TornadoVideos.net

Posted At: August 4, 2008 @ 9:45 AM

Posted By: Reed Timmer

The maximum sustained winds have been lowered to 40 knots in the latest advisory on Tropical Storm Edouard, because Hurricane Hunter aircraft could not find a wind observation to support a 45 knot intensity.  The latest discussion mentioned 45 knots at 850 mb on the way back from the storm, and that was the maximum wind observation.  Still though, convection has been trying to develop near the center overnight, but still looks relatively weak and disorganized coming into an unfavorable time in the diurnal cycle. 


The official NHC forecast calls for Edouard to make landfall near the Houston, TX area on Tuesday as a strong tropical storm or even a weak hurricane.  The GFDL model, for example, is showing Edouard becoming a weak hurricane, while a majority of the other models are showing strong tropical storm at landfall.  If this storm RAPIDLY intensifies over the next 12 hours, we may consider chasing it..  but right now it looks like Edouard will be weaker than our minimum threshold for deployment..

Posted At: August 3, 2008 @ 10:56 PM

Posted By: Matthew Van Every

Sunday morning at around 4:30 A.M. CDT, Sioux Falls, SD reached an "Africa Hot" temperature of 101F after being in the 70s just 10 minutes prior! Why? The cause was a convective heat burst created by a collapsing thunderstorm 10 to 20K feet above ground level. These heat burst exist where rain from storms falls through a dry air mass. This dry air mass allows the rain to evaporate which cools the air and allows it to fall faster. As the air falls to Earth it warms at about 10C per 1KM due to compressional heating. If the falling air builds enough momentum it will reach the ground and cause a heat spike of up to about 30F in just a few minutes. Below is the RUC forecast sounding for Sioux Falls, SD valid 4 A.M. (courtesy of NOAA NWS).

 

 

These heat bursts are not rare; nevertheless it is "cool" when it happens. Below is the temperature and dewpoint timeline for the automated surface observation system (ASOS) at Joe Foss Field (provided by NOAA NWS). Notice the rapid temperature rise and and the plummeting dew point.

 

IN OTHER NEWS...

Keep watching the tropics; we now have Tropical Storm Edouard just off the Gulf Coast. He is moving very slow with warm waters and there is a strong high-pressure system just to the north, don't be surprised if Edorado makes hurricane status by landfall in Texas. Also note that Edorado has the potential to affect a huge number of off shore drilling wells, if Edorado were to become an intense storm then we can expect gas prices to jump up at the pump.