Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 7:36 PM GMT on September 07, 2008
Hurricane Ike is headed to eastern Cuba after blasting Grand Inagua Island in the southeast Bahama Islands this morning. Hurricane Hunter observations, Cuban radar, and satellite loops continue to show a that Ike remains a large and dangerous major hurricane with 120 mph winds. The latest 2:15 pm EDT center fix found a central pressure of 950 mb, up 1 mb from the 7:07 am EDT center fix. Microwave imagery (Figure 1) suggests that Ike has formed a second eyewall, concentric with its inner eyewall, and this is limiting the intensification at present. The down side of this development is that it spreads out Ike's strongest winds over a larger area, and a longer stretch of the Cuban coast will receive damaging winds.
Ike has brought heavy rain to northern Haiti, with rain rates of up to one inch per hour estimated in the mountains north of the flood-ravaged city of Gonaives (Figure 2). These torrential rains have also been affecting the southeast Bahamas and Cuba. Ike will be a devastating blow for Cuba, as the storm will be hitting one of the most heavily populated regions of the country.
Figure 1. Microwave image from 7:45 am EDT Sun 9/7/08. Image shows Ike had two concentric eyewalls. Image credit: Navy Research Lab, Monterey.
Figure 2. Estimated precipitation from Hurricane Ike at 9:04 am EDT Sun 9/7/08. Image credit: Navy Research Lab, Monterey.
Track forecast for Ike
Ike continues to move due west. A turn to the west-northwest is expected Monday. The latest 12Z (8 am EDT) computer models have not changed much from the previous set of runs. Ike is expected to track inland along the spine of Cuba for a day or longer. Along this track, Ike would likely weaken to a Category 2 or even a Category 1 hurricane. However, it would take only a very small deviation from the forecast track for Ike to spend much less time over Cuba and primarily track over the warm waters of the Florida Straits instead. None of the models are currently predicting this, but hurricane are unpredictable. I give it a 20% chance that Ike will defy the current forecast and arrive at the Keys as a major hurricane of Category 3 or 4 strength because of an unexpected wobble to the north. The SHIPS intensity model predicts Ike will be a Category 4 hurricane with 135 mph winds if this happens. The Lower Keys including Key West would be at greatest risk, and a maximum storm tide of 9-10 feet (Figure 2) could be expected in the Lower Keys in this scenario (storm tide is storm surge plus an adjustment in case Ike hits at high tide). I strongly encourage Keys residents to pay heed to the mandatory evacuation order and leave today. If Ike does spend the expected 24-36 hours over Cuba, only tropical storm or Category 1 force winds are likely in the Keys, though.
Figure 2. Expected maximum storm tide (storm surge plus adjustment for hitting at high tide) from a Category 3 hurricane moving WNW at 15 mph through the Florida Keys, hitting at high tide. This plot is an ensemble of many different hurricane tracks (shown as black lines), not just one hurricane. The maximum surge from the ensemble is plotted here. The model used is NOAA's SLOSH model. Note that oceanside surge is a foot to two feet lower than bay-side surge. Bay-side surge comes well after the storm center has passed the Keys, from the westerly winds behind the storm. Too many people have been harmed because they thought it was safe to go near the water on the bay side just after a storm has passed. Image credit: Dr. Stephen Baig, NOAA (retired).
Once Ike emerges into the Gulf of Mexico on Tuesday, a weak trough of low pressure passing to the north may be able to induce a more north-northwesterly motion to Ike, and pull it towards the Florida Panhandle, bringing tropical storm force winds to Tampa on Wednesday. The HWRF and NOGAPS models predict this, though the HWRF takes Ike further from Florida than in its previous run. The rest of the models push Ike more to the west, into the central Gulf of Mexico. The eventual landfall locations predicted by the models range from the Florida Panhandle to the South Texas coast. It is too early to guess where Ike will go at this point, since landfall is probably about 6 days away.
Intensity forecast for Ike
Ike has remained at constant intensity today, and no major changes are expected before landfall in Cuba tonight. Sea surface temperatures (SSTs) have warmed to 29.5°C underneath Ike and will warm to 30.0°C over the Gulf of Mexico. Shear has dropped below 10 knots and is expected to remain below 10 knots for the next four days. As long as Ike is not over Cuba, it has favorable conditions for intensification. Once Ike passes Cuba and enters the Gulf of Mexico, the intensification potential remains high, as shear is predicted to be below 15 knots, and the waters are hot.
Links to follow:
Holguin, Cuba radar
Punta De Maisi, Cuba weather
Punta Lucrecia, Cuba weather
Elsewhere in the tropics
The remains of Tropical Storm Josephine are near 18N, 42W, in the middle Atlantic Ocean, headed west towards the northern Lesser Antilles Islands. The storm still has some spin, but wind shear of 20 knots is preventing re-development. Wind shear is predicted to fall below 10 knots on Monday night and remain below 10 knots for several days thereafter. This may allow Josephine to regenerate later this week. The NOGAPS model predicts this will happen by Thursday, when the storm would be about 200 miles north of Puerto Rico. NHC is currently giving Josephine a low (<20%) chance of regenerating by Tuesday. These odds will probably rise by tomorrow afternoon.
The tragedy in Haiti
As Ike pounds Haiti with torrential rains today, it is clear that Haiti will need massive assistance to recover from this latest disaster. If you're looking to contribute to the cause, I recommend the Lambi Fund of Haiti charity. I've been a contributor for a number of years, and have been impressed with their leadership and aims. The charity seeks not just to provide much needed temporary food aid, but to make investments in sustainable development in an effort to restore environmental integrity and reduce poverty. One of the main places my donations have gone is to fund the purchase and planting of thousands of trees on Haiti's denuded mountainsides. These treeless slopes, missing more than 98% of their original forest cover, allow flood waters from hurricanes to rush down and cause the mind-numbing loss of life we've grown to expect with each hurricane that affects Haiti. If you're looking to help out in the country in the Western Hemisphere that needs the most help, consider a donation to the Lambi Fund.
Figure 4. The flooded city of Gonaives after Hurricane Hanna, September 3, 2008. Image credit: Lambi Fund of Haiti.
If there's an important change in the forecast for Ike, I'll have an update tonight by 9 m EDT. Otherwise, expect a new update Monday morning.
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