Oct 24, 2011

DAY 146

From a depression to a hurricane in just 21 hours, Rina is now a category 1 hurricane. Impressive plumes of convection can be seen in and around the center of circulation. There is nice banding around the bottom and sides of Rina, but the northern section is still being pulled to the northeast by an escaping trough. That is the same trough that was guiding Rina to the north yesterday, but as it moves away, Rina has taken a more westward turn. 

(Hurricane Rina)
Hurricane Rina is forecast to continue strengthening. The microwave image is very revealing in that. Strong storms have built up half way around the center of circulation. That tight circulation indicates strengthening winds that are probably well in excess of 75 mph. That center will probably be able to close off over night and we should wake up to a visible eye in Rina's center tomorrow.

(Hurricane Rina on Microwave Satellite Image)
The National Hurricane Center was just as surprised as everyone else with Rina's rapid growth. They are now forecasting Rina to become a major hurricane by tomorrow night, and that's probably a safe bet given her behavior to this point. The NHC is also forecasting Rina to continue moving slowly WNW for the next 48 hours and then turn to the north just as she approaches the Yucatan. That is the result of an approaching trough from the U.S., but then they are calling for a peculiar and abrupt turn to the east. The only computer model that supports that move is the GFS which turns Rina back to the south again. 

There is still some decent among the models with the Navy model still forecasting a westward move over the Yucatan Peninsula, while the Canadian meanders Rina around and then dissipates her before she even reaches the landmass. These are unlikely scenarios, the first due to high pressure over the Yucatan, and the other due to the strength that Rina has already attained. The GFDL and the HWRF take Rina to the northeast in a more rounded fashion between Cancun and Cuba.

It is likely that Rina will be a strong hurricane on Thursday as she moves into the Yucatan landmass. There is a large swath of dry air to her north and west. There has not been much evidence of that air getting into Rina's core, but I assume that that will eventually happen. There is a surge of moisture from a tropical wave approaching quickly from the southeast. That could help supply Rina with additional water vapor. Otherwise that dry air, along with the timing of a cold front will eventually weaken Rina as she approaches the Florida Straights. 

(Hurricane Rina Water Vapor Loop)
Invest 97L is still out there. That is the moisture that is moving in on Hurricane Rina from the southeast. There still is no real organization to this system, but it does have some computer model support for future development. This Invest could be the wild card the tracking of Hurricane Rina. If 97L closes off a surface low as it moves in on a slow moving Hurricane Rina, it could cause a Fujiwara tug, pulling Rina to towards the other low. NHC is giving Invest 97L a 20% chance of becoming a tropical cyclone in the next 48 hours.

(Invest 97L)

No comments:

Post a Comment