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Rina continues to weaken; nearing landfall in Mexico

By: Dr. Jeff Masters, 2:14 PM GMT on October 27, 2011

Hurricane Rina continues to decay, thanks to strong upper-level southerly winds that have created 20 knots of wind shear and torn into the south side of the storm. A NOAA hurricane hunter aircraft is in Rina, and found top winds of 71 mph at the surface with their SFMR surface wind measurement instrument, and 62 mph at their flight level of 10,000 feet, during their first penetration through the center at 9:27 am EDT. These data suggests that Rina is on the verge of becoming a tropical storm. Visible satellite loops show that Rina is just a shell of its former self, with just a small mis-shapen lump of heavy thunderstorms near the center, no eye, and little in the way of spiral bands. Cancun radar shows disorganized heavy rain squalls are affecting the northeastern Yucatan Peninsula and surrounding the waters, and it is difficult to tell from the echoes that there is a tropical storm or hurricane out there. When Rina peaked in strength yesterday with 110 mph winds, it was the 13th strongest Atlantic hurricane so late in the season. But, because it was such a small storm, Rina was very vulnerable to the persistent wind shear of 15 - 20 knots that affected it, especially once it moved away from a "hot spot" in the ocean waters southeast of the Yucatan last night. Rina should continue to decay today, and will probably make landfall as a tropical storm with 60 - 70 mph winds late this afternoon or early this evening. So far this morning, winds at Cozumel have been under 15 mph, and the island had picked up 0.35" of rainfall as of 10 am EDT. Damage from Rina to Cozumel and Cancun should be minor, and I expect the hotels there will be open for business this weekend.

After Rina makes its closest pass by Cozumel, the storm will be too weak and shallow to "feel" the steering influence of a trough of low pressure passing to its north, and Rina will be trapped in the Western Caribbean near the coast of the Yucatan. Wind shear may be strong enough to destroy the storm by Monday. Moisture streaming to the northeast from Rina is likely to bring 1 - 3 inches of rain to the Florida Keys and South Florida over the weekend.

Figure 1. Dark clouds over paradise: a wunderground webcam from Playa Del Carmen, across the channel from Cozumel Island, shows the storm clouds from Rina approaching the island at 10:06 am EDT this morning.

Figure 2. Morning radar image of Rina from the Cancun, Mexico radar at 9:30 am EDT October 27, 2011. Image credit: Sevicio Meteorologico Nacional, Mexico.

Figure 3. True-color MODIS image of Hurricane Rina taken at 3:10 pm EDT October 26, 2011. At the time, Rina was a Category 1 hurricane with 85 mph winds. Image credit: NASA.

Elsewhere in the Atlantic
A broad region of low pressure in the Western Caribbean south of Jamaica (Invest 97L), is moving west at 10 - 15 mph. Heavy thunderstorm activity associated with 97L is disorganized and relatively modest, and NHC is no longer interested enough in 97L to generate computer model forecasts of its track. Heavy rains from 97L will spread over Honduras and Nicaragua tonight and Friday. None of the reliable computer models are developing 97L, and I don't expect development.

The NOGAPS and GFS models are predicting that a strong tropical disturbance capable of developing into a tropical depression could form off the Caribbean coast of Nicaragua 7 - 8 days from now.

There will be a new post on Rina late this afternoon.

Jeff Masters


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