Monday, September 6, 2010

Hermine Slightly Stronger on 7pm Update

The above radar image was taken from the Brownsville, TX radar about 5 minutes ago.  You can clearly see the center of Tropical Storm Hermine, which as of the 7pm National Hurricane Center advisory was located 80 miles South/Southeast of Brownsville.  Hermine is moving toward the Northwest to North/Northwest at 15 mph.  On this track, the center of Hermine is still expected to make landfall along the Mexican coast (to the South of Brownsville) later this evening.

The image below is from the same radar at the same time, except this time in "velocity" mode, which shows the strength and direction of wind blowing toward and away from the radar.  Red colors are showing winds blowing away from the radar, while green colors show winds blowing toward the radar.

The white circled area in the above image shows the center of Hermine on the velocity image.  At that distance from Brownsville, the radar beam is at about 5,500 feet above sea level near the center of the storm.  The radar was measuring winds of 72 mph near the brighter green area toward the right hand side of the white circle at the time this image was taken. (Again, remember this was at a level about 5,500 feet above sea level).

A dropsonde from a National Weather Service "hurricane hunter" aircraft measured sustained winds of 65 mph at sea level near the same location, so that is the wind speed that was used in the official 7pm advisory from the National Hurricane Center.  Hermine may still strengthen slightly before making landfall later tonight, but significant intensification is not likely since it is already nearing land.

For a more detailed analysis of the projected path of Hermine and the expected heavy rainfall impacts on Texas, see my earlier post here.

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