is the same mode we use during severe weather outbreaks when we track tornadoes.  We look for motion inside the thunderstorm moving in different directions.  Check out the radar image below.

Here is a radar image from around 7:30 this morning.  You can clearly see the traffic patterns at about the same distance from the radar along 67/167 and interstate 40.
In reflectivity mode, you can also see the traffic.  The radar thinks it's big rain drops (I wish), but it's only big rigs and cars going between Little Rock and Memphis and traffic in White county as well.

Now what about our rain chances?  We're going to have another hot day with triple digit temperatures.  There will be a disturbance rotating around the periphery of the high pressure and it could bring showers and storms Wednesday.  There will also be a frontal boundary inching towards Arkansas from the northeast.  Not everybody will get rain, but with the added cloud cover and precipitation around, temperatures may get knocked down a few degrees.  Also, don't be surprised to have a couple of severe thunderstorms.  Hail and wind would be the primary threat.  I"ll keep you updated!


Anonymous said...

So cool!!!!!

Anonymous said...

wow thats crazy . and very interseting.

Anonymous said...

Wow buddy you need some rain to talk about lol. That being said that is a cool thing.

Doug in HS said...

Someone needs to post a "Top Ten Signs You're A Weather Geek".

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