Ike Emerges Into Caribbean

The strong ridge of high pressure has steered Ike a little further west and south than previously thought, and the center emerged into the Caribbean Sea late this morning. Ike was expected to move over Cuba for almost 36 hours before finally emerging into the Gulf of Mexico. Now, it appears that Ike will mostly stay over the very warm, deep waters of the northwest Caribbean and may actually intensify again before moving over the western tip of Cuba. Strengthening is highly dependent upon the how severe the core of Ike was disrupted as it moved over land. Unfortunately, I don't have the tropical forecasting experience to know how the core of small but strong hurricanes fares as it traverses land. My best guess is that it they aren't impacted as severely as large, strong hurricanes. However, since Ike was wound up when it moved over land, it's certainly possible it may take some time before the core is repaired. It will be a learning experience for me regardless. Even with limited experience, I can confidently say that the structure of Ike looks very solid with tight banding, good inflow, and excellent outflow.


If the core is intact, it will likely strengthen quickly given the very low shear, moist ambient air, and high oceanic heat content. In fact, if this is the case, Ike could be a Category 3 hurricane again when it moves over the western tip of Cuba. This brings up another situation that deals with the interaction of the inner core and land. How will the second landfall impact the core of Ike? At this point, given my limited experience with tropical forecasting, it's best to play the conservative road and forecast Ike to be a Category 1 or perhaps 2 hurricane when it does emerge into the Gulf of Mexico.

Once into the Gulf of Mexico, strengthening will be contingent upon Ike's inner core after its second landfall in Cuba. If the core remains intact, conditions will be primed for modest and perhaps rapid intensification. Ike will be traversing the loop current and with low wind shear forecast by the models, this spells the potential for a quick ramp-up if Ike's core is intact. If it is not intact, it may take up the 48 hours before the core is repaired. This would leave Ike with approximately a 24-48 hour window to strengthen prior to landfall. In this time frame, Ike will have somewhat favorable conditions for strengthening with low shear and high oceanic heat content. The only potential caveat would be whether dry continental air becomes entrained into the circulation. This seems to happen more often than not when tropical systems approach the Texas coast. If dry air is not a problem, look for Ike to potentially become a Category 4 hurricane in the central Gulf of Mexico.

The landfall destination will have a major impact on the final intensity of Ike. A landfall along the Louisiana coast would likely result in a Category 3 hurricane as a worst case scenario. In fact, Ike would likely be weakening when it makes landfall. Conversely, a landfall in Texas could mean that Ike doesn't weaken significantly and could potentially be a Category 3 or 4. That's impossible to say at this point given the multitude of factors that govern intensity. However, the point is that a Texas landfall would imply a stronger hurricane and a Louisiana landfall would imply a weaker hurricane.

Where exactly Ike is going to make landfall is somewhat problematic, and the model guidance flip-flops are certainly not bolstering any confidence. Last night's model runs were targeting mostly Texas and Louisiana, but this morning's model runs are generally targeting Texas. The early 18Z suite of guidance is rolling in, and it generally agrees with a Texas hit. Given the strong ridge in place, and the unexpected southward jump of Ike today, it seems like Texas is a better idea at this point. Very reliable models such as the ECMWF, GFDL, UKMET, and NOGAPS now all suggest a central or south Texas coast landfall. Given the superior track record of the GFDL this season, I think landfall will be between Corpus Christi and Indianola, TX as a Category 3 hurricane.