30 June 2010

Alex intensifying as it makes its way to the coast...

At 03Z today (11pm EDT Tuesday), Alex was upgraded to a hurricane, the first of the season.  It is the first hurricane to form in June since Allison in 1995.  At 15Z today, the intensity as measured by aircraft was 70kts and 961mb.  [if that seems like a very low pressure for that wind speed to you, you're right!... a 961mb storm would normally have winds of 95-100kts, but Alex is large and the organization has still not matured]
Further intensification is very likely today and up to landfall.

You can view a long radar loop (from Brownsville, and going back to first eyewall view):
http://einstein.atmos.colostate.edu/~mcnoldy/tropics/alex10/Alex_30Jun10_long.gif


Landfall is expected late tonight, fortunately in a very sparsely-populated area of northern Mexico.  The closest major city is San Fernando, which should experience hurricane conditions, but is inland by about 40 miles, so it won't be affected by a storm surge.  However, the storm surge will be a bigger concern further north into Texas, such as Port Isabel,
Padre Island National Seashore, Baffin Bay, and Corpus Christi Bay.  Sea levels up to 6' above normal can be expected toward Port Isabel, and gradually decreasing further north along the coast.  Even Galveston could see a surge of 2-3', and coastal areas affected by the oil spill will also see an increase in sea level, perhaps up to 1-2'.  On top of the storm surge will be larger and more violent waves than is characteristic of the Gulf.  Both coastal and inland areas in Alex's path will experience flooding as 6-20" of rain falls in the coming days (Brownsville as ALREADY received at least 3" of rain!). And of course, there is an elevated risk of tornadoes along Alex's path, particularly in the north side of the storm.

Here are observations from a coastal station in extreme southern Texas, Port Isabel:
http://tidesonline.nos.noaa.gov/plotcomp.shtml?station_info=8779770+Port+Isabel%2C+TX

And here are wave height observations from Gulf Shores, AL, an area representative of the oil spill region:
http://www.ndbc.noaa.gov/show_plot.php?station=42012&meas=sght&uom=E&time_diff=-5&time_label=CDT


Please visit my tropical Atlantic headquarters.

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