000 AXNT20 KNHC 072106 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Fri Nov 8 2024 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 1950 UTC. ...SPECIAL FEATURES... Hurricane Rafael is centered near 24.7N 86.2W at 07/2100 UTC or 230 nm WNW of Havana Cuba, moving WNW at 8 kt. Estimated minimum central pressure is 968 mb. Maximum sustained wind speed is 90 kt with gusts to 110 kt. Peak seas are currently around 33 ft. Numerous moderate isolated strong convection is noted within 240 nm in the NE semicircle and 120 nm in the SW semicircle of Rafael. Some small intensity fluctuations are possible tonight. Weakening is forecast to begin on Fri and continue through the weekend. Rafael is forecast to move slowly over the south-central Gulf of Mexico this weekend and early next week. Interests in the southern and southwestern Gulf of Mexico should monitor the progress of this system. Swells generated by Rafael are likely to cause life- threatening surf and rip current conditions along the Gulf Coast for the next few days. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Rafael NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Excessive Rainfall Risk in Southern Central America: A low level trough induced by Hurricane Rafael that is propagating westward in the Gulf of Mexico will reach NE Nicaragua this evening. As it propagates through the region, cyclonic rotation will develop off the west coast of Nicaragua tonight and will remain stalled through the forecast period. In addition, the convective ventilation will favor the increase of moisture from the Pacific over the next few days that will enhance extreme precipitation over Costa Rica. Accumulations over central Costa Rica will potentially exceed 20 inches (500 mm) by Tue. In addition, a Central American Gyre (CAG) is forecast to develop on Fri afternoon. An abundance of moisture convergence, upper level divergence, and instability will allow for high accumulations to occur, especially in southern Panama where in excess of 10 inches (250 mm) are expected by Tue. This information is provided by the Weather Prediction Center's International desk team. Please refer to your national weather agency for details. ...TROPICAL WAVES... The axis of a tropical wave is moving from the Tropical N Atlantic Ocean into the eastern Caribbean Sea near 61W, from 15N southward near the border of Venezuela and Guyana, moving west at 15 to 20 kt. An area of scattered moderate to strong convection is east of the wave from 08N to 15N between 44W and 59W. ...MONSOON TROUGH/ITCZ... The monsoon trough briefly enters the Atlantic reaching from 10N14W to 09N15W. The ITCZ axis extends from 09N15W to 05N27W. No deep convection is noted near the monsoon trough/ITCZ. ...GULF OF MEXICO... Please see the Special Features section for details on Hurricane Rafael. Aside from conditions associated with Rafael, moderate to fresh winds and seas of 4 to 7 ft are over the NE Gulf north of 28N, while strong to near gale E winds are along the periphery of Rafael crossing 26N and extending to 27N. Seas with these winds are 10 to 17 ft. Gentle to moderate winds and seas of 2-4 ft are elsewhere, including over the western Gulf. For the forecast, Rafael will move to 24.7N 87.5W Fri morning, 24.7N 89.2W Fri afternoon, 24.8N 90.5W Sat morning, 25.0N 91.5W Sat afternoon, weaken to a tropical storm near 25.2N 92.2W Sun morning, and 25.1N 92.6W Sun afternoon. Rafael will change little in intensity as it moves over the Gulf west-central offshore waters near 23.7N 93.3W Mon afternoon. ...CARIBBEAN SEA... Moderate to fresh SE winds in the wake of Rafael are over the northwestern Caribbean north of 19N between 80W and 84W along with seas of 4 to 6 ft. Similar conditions are near the Yucatan Channel. Gentle southwest to west are elsewhere over the western Caribbean west of 84W with seas of 2 to 4 ft. Generally gentle to moderate trades are elsewhere across the basin, except for higher winds at fresh to strong speeds, NE in direction, that are south of the Dominican Republic to near 15.5N, as well as in the Mona Passage and Windward Passage. Seas with these winds are 5 to 8 ft, except for slightly higher seas of 7 to 10 ft in the Mona Passage due to a long-period NE swell. Similar seas are in and near the Anegada Passage. Elsewhere, mainly gentle to moderate winds and seas of 3 to 5 ft prevail. A large upper-level low is seen in water vapor imagery over the eastern part of the basin south of Puerto Rico near 15N67W, moving westward. Numerous moderate to isolated strong convection, with frequent lightning is pivoting around the low in its eastern semicircle. This activity is shifting across Puerto Rico and the Mona Passage to the Dominican Republic. Flooding may result from this activity as the unsettled weather is expected for the next several days. Please refer to your local national weather service for more details. To the east of the upper-level low, a surface trough extends along 64W to the north of 13N. An earlier ASCAT scatterometer pass highlighted a NE to SE wind shift of light to gentle speeds across the trough axis. Scattered showers and isolated thunderstorms are along and near the southern part of the trough. For the forecast, fresh SE winds south of western Cuba will diminish this evening as Rafael continues to move further away from the area. Gentle to moderate trade winds and slight to moderate seas are forecast elsewhere, except for fresh to strong NE winds over adjacent waters of the Dominican Republic and in the Windward Passage through Fri morning. Otherwise, large NE to E swell is forecast to enter the Atlantic passages of the NE Caribbean into Fri morning and subside afterward. ...ATLANTIC OCEAN... The pressure gradient between a broad ridge over the central and western subtropical Atlantic waters and Hurricane Rafael in the southeastern Gulf of Mexico continues to support fresh to locally strong winds east of central and southern Florida, where seas are 6 to 8 ft in E swell. The pressure gradient between the ridge and a surface trough that is along 64W and that extends south of 24N into the eastern Caribbean is supporting fresh to near gale NE to E to SE winds as seen in an earlier ASCAT scatterometer pass over that part of the ocean. These winds also cover the Atlantic waters roughly from 18N to 27N between 45W-70W. Seas with these winds are in the 8 to 12 ft range. A large area of numerous moderate to isolated strong convection exists from 15N to 24N between 51W and 68W. This area of convection is under upper- level diffluent flow that is helping to sustain it. Scattered showers and isolated thunderstorms are quickly moving westward in advance of the aforementioned large area of convection. A stationary frontal boundary is analyzed from SW of the Canary Islands through 31N19W to to weak 1015 mb low pressure near 27N27W to another 1015 mb low pressure near 24.5N31W where it begins to weaken to 22N37W. A shear line extends from that point westward to near 21N60W. An area of widespread moderate rain with embedded numerous showers is quickly lifting NNE over the NE waters north of 26N and east of 29W. Aside from the areas discussed above, moderate to fresh winds and seas of 7 to 10 ft in long-period N swell are north of the front and shear line to around 28N/29N. Light to gentle winds along with seas of 6 to 8 ft are south-southeast of the front and shear line to about 19N to the east of 55W. Mainly gentle to moderate winds and 4 to 7 ft seas prevail elsewhere, except locally fresh winds from 11N to 16N between 35W and 60W. For the forecast west of 55W, the pressure gradient between a broad ridge over the central and western subtropical Atlantic waters and a surface trough just east of Puerto Rico will support fresh to strong NE to E winds and rough seas across the offshore waters east of the central and southern Bahamas to 55W through Fri evening. The trough is also producing disorganized showers and thunderstorms over the SE offshore waters and adjacent waters of Puerto Rico and the Dominican Republic. Some gradual development of this system is possible during the next couple of days while it moves westward near the Greater Antilles. Regardless of development, locally heavy rains are possible across the northern Leeward Islands, the Virgin Islands, Puerto Rico, Hispaniola, and the southeastern Bahamas through Saturday. $$ Lewitsky