109 AXNT20 KNHC 122355 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 754 PM EDT Sun Aug 12 2018 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURE... GALE-FORCE WINDS NEAR THE COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA... NE-to-E GALE-FORCE WINDS are forecast tonight along the coast of Colombia from 11N to 13N between 70W and 76W, including in the Gulf of Venezuela. Expect sea heights to range from 9 feet to 13 feet, in the Caribbean Sea but not in the Gulf of Venezuela. Expect the GALE-FORCE wind conditions to end around sunrise on Monday, slowing down to less than gale-force. Please read the High Seas Forecast, that is listed under the WMO/AFOS headers, as FZNT02 KNHC/MIAHSFAT2, for more details. ...TROPICAL WAVES... An Atlantic tropical wave is along 19W from 19N southward. Scattered moderate rainshowers are from 05N to 10N between land and 20W. It is easily possible that some of this precipitation also is related to the monsoon trough. An Atlantic tropical wave is along 41W from 21N southward. Isolated moderate rainshowers are from 07N to 20N between 33W and 44W. It is easily possible that some of this precipitation also is related to the monsoon trough. An Atlantic tropical wave is along 52W from 21N southward. Scattered moderate rainshowers are from 07N to 11N between 49W and 61W. It is easily possible that some of this precipitation also is related to the monsoon trough. A Caribbean tropical wave is along 70W from 21N southward, from the east Hispaniola to NW Venezuela. Scattered moderate rainshowers cover the areas that are from 18N to 26N between 68W and 70W, including in eastern sections of the Dominican Republic. Isolated moderate to locally strong rainshowers are elsewhere from 12N in the Caribbean Sea to 27N in the Atlantic Ocean between 64W and 73W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Africa near 12N17W to 09N35W. The ITCZ is along 09N42W to 10N52W. Scattered moderate convection is within 75 nm south of the monsoon trough between 16W-30W. ...DISCUSSION... GULF OF MEXICO... An upper level cyclonic circulation center is near 23N98W, along the coast of Mexico. A separate area of upper level cyclonic wind flow, with a weak cyclonic circulation center/an inverted trough, spans the Gulf of Mexico from 23N southward from the Yucatan Channel westward. Upper level NE wind flow covers the rest of the Gulf of Mexico from 90W eastward. Some of the NE wind flow is related to a Bahamas upper level trough/cyclonic circulation center. Scattered moderate convection covers the Gulf of Mexico from 90W eastward. A surface ridge passes across the NW Bahamas and Lake Okeechobee, to a 1020 mb high pressure center that is near 27N89W, near the center of the Gulf of Mexico. A nocturnal trough, moving off the Yucatan Peninsula, will induce a surge of fresh to strong NE to E winds in the Bay of Campeche each night. A surface ridge will prevail elsewhere across the area. The ridge will support moderate to locally fresh SE winds in the west central and NW Gulf during most of the forecast period. CARIBBEAN SEA... Please read the SPECIAL FEATURES section for more details about the Gale Warning in effect. An upper level trough continues from the Bahamas into the entire western section of the Caribbean Sea. Upper level cyclonic wind flow covers the Caribbean Sea from the Windward Passage westward. Isolated moderate to locally strong rainshowers are to the west of the line from the Windward Passage to the northern coast of Panama that is along 80W. The monsoon trough is along 09N from 74W in Colombia beyond southern Costa Rica. Other rainshowers are possible also from 12N southward from 76W westward. Broken to overcast multilayered clouds and possible rainshowers are moving into the easternmost part of the Caribbean Sea, from 14N to 20N between 60W and 64W. High pressure, that is to the north of the area, will support fresh to strong winds in the south central Caribbean Sea through Tuesday. It is possible that sustained wind speeds may reach gale force along the coast of Colombia and in the Gulf of Venezuela tonight and Monday morning. The wind speeds and the sea heights in the Caribbean Sea will subside during the middle of the week, as the surface ridge that is in the western Atlantic Ocean weakens slightly. ATLANTIC OCEAN... An upper level inverted trough is on top of the Bahamas. Upper level cyclonic wind flow spans the Atlantic Ocean from 70W westward. Widely scattered to scattered moderate and isolated strong rainshowers cover the Bahamas and surrounding waters from 23N to 28N between 77W and 80W. Isolated moderate rainshowers are elsewhere from 70W westward. A surface ridge extends from a 1026 mb high pressure center that is near 33N34W, to 30N40W, to a 1026 mb high pressure center that is near 30N57W, to the NW Bahamas, and eventually, across Lake Okeechobee and south Florida, into the central Gulf of Mexico. The surface ridge will remain in place during the next several days. The ridge will help to maintain fresh to locally strong winds along the northern coast of Hispaniola, and in the approaches to the Windward Passage, during the evening and nighttime hours. Gentle to moderate anticyclonic wind flow will continue, elsewhere, N of 23N, and mainly moderate easterly wind flow will prevail S of 23N. 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