Monday, June 4, 2012

Heat Burst

Hi, friends! I hope you had a great weekend.

I am going to blog all about the SPRINT TRI in my next entry.

Right now I am at work tracking severe storms and we had an interesting weather phenomenon occur in southwestern Oklahoma that several viewers have asked about.  It's called a HEAT BURST!
This graphic does a great job of explaining the weather phenomenon.  Heat bursts usually occur in the summer during the evening and overnight hours and requires a dying thunderstorm.
Dying thunderstorm - wah wah
Dry air aloft is also required.  Precipitation evaporates in this dry air.  This results in cool air that is denser than the surrounding (environmental) air.  The dense, dry air accelerates towards the ground.  The rapid descent towards the ground heats the air.  It's so fast that it doesn't have time to follow the physics that heat rises. 
Here's an example of a heat burst that happened tonight, June 3, 2012.  Severe thunderstorms developed near Childress Texas earlier in the evening and began to collapse around 10:30pm.  At 11:10pm the Oklahoma Mesonet site in Mangum recorded a temperature of 92 degrees.  Only 10 minutes earlier a neighboring Mesonet site in Hollis reported 52 mph winds.  Locally they were likely higher. 
This relative humidity graphic from the Oklahoma Mesonet site shows how dry air aloft has invaded the surface through this heat burst.  Earlier in the evening southwest Oklahoma had relative humidity percentages in the 50's.  After the heat burst, relative humidity percentages dropped to the 20s, as shown in the graphic above about 45 minutes after the heat burst.  For the nerdy specifics click here for a great website.

And now you know all about heat bursts! BOOM!

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