000 AXNT20 KNHC 201700 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 100 PM EDT Tue Mar 20 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... ...ATLANTIC OCEAN GALE WARNING... The 06-hour forecast, starting at 20/1200 UTC, is for a cold front to be along 31N80W 30N81W. Expect: N of 29N E of the cold front to 76W, SW winds 25 to 35 knots. Seas ranging from 9 feet to 12 feet. The 24-hour forecast consists of: the cold front along 31N73W TO 23N81W. N of 29N E of front to 70W, SW winds 30 to 35 knots. Seas ranging from 10 feet to 13 feet. ...GULF OF MEXICO GALE WARNING... The 06-hour forecast, starting at 20/1200 UTC, is for a cold front to be along 29N83W 21N97W. Expect: N OF 25N W of the cold front to 93W, W to NW winds 20 to 25 knots with frequent gusts to gale force within 30 nm of the coast between Suwannee Florida and Pascagoula Mississippi. Seas less than 8 feet. ...GALE WARNING for the METEO-FRANCE areas... Please refer to the METEO-FRANCE High Seas Forecast, that is listed on the website: WWW.METEOFRANCE.COM/PREVISIONS-METEO- MARINE/BULLETIN/ GRANDLARGE/METAREA2. Gale-force winds are forecast for the area that is called: AGADIR, TARFAYA, and CANARIAS. The OUTLOOK, for the 24 hours that follow the forecast that is valid until 21/1200 UTC, consists of: the persistence of a N or NE near gale or gale in: AGADIR, TARFAYA, CANARIAS, and CAP BLANC. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Sierra Leone near 08N13W, to 04N20W. The ITCZ continues from 04N20W to 01N30W, to Brazil near 03N51W. Scattered moderate convection is within 120 nm either side of the boundaries between 16W and 30W. ...DISCUSSION... GULF OF MEXICO... Please read the Special Features section for information about the gale warning in the Gulf of Mexico. Upper level westerly wind flow is moving across the open waters of the Gulf of Mexico. A cold front passes from the Florida Panhandle near 31N85W to 25N90W to N of Tampico Mexico near 23N98W. A prefrontal trough is over the SW Gulf from 24N90W to 18N93W. Isolated moderate convection is over the NE Gulf and N Florida N of 27N E of front. The current cold front will shift SE across the forecast waters, moving SE of the area by early Wednesday. High pressure will build in the wake of the front. CARIBBEAN SEA... Undersea volcano Kick'em Jenny, north of Grenada near 12.18N 61.38W, is in a state of unrest. The government of Grenada advises mariners to observe a 5 km or 3.1 nm exclusion zone around Kick'em Jenny. Please refer to the webpage, www.nadma.gd, for additional information. Broad upper level anticyclonic wind flow spans the area. A surface ridge passes from the Atlantic Ocean at 23N70W to W Cuba near 23N84W. A 1008 mb low is centered over N Colombia. The resultant surface pressure gradient will support fresh to locally strong trade winds across the south central Caribbean Sea during the next several days. Winds will reach near gale force along the NW coast of Colombia during the overnight hours. ATLANTIC OCEAN... Please read the Special Features section for information about the gale warning in the Atlantic Ocean. An upper level trough is in the central Atlantic Ocean supporting a surface trough that extends from 32N53W to 28N60W. Scattered showers are N of 27N between 46W and 50W. A surface ridge extends from a 1031 mb high pressure centered near 35N26W to 25N50W. The surface trough will move eastward today. A stronger cold front has just entered the region off the Florida coast. Winds will reach gale force north of 29N through Wednesday night as the front moves eastward. The wind speeds and sea heights will diminish on Thursday, as the front reaches from Bermuda to the Windward Passage, then continues E and weakens slowly. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa