000 WTNT33 KNHC 281142 TCPAT3 BULLETIN Potential Tropical Cyclone Eighteen Intermediate Advisory Number 3A NWS National Hurricane Center Miami FL AL182017 800 AM EDT Sat Oct 28 2017 ...HEAVY RAINS SPREADING NORTHWARD ACROSS CUBA AND THE CAYMAN ISLANDS TOWARD THE FLORIDA KEYS AND SOUTH FLORIDA... ...AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT EN ROUTE... SUMMARY OF 800 AM EDT...1200 UTC...INFORMATION ---------------------------------------------- LOCATION...19.7N 84.0W ABOUT 155 MI...245 KM SSW OF THE ISLE OF YOUTH ABOUT 250 MI...400 KM SSW OF HAVANA CUBA MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...NNE OR 30 DEGREES AT 10 MPH...17 KM/H MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Cuban provinces of Isla de la Juventud, La Habana, Ciudad de la Habana, Matanzas, Cienfuegos, and Villa Clara * Northwestern Bahamas A Tropical Storm Watch is in effect for... * Central Bahamas A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within the next 24 hours. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case within 36 hours. Interests in the Cayman Islands, South Florida, and the Florida Keys should monitor the progress of this system. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ At 800 AM EDT (1200 UTC), the disturbance was centered near latitude 19.7 North, longitude 84.0 West. The system is moving toward the north-northeast near 10 mph (17 km/h). A motion toward the northeast with an increase in forward speed is expected later today and continue through Sunday. On the forecast track, the center will move across western Cuba this afternoon, across the Straits of Florida tonight, and across the northwestern Bahamas Sunday morning. Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Strengthening is forecast during the next 48 hours, and the disturbance is expected to become a tropical storm later today. An Air Force Reserve reconnaissance aircraft is currently en route to assess the strength of the disturbance. * Formation chance through 48 hours...high...90 percent * Formation chance through 5 days...high...90 percent The estimated minimum central pressure is 1005 mb (29.68 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Potential Tropical Cyclone Eighteen is expected to produce the following rainfall totals: The Cayman Islands, western and central Cuba, northern Bahamas: 4 to 8 inches with isolated maximum totals of 10 inches through Sunday. These rainfall amounts may produce life threatening flash floods and landslides. South Florida, including the Keys: 2 to 4 inches with isolated maximum totals of 6 inches through Sunday. These rainfall totals may produce flash flooding, especially in urbanized areas. WIND: Tropical storm conditions are expected to first reach the warning area in Cuba later today and the northwestern Bahamas tonight. Tropical storm conditions are possible in the central Bahamas tonight or early Sunday. TORNADOES: A couple of brief tornadoes are possible across far South Florida and the Florida Keys from midday through this evening. NEXT ADVISORY ------------- Next complete advisory at 1100 AM EDT. $$ Forecaster Stewart