000 AXNT20 KNHC 210537 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Mon Aug 21 2023 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 0000 UTC surface analysis and satellite imagery through 0535 UTC. ...SPECIAL FEATURES... Tropical Storm Franklin is centered near 14.9N 68.3W at 21/0300 UTC or 230 nm SSE of Santo Domingo Dominican Republic, moving W at 10 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Numerous moderate to strong convection is observed mainly to the east of the center, from 12N to 18N and between 62W and 70W. Seas near the center are 17 ft. Franklin is expected to produce rainfall amounts of 2 to 4 inches, with isolated higher amounts of 6 inches, across Puerto Rico through the middle of the week. Rainfall amounts of 4 to 8 inches, with isolated higher amounts up to 12 inches, will be possible across portions of Hispaniola. These rains are likely to cause flash flooding across portions of Puerto Rico and Hispaniola. Tropical Storm Emily is centered near 20.5N 40.2W at 21/0300 UTC or 960 nm WNW of the Cabo Verde Islands, moving WNW at 8 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered moderate to isolated strong convection is displaced well north of the center. Highest wave heights are 18 ft just north of the center. Newly-upgraded Tropical Storm Gert is centered near 16.7N 55.9W at 21/0400 UTC or 420 nm E of the Northern Leeward Islands, moving WNW at 8 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. The tropical storm is highly sheared with the deep convection located over the eastern quadrant. Seas near the center are 11 ft. Invest 91L is located along 86W in the eastern Gulf of Mexico, producing disorganized showers and thunderstorms. Fresh to locally strong easterly winds are evident on recent scatterometer satellite data in the eastern Gulf of Mexico. Seas in these waters are 4-7 ft. Environmental conditions appear favorable for development of this system while it moves westward at about 15 to 20 mph across the central Gulf of Mexico. A tropical depression or storm is likely to form while it approaches the western Gulf of Mexico coastline by Tuesday. Interests in the western Gulf of Mexico should monitor the progress of this system. Tropical storm watches or warnings may be necessary on Monday for portions of the southern Texas and northern Mexico coastlines. The chance of tropical development is high in the next 48 hours. Invest 92L is associated with a tropical wave located near the Cabo Verde Islands. A 1008 mb low pressure is noted along the wave near 15N24W. Isolated to scattered moderate convection is seen from 07N to 18N and east of 35W. Seas in the area described are 4-8 ft. Environmental conditions appear conducive for gradual development of this system, and a tropical depression is likely to form later this week while it moves west-northwestward across the eastern tropical Atlantic. The chance of tropical development is medium in the next 48 hours. Please, refer to the following website, www.hurricanes.gov, for more information and forecasts on all these systems. ...TROPICAL WAVES... An Atlantic Ocean tropical wave (Invest 92L) has its axis along 24W, south of 21N, moving westward at 10-15 kt. A 1008 mb low pressure is noted along the wave near 15N24W. Isolated to scattered moderate convection is seen from 07N to 18N and east of 35W. A tropical wave has its axis along 89W, south of 21N, extending from northern Yucatan, through Guatemala and El Salvador, and into the eastern Pacific. The wave is moving westward at 10-15 knots. The wave is helping to enhance the development of scattered showers and isolated thunderstorms across Yucatan and western Central America. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast of 20N16W and continues southwestward to Invest 92L near 15N24W and to 16N35W. No other convection is present aside from the convection discussed in association with Invest 92L. ...GULF OF MEXICO... Please, read the SPECIAL FEATURES section for details on Invest 91L. Aside from Invest 91L, plenty of tropical moisture and divergence aloft support isolated to scattered moderate convection across the central and western Gulf waters. The pressure gradient between the ridge positioned west of Bermuda and Invest 91L in the eastern Gulf sustain moderate to fresh easterly winds east of 90L. Seas in these waters are 4-7 ft. Elsewhere, slight to gentle winds and 1-4 ft seas prevail. For the forecast, moderate to fresh winds prevail over the eastern Gulf associated with a surface trough along 86W. Scattered showers and thunderstorms prevail in the vicinity of the trough. Additional development of this system is possible as it moves westward at about 15 to 20 kt, and a tropical depression could form as it approaches the western Gulf of Mexico coastline by Tuesday. This system has a high chance of development in 48 hours and 7 days. Regardless of development, rough seas can be expected in the central and western Gulf on Mon through Tue. ...CARIBBEAN SEA... Please, refer to the SPECIAL FEATURES section for details about Tropical Storm Franklin. A 1021 mb high pressure in the NW Atlantic is contributing to the pressure gradient across the northern semicircle of Franklin. Fresh to strong trade winds across the periphery of Franklin are N of 12N and between 63W and 73W. Seas in the waters described are 6-10 ft. Fresh to strong NE winds and seas of 4-8 ft are found in the Windward Passage and the lee of Cuba. Elsewhere, moderate or weaker winds and slight to moderate seas prevail. For the forecast, Tropical Storm Franklin is near 14.9N 68.3W at 11 PM EDT, and is moving west at 10 kt. Maximum sustained winds are 45 kt with gusts to 55 kt, and the minimum central pressure is 999 mb. Franklin will move to 15.0N 70.0W Mon morning, 15.3N 71.0W Mon evening, 16.2N 71.5W Tue morning, inland to 18.1N 71.4W Tue evening, 20.0N 70.9W Wed morning, and 21.9N 69.9W Wed evening. Franklin will change little in intensity as it moves to 24.3N 67.0W late Thu. Rough to very rough seas can be expected through Wed in the eastern and central Caribbean. ...ATLANTIC OCEAN... Please, refer to the SPECIAL FEATURES section for details on Tropical Storms Emily and Gert. A broad subtropical ridge dominates the tropical Atlantic, maintaining fairly tranquil weather conditions outside of the tropics. Moderate to fresh easterly winds are found west of 65W, along with seas of 4-7 ft. However, strong winds are noted at the entrance of the Windward Passage. Elsewhere, moderate or weaker winds and moderate seas are prevalent. For the forecast, Tropical Storm Franklin is near 14.9N 68.3W at 11 PM EDT, and is moving west at 10 kt. Maximum sustained winds are 45 kt with gusts to 55 kt, and the minimum central pressure is 999 mb. Franklin will move to 15.0N 70.0W Mon morning, 15.3N 71.0W Mon evening, 16.2N 71.5W Tue morning, inland to 18.1N 71.4W Tue evening, 20.0N 70.9W Wed morning, and 21.9N 69.9W Wed evening. Franklin will change little in intensity as it moves to the 24.3N 67.0W by late Thu. Tropical Storm Gert is near 16.7N 55.9W at 12 AM EDT, and is moving west-northwest at 8 kt. Maximum sustained winds are 35 kt with gusts to 40 kt, and the minimum central pressure is 1006 mb. Gert will weaken to a remnant low near 16.8N 57.1W this afternoon, and dissipate Tue morning. Fresh to strong tradewinds will pulse off Hispaniola and the Windward Passage each evening through Tue night. $$ DELGADO