Monday, June 28, 2010 0800 CDT

Alex’s peak surge estimate based on historical surge data #2
Monday, June 28, 2010
0800 CDT

Alex’s peak storm surge estimate based on historical surge data and the NHC forecast track and intensity:

Peak surge height estimate: 5-7 feet
Peak surge location estimate: South Padre Island, TX, early Thursday morning

Update: The NHC track shifted to the north, placing the estimated landfall about 65 nautical miles S of Brownsville, TX. Forecast intensity also increased. In addition, multiple sources indicate that Alex’s circulation is quite large.

Research through the SCIPP program identified three historical hurricanes that came off the Yucatan Peninsula, made landfall in northeast Mexico, and produced surges greater than or equal to 4-feet along the S TX coast. These events are:

Hurricane Emily
2005
Max surge: 5 feet at South Padre Island, TX
Cat 3 at landfall
Landfall wind speed 110 kts
Landfall position 75 nautical miles S of Brownsville, TX

Hurricane Gilbert
1988
Max surge: 6 feet at South Padre Island, TX
Cat 4 at landfall
Landfall wind speed 115 kts
Landfall position about 130 nautical miles S of Brownsville, TX

Unnamed Storm
1909
Max surge: 6 feet at South Padre Island, TX
Cat 3 at landfall
Landfall wind speed: 105 kts
Landfall position about 120 nautical miles S of Brownsville, TX

All three of these hurricanes produced surges between 5-6 feet at S Padre Island. Images of all three tracks are included in this blog.

The new NHC track places Alex’s landfall closer to the TX border than any of these events. Alex is forecast to be weaker than these previous events, however, because Alex’s circulation is so large, it is likely that Alex would produce a surge at least as high as these previous events.

The models still diverge considerably after 48 hours, so a drastic change in the storm track could change all of this.

Thanks!
Hurricane Hal

Disclaimer: This product is not a forecast. It is a surge estimate based on comparisons to historical storm surge events. This product is experimental and should not be used for decisions included, but not limited to, evacuations, storm preparations, insurance claims, or any decisions that may result in loss of life, injury, or personal, corporate or public economic losses. Louisiana State University, the University of Oklahoma, the SCIPP program, as well as Hal Needham and associated faculty, staff and students involved in developing this product, are not liable for any decisions that lead to injury, death, or any personal, corporate or public losses, including economic losses associated with this storm surge event.