[UPDATE, 4:43 PM: Welcome, InstaPundit readers! My newest post on Dean is here. All my latest posts on Dean, as they appear, can be found here.]

Just a quick update on Hurricane Dean this afternoon. The storm appears to be going through an eyewall replacement cycle, and may weaken a bit as the cycle continues. The 2:00 PM advisory is calling for “fluctuations in intensity” during the next 24 hours. For now, Dean is still at 150 mph with a 930 mb central pressure.

Some folks, like Dr. Jeff Masters, believe Dean has “peaked” for now, while others, like Alan Sullivan, think intensification is likely once the current cycle ends. Sullivan predicts that Dean will become Cat. 5 overnight tonight. Myself, I continue to worry about a final burst of intensification tomorrow, right before it hits Jamaica, due to the extremely warm waters just east of the island.

Whether or not Dean has “peaked” for the time being, a second “peak” is likely in between Jamaica and the Yucatan, as the waters are warmer in the western Caribbean than in the eastern Caribbean. (Indeed, as Sullivan noted yesterday, Dean’s development so far is remarkable, given its location; hurricanes don’t usually get this strong in the eastern Caribbean.) The official forecast calls for slight weakening over Jamaica, followed by strengthening to a Cat. 5 with 160 mph winds in 48 hours, en route to a second landfall near Cancun.

The extent of weakening over Jamaica is a big deal, though, and highly unpredictable. Because the island is so mountainous, the weakening could be significant. It all depends on Dean’s exact track over the island. The NHC is back to forecasting a tip-to-tip direct hit on the island, but as I said yesterday, it will likely be impossible to predict the storm’s exact course vis a vis Jamaica until landfall is imminent or occurring, because of last-minute “wobbles” and such. Sullivan notes that the island itself could cause the storm to wobble: “A spinning coin on a flat surface will bounce off an obstacle. Hurricanes do this too, sometimes, though such wobbles are less likely with a fast moving storm. … Will Dean march straight over Jamaica, or swerve just enough to reduce the destruction ashore?” And later: “Dean appears to be aiming directly at Jamaica; but the Blue Mountains are like a great wedge, and they may deflect the core to one side or the other.”

The question of Dean’s exact path over (or past) Jamaica is relevant not just to the destruction on the island, and not just to Dean’s future intensity, but to Dean’s future track as well. Again, I quote Sullivan:

If Dean wobbles south of Jamaica, then it will likely cross Yucatan and head for NE Mexico, as most models predict. If Dean wobbles north of Jamaica, it will pass much closer to Cuba, perhaps even crossing the island’s western tip. In that case Texas and Louisiana will be at risk later, as a few models indicate.

The models actually came into much better agreement overnight on a final landfall between Tampico, Mexico and Corpus Christi, Texas. Even the pesky GFDL agrees now. The improved consensus is probably a result of the fact that Dean is now moving in tandem with the upper low near Florida, as you can see on the satellite loop. The hurricane slowed down, the low sped up, and now they’re in sync. This makes things a bit easier for the computers to predict. The only northern “outlier” is CLP5, which isn’t really a forecasting model at all, as explained here. All in all, the central Gulf looks much safer today than yesterday. Indeed, the Houston-Galveston area and points east are “outside the cone.”

Still, as Sullivan notes, small wobbles can have big implications, and it would behoove everyone in the Gulf to keep paying attention. It was, after all, a wholly unexpected leftward wobble over the Florida peninsula that sealed New Orleans’s fate in 2005, sending Katrina hurtling toward the central Gulf instead of the panhandle.

One final note: I’ve added some new links to my “Dean blogroll” at right. Easily the three best sources for updates, though, are the first three on the list: Jeff Masters, Eric Berger and Alan Sullivan. So if you’re looking for the latest on Dean, and I haven’t updated my blog in a while, I highly recommend their sites. As you may have noticed, at least two-thirds of my information is stolen quoted from them anyway. :)

P.S. An interesting little tidbit from the 5:00 AM discussion:

NEAR [1:00 AM EDT]…AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT REPORTED [177 MPH] FLIGHT-LEVEL WINDS IN THE NORTHERN EYEWALL OF DEAN…AND ALSO REPORTED THAT THE CENTRAL PRESSURE FELL TO 930 MB. THE FLIGHT-LEVEL WINDS COULD HAVE JUSTIFIED CALLING DEAN A CATEGORY FIVE HURRICANE. [177 mph flight levels winds would normally translate, using the standard 90% reduction formula, to 159 mph surface-level winds. -ed.] HOWEVER…DATA FROM DROPSONDES…THE STEPPED-FREQUENCY MICROWAVE RADIOMETER…AND SATELLITE INTENSITY ESTIMATES DID NOT SUPPORT THAT STATUS. THE INTENSITY WAS THUS SET [as of the 2:00 AM intermediate advisory -ed.] TO A SLIGHTLY MORE CONSERVATIVE [150 MPH]. THERE HAS BEEN LITTLE CHANGE IN THE SATELLITE APPEARANCE OF DEAN SINCE THE AIRCRAFT LEFT…SO [150 MPH] IS THE INITIAL INTENSITY FOR THIS ADVISORY.