Crown Weather Services
Tropical Weather Discussion
Issued: Thursday, September 11, 2008 700 pm EDT
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Hurricane Ike remains a very large and dangerous Category 2 hurricane this evening. Ike's current position is 26.0 North Latitude, 89.4 West Longitude. Maximum sustained winds are near 100 mph. The central pressure is 950 millibars. Ike's tiny 9-mile wide eye appears to be collapsing, which will allow a new eyewall of much larger-diameter to form. This event should allow Ike to start intensifying tonight.
The latest Tropical Cyclone Heat Potential image shows that the center of Ike has just finished crossing a cold eddy in the Gulf of Mexico waters, and is now beginning to pass along the north side of a warm eddy. This change in oceanic heat should also help allow Ike to intensify tonight.
Oceanic heat content remains moderately high after Ike crosses the eddy, which should allow some additional strengthening to continue. Wind shear of 10-15 knots and this wind shear should decrease to 5 knots by the time of landfall Saturday morning.
So, at this point, it appears Ike will make landfall somewhere between Freeport and Galveston as a Category 3 hurricane with around 120 to 130 mph winds around 2 am EDT/1 am CDT or so early Saturday morning.
All of this energy is also going into the waves in the Gulf of Mexico, and the offshore oil rigs can expect to receive one hell of a battering. At 1:50pm CDT, waves at the buoy 42001 180nm south of Louisiana peaked at 30 feet. It should be noted that the National Hurricane Center is predicting Ike's waves will peak at 50 feet in the northern Gulf on Friday.
According to the NOAA tide gauges, the storm surge along the Mississippi coast have peaked at 4 feet above normal, and are currently running 5 feet above normal on the east side of New Orleans. A storm surge of 5.9 feet was observed in New Orleans' Industrial Canal at 10:45 am CDT, and 5.75 feet in Waveland, Mississippi. Coastal Alabama is reporting a 4 to 6 foot storm surge, with 10 to 15 foot waves. Considering the center of Ike is over 250 miles south of these locations, it is very likely that the Texas coast will receive a 15 to 20 foot storm surge, even if Ike does not strengthen.
Ike will probably inundate a 250-mile stretch of the Texas coast from Port O' Connor to the Louisiana border with a 10 to 15 foot storm surge. This will occur even if Ike is a Category 1 storm at landfall. If Ike does intensify to a Category 3 or higher hurricane at landfall, storm surges of 20 feet or more are likely.
Tide levels will begin rising Friday morning and will exceed 5 feet above normal along the Upper Texas coast and along the shorelines of the bays by mid to late morning Friday. Water levels will rise rapidly beginning during the late afternoon hours of Friday as the storm surge moves in with water levels peaking Friday night and early Saturday morning.
Maximum Storm Surge Forecast:
Gulf-facing coastline west of Sargent, including Matagorda Bay: 6 to 12 feet.
Gulf-facing coastline from Sargent to Sabine Pass, including High Island, Freeport, and Galveston Island: 15 to 21 feet.
Shoreline of Galveston Bay: 15 to 25 feet with 27 feet possible on the northwest side of the head of Galveston Bay.
Life threatening storm surge flooding is likely!!!
All neighborhoods and possibly entire coastal communities will be severely flooded during the period of peak storm surge. Persons not heeding evacuation orders in single family one or two story homes will face life threatening flooding and may loose their life. Many residences of average construction directly on the coast will be destroyed. Widespread and devastating personal property damage is likely elsewhere. Vehicles left behind will likely be swept away by the water. Numerous roads will be swamped, some may be washed away by the water. Entire flood prone coastal communities will be cutoff. Water levels may exceed 9 feet for more than a mile inland. Coastal residents in multi-story facilities risk being cutoff. Conditions will be worsened by battering waves. Such waves will exacerbate property damage, with massive destruction of homes, including those of block construction.
For storm surge evacuation zone information, consult the Texas Division of Emergency Management.
Wind Forecast:
Persons who have not evacuated should plan to shelter in place in a well built structure during the period of tropical storm force winds. It is imperative that persons who live in mobile homes or poorly-built structures should evacuate to a safer location such as a well built home. Persons who live in high rises should consider evacuating as winds can be much stronger at the top of a high rise than at ground level.
Tropical storm force winds in excess of 40 mph are expected to reach the coast of Texas during Friday morning and spread inland to the Houston area by mid-afternoon Friday. Winds of at least tropical storm force will then last for up to 24 to 30 hours straight.
Hurricane force winds will reach the Texas coast during Friday evening and then the Houston Metro area around midnight Friday night. Hurricane force winds will then last for up to 12 hours straight.
Peak wind gusts of 100 to 115 mph is forecast across Harris, Liberty, Brazoria, Galveston and Chambers counties. Wind speeds in excess of 115 mph will be possible near where the center of the storm ultimately comes onshore.
Structural damage will include the majority of mobile homes being severely damaged or destroyed. Those that survive will be uninhabitable until repaired. Houses of poor to average construction will have major damage, including partial wall collapse and roofs being lifted off. Many will be uninhabitable. Well constructed houses will incur minor damage to shingles, siding, gutters, as well as blown out windows. Up to one quarter of gabled roofs will fail.
Partial roof failure is expected at Industrial Parks, especially to those buildings with light weight steel and aluminum coverings. Older low rising apartment roofs may also be torn off, as well as receiving siding and shingle damage. Up to one quarter of all glass in high rise office buildings will be blown out.
Airborne debris will cause damage, injury and possible fatalities.
Natural damage will include all trees with rotting bases becoming uprooted or snapped. Nearly all large branches will snap. Between one quarter and one half of healthy small to medium sized trees will be snapped or uprooted, most common where the ground is saturated. Up to three quarters of newly planted ground crops will be damaged.
Inland Flooding:
Widespread rainfall of 2 to 4 inches with isolated rainfall totals of up to 10 inches will be possible along the path of Ike. Significant river and stream flooding is possible in areas of heaviest rainfall.
Tornado Threat:
The threat for tornadoes will increase rapidly beginning late Friday and continue through late Saturday as Ike moves onshore. You should plan to seek shelter in an interior room on the lowest floor away from windows.
This is a very large hurricane in overall size. Tropical storm force winds extend outward up to 275 miles from the center of the storm and hurricane force winds extend outward up to 120 miles from the center of the storm. Ike's very strong winds, heavy rainfall and the threat for tornadoes will extend well inland due to the hurricane's accelerating speed at landfall. Damaging hurricane force winds are possible as far inland as 150 to 200 miles from the coast. Areas inland roughly along and east of Interstate 45 and north of Interstate 10 up to 150 to 200 miles inland will experience hurricane force winds.
Tropical storm force winds will likely extend inland to Dallas and quite possibly into southeastern Oklahoma.
In conclusion, this is a VERY DANGEROUS hurricane. A Category 3 hurricane is forecast to make landfall on the Texas coast between Freeport and Galveston around 2 am EDT/1 am CDT or so early Saturday morning. Residents under evacuation orders, please complete your preparations and leave tonight!!
This is a very serious hurricane threat. A large and destructive storm surge will cross the middle and upper Texas coast. Failure to evacuate may result in loss of life.
The next update on Hurricane Ike will be issued by 7 am EDT/6 am CDT Friday morning.
Prepared by Rob Lightbown, Crown Weather Services
