Hurricane Rina Briefing - Wed Oct 26 2011 - 0900 hrs
* The threat of tropical storm conditions in the Florida Keys has increased due to a northerly shift in the NHC official forecast. This is the threat of winds 39 mph or greater.* These conditions are likely to be limited to rainbands, which tend to be short in duration. The tropical storm force winds tend to be associated with wind gusts (these are peak values lasting a few seconds at a time, not many hours of sustained 40 mph winds.* The prime impacts at this time would be Saturday and Saturday night.
Note that the 3-day average error cone is approaching, but still has not reached the Florida Keys. The 3-day cone has reached the Dry Tortugas, and a threat of significant marine impacts continues for the Florida Straits west of 7 Mile Bridge Friday night through Sunday.
Possible Impacts:Rainfall: Just some very light rain showers and sprinkles were noted out in the Straits this morning, and only a brief shower or sprinkle is in the cards today. Scattered showers will develop and begin to move over the Keys late tonight and continue through Friday night. There is just slight chance of a thunderstorm at this time. While there could be a brief heavy downpour especially Friday or Friday night, we don't anticipate any heavy rainfall amounts (maybe up to a half inch). The potential for heavy rain has increased for Saturday and Saturday night, with our best estimate right now about 1 to 2 inches falling during that time. Most of that will come in the form of scattered showers and a few thunderstorms.
Winds: The chance for tropical storm force winds has risen since yesterday to 36 percent in Key West, 28 percent in Marathon, and 17 percent in Miami. At this time still, the chance of hurricane force winds anywhere in the Keys remains less than 1 percent. We still do not see a long period "sustained" tropical storm wind event.
The official NHC forecast track still remains to our south, which means we're still on the low end of the potential for tornadoes.
Tides: We are seeing our highest tides (due to moon cycles) this weekend, falling during the evening hours after sunset.
A significant threat of tropical storm-force squalls exists over the open Florida Straits west of 7 Mile Bridge Friday night through early Sunday, and given the forecast of Hurricane Rina heading close to the Yucatan Peninsula, that small vessels should avoid making westward long-distance trips toward the Yucatan.
The bottom line is that the threat of tropical storm force conditions has increased, but with a weakening tropical storm, no large area or "core" of the storm is expected to roll through the Florida Keys at this time. We have to be prepared for the possibility of tropical-storm force wind gusts (39 mph or greater) in association with squalls. These tend to be short-duration events of 1-2 hours at a time.