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Hurricane Humberto surprises Texas and Louisiana

By: Dr. Jeff Masters, 11:58 AM GMT on September 13, 2007

A surprise Hurricane Humberto ripped into Texas near the Louisiana border this morning, bringing winds of 85 mph and torrential rains to the coast. Humberto didn't even exist yesterday morning, and grew from a tropical depression at 11am EDT to a hurricane just 14 hours later. As the hurricane intensified, it grew in size and height, allowing the storm to respond to upper-level winds that changed its course to a north-northeastly path. This allowed Humberto to stay over water parallel to the coast for the crucial hours needed for it to reach hurricane strength. Storms like Humberto give us the sobering reminder that as much as hurricane forecasting has improved in recent years, there is still much we do not understand--particularly in regards to intensity forecasting. If Humberto had had another 12-24 hours over water, it could have been a major hurricane that would have hit without enough time to evacuate those at risk.

Figure 1. Hurricane Humberto just after landfall as seen by the Lake Charles, LA radar.

Port Arthur, TX, on the border with Louisiana, has taken a heavy hit from Humberto. A portion of an apartment complex's roof was ripped off by the storm's winds, and fell on four vehicles. Widespread power outages were reported, with heavy flooding. A Personal Weather Station in downtown Port Arthur recorded a rainfall rate of over 2 inches per hour before failing at 3:30am EDT; a second station in the city recorded a minimum pressure of 989.7 mb before it, too failed. Nearby Beaumont, TX recorded sustained winds of 54 mph, gusting to 84 mph, at 5am EDT. On the coast where Humberto came ashore, McFadden wildlife Refuge measured sustained winds of 60 mph with a gust to 75 mph at 3:35am EDT. Winds of 67 mph gusting to 76 were recorded at nearby Sabine Pass. A crane at a work site at Sabine Pass recorded a wind gust of 118 mph at a height of 40 feet.

Figure 2. Current rainfall estimated by the Lake Charles radar.

While some moderate wind damage will affect Port Arthur and surrounding areas, and two tornadoes were reported near Galveston, the main threat from Humberto remains its rains. Estimated rain from the Lake Charles radar (Figure 2) show that amounts in excess of ten inches have fallen near Beaumont, with some higher amounts on the Louisiana coast over an unpopulated swampy area. Rains in excess of ten inches may fall along the path of Humberto as it plows through central Louisiana and into Mississippi. The storm may stall out and die over Mississippi, over the weekend, making for a dangerous flooding situation there. Hopefully, Humberto's rains will make it to Alabama, which is suffering its worst drought on record.

Tropical Depression Eight
Tropical Depression Eight is near tropical storm strength. This morning's QuikSCAT pass showed a circular, well-defined circulation with a believable 40 mph wind reading near the center. However, recent Satellite loops of TD 8 show that wind shear has picked up this morning, completely exposing the low level circulation center. The wind shear will need to die down and allow heavy thunderstorm activity to build near the center before TD 8 will get named.

Figure 3. Microwave image of TD 8 at 4:49am EDT. Image credit: Navy Research Lab, Monterey.

Wind shear is about 10 knots over TD 8, and is forecast to remain below 10 knots through Saturday morning, which should allow TD 8 time to grow to a modest tropical storm. Later on Saturday, the models now unanimously agree that TD 8 will encounter hostile upper-level westerly winds. The high levels of wind shear these upper-level winds will bring are likely to seriously weaken the storm, and may be able to tear it apart. It appears likely that TD 8 will pass north of the Lesser Antilles Islands, sparing them its strongest winds. Should TD 8 survive past Monday, it may represent a threat to the U.S. East Coast.

The NOAA Hurricane Hunters are scheduled to fly a research mission into TD 8 tonight.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.