Jeff Masters:
The outlook for Earl
Although Earl kept forecasters guessing as to exactly when it would become a tropical storm, forecast models have come into increasing solidarity on Earl's prognosis. A sprawling area of high pressure to the north of Earl will keep the storm moving on a general westerly path. Even though it will slow down a bit over the next day or two, Earl still has less than two days to gather strength before it makes landfall late Wednesday, most likely in Belize but possibly on the far southeast Mexican coast of the Yucatan peninsula. The official NHC outlook keeps Earl just below hurricane strength at landfall late Wednesday night. Wind shear is predicted by the SHIPS model to remain at a light to moderate 10 - 20 mph, although parts of the circulation are being affected by stronger shear to the north associated with a slow-moving upper-level trough over the northwest Atlantic. We will have to keep a close eye on Earl tonight and Wednesday, as sea-surface temperatures are more than 1°C above average over the northwestern Caribbean, and Earl's path will put it on the south edge of an area of of extremely high oceanic heat content that covers most of the northwest Caribbean. These waters would support rapid intensification if other conditions were favorable, although Earl may not be well enough organized to take full advantage of this oceanic rocket fuel.
The 00Z Tuesday ensemble runs of the ECMWF model were unanimous in keeping Earl as a weak tropical storm, while most members of the 06Z Tuesday GFS ensemble brought Earl up to strong tropical storm strength. The 12Z Tuesday run of the SHIPS statistical model gives Earl a 21% chance of a 24-hour increase of 25 knots in sustained winds, which would bring Earl to the threshold of hurricane status. Although the prospect is unlikely, I wouldn't be shocked to see Earl become a minimal hurricane just before landfall, as predicted by the 06Z Tuesday run of the HWRF model. We're very lucky that Earl is moving across the Caribbean so quickly, or else it could have become a much more formidable storm. If Earl remains far enough north on its trek across the Yucatan, it may have a brief window to reorganize across the southern Bay of Campeche, where the short-lived Tropical Storm Danielle formed in late June. It's worth noting that Earl will be the fifth of all five named systems in the Atlantic this year to make landfall somewhere.