657 AXNT20 KNHC 181755 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Thu Aug 18 2022 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 1730 UTC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 23W/24W, from 19N southward, moving westward from 10 knots to 15 knots. Precipitation: the precipitation that is close to the tropical wave also is close to the monsoon trough. An Atlantic Ocean tropical wave is along 53W, from 19N southward, moving westward from 15 knots to 20 knots. Precipitation: isolated moderate to locally strong is within 420 nm to the west of the tropical wave from 11N southward. A weak surface trough has been in Suriname during the last 24 hours, before the arrival of the tropical wave. A tropical wave is along 88W/89W, from 20N southward, moving westward 10 knots. The wave is passing through the Yucatan Peninsula, to parts of Guatemala, Honduras, and El Salvador, into the eastern Pacific Ocean. Precipitation: scattered to numerous moderate to strong is from 17N to 20N between 87W and 91W, in the Yucatan Peninsula and in Belize, and in parts of northern Guatemala. Broken to overcast multilayered clouds, and other rainshowers, are elsewhere in the Caribbean Sea and in the Gulf of Mexico, from 12N to 23N between Jamaica and the SW Gulf of Mexico. This weather system is forecast to move through Central America and southeastern Mexico through tonight, before emerging into the SW Gulf of Mexico on Friday. It is possible that a low pressure center may form in the SW Gulf of Mexico on Friday. Additional slow development of this system is possible, while it moves northwestward in the southwestern Gulf of Mexico, through the weekend. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal areas of Senegal near 15N17W, to 12N20W 11N30W 11N37W. The ITCZ continues from 11N37W, to 12N44W 10N50W. Precipitation: disorganized isolated moderate to locally strong is from 13N southward from 60W eastward. GULF OF MEXICO... A cold front/stationary front passes through NE Florida, to the Florida coastal waters in the NE Gulf of Mexico, beyond central Louisiana. Precipitation: widely scattered moderate to isolated strong is from 25N northward, and in the coastal plains and coastal waters of U.S.A. Gulf coast states. Broad and weak surface anticyclonic wind flow spans the area. A 1014 mb high pressure center is near 27N89W. The surface pressure gradient is flat and weak. Expect light to gentle winds, and sea heights that range from 1 foot to 2 feet in the east central, the southeastern part, and in the north central Gulf of Mexico. Gentle to moderate winds, and sea heights that range from 1 foot to 3 feet, are in the northwestern, the west central, and in the northeastern Gulf of Mexico. Moderate to fresh ENE winds, and sea heights that range from 2 feet to 4 feet, are in the SW corner of the Gulf of Mexico. An upper level cyclonic circulation center is inland near 22N99W, in Mexico. A 1014 mb high pressure center, that is in the SE Louisiana offshore waters near 27N88W, will drift ESE and dissipate tonight. A cold front extending from Horseshoe Beach in Florida, NW to the coast of Mississippi, will exit the NE Gulf this evening. Rainshower activity that is associated with it will linger through Fri. A tropical wave that is in Guatemala is forecast to move across southeastern Mexico through tonight, before emerging into the Bay of Campeche on Friday, where an area of low pressure may form. Additional slow development of this system is possible, while the system moves NW, into the SW Gulf of Mexico through the weekend. Moderate to fresh E to SE winds are expected in the SW and west central Gulf of Mexico from this evening through Sat night. CARIBBEAN SEA... Broad upper level anticyclonic wind flow covers the areas that are from Jamaica westward. Comparatively drier air in subsidence in water vapor imagery covers the remainder of the area. The surface pressure gradient, based on the Atlantic Ocean surface ridge, is sustaining gentle to moderate trade winds in most of the basin. The exceptions are strong winds offshore NE Colombia and the Gulf of Venezuela, and fresh winds in the interior sections of the Gulf of Honduras. The sea heights range from 6 feet to 8 feet in the south central parts of the Caribbean Sea just to the north of Colombia. The sea heights range from 4 feet to 6 feet in the central parts of the area, and in the Gulf of Honduras. A surface trough is along 28N66W 23N67W 17N67W from the Atlantic Ocean to the Caribbean Sea. Precipitation: isolated moderate to locally strong is from 14N to 22N between 65W and 73W. A weak pressure gradient supports moderate or weaker easterly trade winds, in most of the Caribbean Sea. The exceptions are: locally fresh to strong trade winds off N Colombia and in the Gulf of Venezuela, and fresh to local strong winds in the Gulf of Honduras. The sea heights range from 3 feet to 5 feet in the south central Caribbean Sea and in the Gulf of Honduras. The sea heights range from 1 foot to 3 feet in the remainder of the area. The monsoon trough is along 10N/11N, between 74W in Colombia, and beyond the border of Costa Rica/Nicaragua, into the eastern Pacific Ocean. No significant deep convective precipitation is related directly to the monsoon trough. A tropical wave that is moving through Guatemala continues to generate numerous showers and thunderstorms in the Honduras offshore waters, and scattered showers elsewhere west of 82W. This active weather is expected to shift westward gradually through tonight, as the wave moves through southeastern Mexico, before emerging into the Bay of Campeche on Friday. Surface ridging that is building N of the region will support fresh to strong winds in the south central and parts of the SW Caribbean Sea, from today through Sat, then weaken gradually through Mon. A broad tropical wave will move through the Tropical Atlantic waters tonight, to the eastern Caribbean Sea on Fri, and to the central Caribbean Fri night and Saturday. ATLANTIC OCEAN... An upper level trough is along 63W. Cyclonic wind flow from a Bahamas inverted trough covers much of the area that is between 70W and 80W. A surface trough is along 28N66W 23N67W 17N67W from the Atlantic Ocean to the Caribbean Sea. Precipitation: isolated moderate to locally strong is from 14N to 22N between 65W and 73W, and from 28N northward between 64W and 67W. A frontal boundary is along 31N and northward between 70W and 80W. Precipitation: widely scattered moderate to isolated strong is to the northwest of the line that runs from Bermuda to Andros Island in the Bahamas. Broad surface anticyclonic wind flow covers the Atlantic Ocean from 20N northward from 60W eastward. The sea heights range from 7 feet to 9 feet from 10N northward within 400 nm of the coast of Africa. Fresh to strong NE winds are from 12N northward from 40W eastward. Moderate to fresh winds are from 13N to 27N between 40W and 60W. Gentle to moderate wind speeds are in the remainder of the Atlantic Ocean. The sea heights range from 4 feet to 6 feet elsewhere from 40W eastward, from 27N southward between 40W and 50W, and from 23N southward between 50W and 60W. The sea heights range from 2 feet to 4 feet in the remainder of the Atlantic Ocean. Surface ridging, that is building from the Azores high to the Bahamas, is expected to shift northward gradually to be along 30N through Sat, then N of the area by Mon night. A frontal boundary in the NE Florida offshore waters will linger across the region today, then move northward. Active weather N of 27N between Florida and 68W will persist through tonight. Moderate to fresh easterly winds are forecast S of 25N from Thu through Sun, as a tropical wave moves through the eastern and central Caribbean Sea. $$ mt