000 AXNT20 KNHC 231806 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sat Sep 23 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 1200 UTC surface analysis and satellite imagery through 1740 UTC. ...SPECIAL FEATURES... The center of Tropical Storm Ophelia, at 23/1800 UTC, is near 36.2N 77.3W. Ophelia is about 81 nm/150 km to the south of Richmond in Virginia; and about 70 nm/ 130 km to the ENE of Raleigh in North Carolina. Ophelia is moving toward the N, or 355 degrees, 11 knots. The estimated minimum central pressure is 993 mb. The maximum sustained wind speeds are 35 knots with gusts to 45 knots. The hazards that will be affecting land are: the storm surge, wind, rainfall, surf, and tornadoes. Tropical storm-force winds are: within 280 nm of the center in the NE quadrant; within 130 nm of the center in the SE quadrant; within 70 nm of the center in the SW quadrant; and within 70 nm of the center in the NW quadrant. Sea heights that are 12 feet or higher are: 300 nm of the center in the NE quadrant; within 230 nm of the center in the SE quadrant; within 180 nm of the center in the SW quadrant; and within 0 nm of the center in the NW quadrant. The maximum sea heights are 18 feet. Precipitation: widely scattered to scattered moderate, and isolated strong, is from 20N to 31N between 68W and 81W in the Straits of Florida. Other precipitation is from 34N northward between 60W and 82W, from South Carolina northward. Please, read the latest HIGH SEAS FORECAST, that is issued by the Ocean Prediction Center, at the website- https://ocean.weather.gov/shtml/NFDHSFAT1.php, and the latest Ophelia NHC Forecast/Advisory and Public Advisory, at www.hurricanes.gov, for more details. The center of Tropical Depression Seventeen, at 23/1500 UTC, is near 15.6N 38.8W. T.D. Seventeen is moving toward the W, or 270 degrees, 13 knots. The estimated minimum central pressure is 1007 mb. The maximum sustained wind speeds are 30 knots with gusts to 40 knots. Sea heights that are 12 feet or higher are within 120 nm of the center in the N semicircle. The maximum sea heights are 14 feet. Expect NE to E winds from 20 knots to 30 knots, and sea heights from 9 feet to 14 feet in E swell, within 19N38W to 19N39W to 18N41W to 17N41W to 16N38W to 17N37W to 19N38W. Expect elsewhere: winds 20 knots or less, and sea heights from 8 feet to 10 feet in NE-to-E swell, within 23N35W to 24N38W to 21N46W to 15N44W to 14N39W to 16N35W to 23N35W. Precipitation: scattered to numerous strong is from 14N to 18N between 32W and 34W. Isolated moderate to locally strong is from 05N to 21N between 27W and 54W. Please, read the latest HIGH SEAS FORECAST, that is issued by the National Hurricane Center, at the website- https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and the latest Tropical Depression Seventeen NHC Forecast/Advisory and Public Advisory, at www.hurricanes.gov, for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 19W/20W, from 20N southward, moving westward 10 knots to 15 knots. Precipitation: isolated moderate to locally strong is from 02N to 16N from 30W eastward. The monsoon trough is near the precipitation also. A Caribbean Sea tropical wave is along 64W/65W, from 22N southward, moving westward about 10 knots. Precipitation: isolated moderate is within 180 nm on either side of the tropical wave. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Guinea-Bissau near 12N16W, to 10N26W, to 14N34W. The monsoon trough also is along 14N41W 12N44W. Precipitation: isolated moderate is in the remainder of the area that is from 23N southward from 60W eastward. ...GULF OF MEXICO... A deep layer trough, and a surface trough, and cyclonic wind flow at many levels of the atmosphere are in the eastern half of the Gulf of Mexico, and continuing into the part of the Caribbean Sea that is from 15N northward from 80W westward. Precipitation: widely scattered moderate to isolated strong is from 28N southward from 90W eastward. Mostly moderate to some fresh cyclonic wind flow is in the eastern half of the Gulf of Mexico. Mostly moderate to some fresh anticyclonic wind flow is in the western half of the Gulf of Mexico. The sea heights range from 2 feet to 3 feet. A maximum of 4 feet is in the east central Gulf of Mexico. A surface trough over the southeast Gulf accompanied by scattered showers and thunderstorms will drift into the western Gulf through early next week and dissipate. Meanwhile, weak high pressure will persist over the north-central and northeast Gulf. This pattern will support gentle to moderate NE to E winds and slight seas across the basin through the middle of next week. ...CARIBBEAN SEA... A deep layer trough, and a surface trough, and cyclonic wind flow at many levels of the atmosphere are in the eastern half of the Gulf of Mexico, and continuing into the part of the Caribbean Sea that is from 15N northward from 80W westward. Precipitation: isolated moderate to locally strong is to the northwest of the line that runs from SE Nicaragua to Puerto Rico. The sea heights range from 4 feet to 5 feet to the east of the line that runs from the Windward Passage to the border of Nicaragua and Costa Rica. The comparatively highest sea heights range from 6 feet to 7 feet between 74W and 76W in the Colombia coastal waters. The sea heights range from 1 foot to 2 feet elsewhere. Fresh cyclonic wind flow is from 17N southward between 70W and 80W. Mostly moderate to some fresh cyclonic wind flow is from 70W eastward. Gentle to moderate winds are in the rest of the Caribbean Sea. The monsoon trough is along 10N75W in Colombia, southwestward, beyond Panama, into the Pacific Ocean. Precipitation: widely scattered moderate to isolated strong is from 12N southward from 73W westward. The 24-hour rainfall totals in inches, for the period that ended at 23/1200 UTC, according to the MIATPTPAN, are: 0.76 in Kingston in Jamaica; 0.38 in Guadeloupe; and 0.19 in Trinidad. Atlantic high pressure is building into the Bahamas today in the wake of Ophelia, and will support moderate to fresh trade winds across most of the eastern and central Caribbean through early next week, with fresh to strong pulses off northwest Venezuela and northeast Colombia during mainly the overnight and early morning hours. Looking ahead, seas will build in mixed NE and E swell across waters east of the Leeward Islands starting early Mon, ahead of newly formed Tropical Depression Seventeen. Seventeen is expected to turn NW next week and move into the central Atlantic. ...ATLANTIC OCEAN... Please, read the SPECIAL FEATURES section, for details about Tropical Storm Ophelia, and Tropical Depression Seventeen. A surface trough is along 26N56W 18N61W. Precipitation: widely scattered moderate to isolated strong is from 18N to 28N between 50W and 62W. Rough seas have been near this surface trough. A surface trough is along 31N25W 29N33W 27N41W. Precipitation: isolated moderate is within 90 nm on either side of the surface trough, and elsewhere from 24N northward between 20W and 42W. A dissipating stationary front is along and to the north of 31N between 45W and 65W. Precipitation: isolated moderate is from 26N northward between 40W and 68W. Weak high pressure has been maintaining gentle to moderate winds, and moderate seas in mixed swell, throughout the Atlantic Ocean. Tropical Storm Ophelia is now inland across North Carolina. Large northerly swell from Ophelia will continue to impact the waters N of 27N and W of 70W through this evening. A weak ridge will build in the wake of Ophelia off Florida through early next week, while a trough will persist across the Bahamas through Mon. Looking ahead, seas will build in mixed NE and E swell across waters northeast of the Leeward Islands starting Mon, ahead of newly formed Tropical Depression Seventeen. Tropical Depression Seventeen is near 15.6N 38.8W at 11 AM EDT, moving west at 13 kt. Maximum sustained winds are 30 kt with gusts to 40 kt. Seventeen is expected to turn NW by Tue and reach the far southeastern zones on Wed as a tropical storm. $$ mt