Figure 1. Experimental wind field analysis for Ike at 9:30 am EDT 09/12/08. The area of hurricane force winds is inside the heavy black line where the yellow color begins (64 knots). The area of tropical storm force winds is inside the heavy black line at 35 knots (turquoise colors). The total Integrated Kinetic Energy was 149 Terajoules, which makes Ike's storm surge potential a 5.4 on a scale of 1 to 6. Image credit: NOAA Hurricane Research Division.The forecastIke's small inner eyewall has completely collapsed, leaving Ike with no eyewall. Creation of a new eyewall is being hampered by some dry air to the storm's west, and the presence of about 10 knots of wind shear. However, Ike is beginning to look better organized on satellite imagery, and may still intensify by 5-10 mph before landfall. Ike will not inflict extreme wind damage like Katrina's or Rita's. The big story with Ike will be the storm surge.Ike's windsAn oil rig in Ike's path measured sustained winds of 125 mph, at 6:45 am CDT. Lower winds of 105 mph were occurring at the surface, since the rig is at an elevation of 400 feet. The Hurricane Hunters are still reporting maximum winds of 105 mph over a large region of the surface.Ike's storm surgeAccording to the NOAA tide gauges, storm tides along the Mississippi coast peaked at about 6 feet above normal yesterday, with a 7 foot storm tide observed on the east side of New Orleans at Shell Beach in Lake Borgne. At 10 am CDT, storm tides of 5-6 feet were being seen in western Louisiana, and were 5 feet at Freeport, Texas, and 5.5 feet at Galveston. According to the latest NWS forecast from the Galveston office, we can expect the following storm surges in Texas:Gulf-facing coastline west of Sargent... 4 to 6 feetShoreline of Matagorda Bay... 2 to 5 feetGulf-facing coastline from Sargent to San Luis Pass... 12 to 15 feetGulf-facing coastline San Luis Pass to High Island including Galveston Island... ... 15 to 20 feetShoreline of Galveston Bay...15 to 25 feetNOAA's experimental storm surge forecast is calling for a 10% chance that the storm tide from Ike will reach 27-30 feet on the south and east sides of Houston. The exact track of Ike is key in determining if Galveston's 17-foot sea wall gets overtopped, flooding the city. A slight wobble 30 miles to the north of Galveston would put the city into offshore winds from Ike, possibly saving it from inundation. The situation is grim for Port Arthur, Texas, on the Louisiana border. The expected storm surge of 15-20 feet will overtop the city's seawall by six feet, resulting in flooding of the city and a number of major oil refineries. Expect a significant tightening of gas supplies in coming months, due to extensive damage to the oil refineries in the Houston and Port Arthur area.Ike's winds in Houston and inlandWinds in the Houston metro area will increase to tropical storm force--39 mph--by about 4 pm CDT today, and remain that strong for about 24 hours. Category 1 hurricane force winds of about 75-85 mph will affect the city for about an 8-hour period from midnight to 8 am on Saturday. People in well-built homes will suffer only minor damage, but mobile homes and homes not build to code will suffer significant damage. The extremely long duration of the hurricane force winds will cause much greater damage than is typical for a hurricane of this strength.Winds and damage in Houston should will be slightly greater than was experienced during Hurricane Alicia of 1983. Alica had higher winds at landfall, but was a smaller storm that weakened relatively quickly inland. Ike's damage will cover a much wider area and spread farther inland, due to the large size of the storm. During Alicia, Houston Hobby Airport on the south side of the city recorded top winds of 89 mph, gusting to 99 mph. The strongest winds recorded at Houston International Airport, on the north side of the city, were 51 mph, gusting to 78 mph. Winds from Ike will probably be sustained at 85-90 mph at Houston Hobby, and 75-80 mph at Houston International Airport.A good guess on what kind of winds inland areas will experience can be had by using the Inland Wind Model developed by NOAA scientists Mark DeMaria and John Kaplan. This simple model shows the expected winds inland from the coast for the five Category hurricanes moving at different speeds. Plotted below (Figure 2) is the inland wind model plot that best fits the type of winds I expect will penetrate inland from Ike. I think Ike will be a strong Category 2 hurricane moving at about 15 mph at landfall, but the hurricane's strongest winds will penetrate farther inland than is typical due to the huge size of the storm. Thus, I picked a slightly stronger storm with a higher forward speed to base my inland wind estimate on. I expect hurricane force winds of 74 mph will penetrate about 110 miles inland, near the cities of Huntsville and Livingston to the north of Galveston, and not quite reaching Lufkin. We can expect Ike to cause the largest and longest-lived power outage in Texas history, with power knocked out along a 200-mile wide swath in eastern Texas and extreme western Louisiana extending 300 miles inland to I-20. Dallas will be at the fringe of the region of widespread power outages, and should not suffer major power failures.
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