000 AXNT20 KNHC 180604 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Mon Sep 18 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 0540 UTC. ...SPECIAL FEATURES... The center of Tropical Storm Nigel, at 18/0300 UTC, is near 25.8N 50.2W. Nigel is moving toward the NNW, or 330 degrees, 10 knots. The estimated minimum central pressure is 992 mb. The maximum sustained wind speeds are 60 knots with gusts to 80 knots. Tropical storm-force winds are: within 120 nm of the center in the NE quadrant; within 70 nm of the center in the SE quadrant; within 50 nm of the center in the SW quadrant; and within 90 nm of the center in the NW quadrant. Sea heights that are 12 feet or higher are: 210 nm of the center in the NE quadrant; within 150 nm of the center in the SE quadrant; within 180 nm of the center in the SW quadrant; and within 150 nm of the center in the NW quadrant. The maximum sea heights are 25 feet. Precipitation: scattered to numerous strong is within 270 nm of the center in the NW semicircle. Broken to overcast multilayered clouds, and isolated moderate to locally strong, are within 900 nm of the center in the SE quadrant, and within 600 nm of the center in the NW quadrant. Rapid strengthening is forecast during the next 48 hours. It is likely for Nigel to become a hurricane overnight, and to become a major hurricane on Tuesday. Please, read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details. Please, visit www.hurricanes.gov, for the latest NHC Forecast/Advisories and Public Advisories on Nigel. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 40W, from 12N southward, moving westward 10 knots to 15 knots. Precipitation: isolated moderate to locally strong is within 900 nm to the west of the tropical wave, and within 720 nm to the east of the tropical wave. Some of this precipitation also is close to the monsoon trough and the ITCZ. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal border of Senegal and Guinea-Bissau, to 10N20W 08N29W 05N38W. The ITCZ is along 05N41W 04N49W. Precipitation: isolated moderate to locally strong from 03N to 15N from 56W eastward. Scattered moderate to widely scattered strong is from 13N to 19N between 13W and 19W. ...GULF OF MEXICO... A weakening frontal trough passes through the Florida Big Bend, into the north central Gulf of Mexico, to 25N96W. Precipitation: isolated moderate is within 180 nm to the southeast of the weakening boundary. A surface trough is in the SW corner of the Gulf of Mexico. Precipitation: isolated moderate is within 180 nm to the NW of the surface trough. A surface trough extends from the NE part of Florida to the Florida west coast just to the west of Lake Okeechobee. Precipitation: isolated moderate is in the rest of the SE corner of the area. Scattered to numerous strong is in the Atlantic Ocean, from 90 nm to 180 nm to the east of the surface trough, from 29N to 31N. The sea heights are: 2 feet off the coast of NE Mexico and off the NW coast of the Yucatan Peninsula; 1 foot elsewhere. Mostly moderate to some fresh N winds are from 26N from 89W eastward. Moderate NE winds have been in the SW corner of the Gulf of Mexico. Gentle or slower winds are in the remainder of the area. A weak trough is just inland the Texas coast will be replaced by another weak trough on Mon that moves off the Texas and over NW Gulf. The trough is expected to be accompanied by a wind shift along with a few showers and thunderstorms. Winds will be moderate or weaker with slight seas through Thu, pulsing to moderate to fresh offshore the W Yucatan in the evenings. Winds may freshen in the NE Gulf by the end of the week due to building high pressure north of the area with seas also building. ...CARIBBEAN SEA... An upper level NW-to-SE oriented trough extends from NW Cuba toward the NE Caribbean Sea. Precipitation: isolated moderate to locally strong is within 150 nm to the south of the Caribbean Sea islands from 63W westward. Moderate and fresh E and NE winds have been between 63W and the Windward Passage, and reaching the coast of Central America, during the last 24 hours. Moderate NE winds are from Honduras to the NE Yucatan Peninsula, about 180 nm to the east of land. The sea heights are: 2 feet on the Atlantic Ocean side of the eastern Caribbean Sea islands; from 3 feet to 4 feet from 80W eastward, except for 5 feet to the north of Panama; 2 feet off the coast of SE Nicaragua; 1 foot in the remainder of the Caribbean Sea. The monsoon trough is along 09N/10N from 73W in Colombia, beyond Costa Rica. Precipitation: scattered to numerous strong is within 90 nm to the north of the monsoon trough, and within 150 nm to the south of the monsoon trough, between 77W and 82W. Long period north to northeast may impact the Caribbean passages and Tropical N Atlantic through the early part of the week. Moderate to fresh trades will prevail in the central Caribbean, locally strong at times offshore northern Colombia, with moderate or weaker winds elsewhere through the week. ...ATLANTIC OCEAN... Please, read the Special Features Section, for details about Tropical Storm Nigel. A dissipating cold front passes through 26N15W to 25N22W to 31N32W. Precipitation: isolated moderate is from 20N northward from 40W eastward. Fresh to strong NE winds are from 20N northward from 30W eastward. Mostly moderate to some fresh NE winds are elsewhere from 10N northward from 40W eastward. Moderate and faster southerly winds are from 24N northward from 69W westward. Moderate southerly winds are from the monsoon trough/ITCZ southward from 50W eastward. The sea heights range from 7 feet to 9 feet from 20N from 60W westward, and from 22N northward from 35W eastward. Some heights that range from 10 feet to 12 feet are closer to Africa. The sea heights range from 4 feet to 7 feet in the remainder of the Atlantic Ocean. Tropical Storm Nigel is near 25.8N 50.2W at 11 PM EDT, and is moving north-northwest at 10 kt. Maximum sustained winds are 60 kt with gusts to 80 kt, and the minimum central pressure is 992 mb. Nigel will strengthen to a hurricane near 27.0N 51.3W Mon morning with maximum sustained winds 75 kt gusts 90 kt, continue to strengthen as it moves to near move to 28.5N 52.8W Mon evening with maximum sustained winds 90 kt gusts 110 kt, then to near 30.1N 54.2W Tue morning with maximum sustained winds 100 kt gusts 120 kt and maintain intensity as it moves north of area to near 32.1N 55.2W Tue evening. Nigel is forecast to gradually weaken as it accelerates northeastward farther away from the area through the rest of the week. Otherwise, weak ridging will prevail this evening. A cold front will move off the N Florida coast later tonight, reaching from near 31N72W to near Jupiter, Florida Tue morning, then stalling along 28N to 30N through the end of the week. Winds and seas may increase west of the stalled boundary by the end of the week as a tight pressure gradient develops due to a building high inland and a developing coastal trough off the Carolinas. $$ mt/ja