• A Tropical Storm Watch remains in effect for the Lower and Middle Keys from Key West to west of Channel 5 Bridge, and for the Dry Tortugas.
• Tropical Storm Rafael will move northwest with some increase in forward speed during the next few days. Rafael will continue to strengthen steadily to rapidly during the next 24 to 36 hours. Rafael is forecast to become a hurricane late today near the Cayman Islands, then move across western Cuba on Wednesday afternoon and into the extreme southeastern Gulf of Mexico Wednesday evening.
• There is moderate confidence in a forecast track across western Cuba into the southeastern Gulf of Mexico. Due to uncertainty in the exact structure and track of the storm, there remains some uncertainty in the level of potential impacts on the Florida Keys. However, these impacts may include:
o Coastal flooding, with potential saltwater flooding for oceanside portions of the Florida Keys Wednesday and Wednesday night. Water levels could reach up to 2 feet above mean higher high water, or about a foot higher than recent high tides.
o The potential for sustained tropical storm force winds is now around 3-in-5 at Key West, and just above 2-in-5 at Marathon and Layton. Tropical storm-force winds could arrive as early as predawn Wednesday morning, but will most likely arrive around midday Wednesday.
o The potential for strong/damaging sustained tropical storm force winds of 55 mph or greater ranges from just over 1-in-10 at Key West to near 1-in-20 at Marathon. The potential for sustained hurricane force winds of 74 mph or greater ranges from about 3% at Key West to 1% or less from the Saddlebunch Keys through Ocean Reef.
o There is a Slight Risk (level 2 of 5) of severe thunderstorms, including possible several tornadoes, Wednesday and Wednesday night across the Lower Keys. There is a Marginal Risk (level 1 of 5) of severe thunderstorms, including a few tornadoes, for the Middle and Upper Keys. The most potent thundery squalls will be capable of localized wind gusts of 50 to 60 mph.
o Locally heavy rainfall is possible from passing squalls, resulting in flooding of streets and poor drainage areas, especially Tuesday night through Wednesday night. Storm total rainfall likely will reach 2 to 3 inches.
• Residents and visitors in the Florida Keys should closely monitor the future progress of Rafael in the event protective actions become necessary.
The next Weather Brief concerning Tropical Storm Rafael for the Florida Keys of Monroe County will be issued by 12:00 PM EST Tuesday afternoon.
Briefings are also posted to https://www.weather.gov/media/key/DSS/dssbrief_land.pdf