000 AXNT20 KNHC 250004 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 804 PM EDT Sat Mar 24 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 2300 UTC. ...SPECIAL FEATURES... ...GALE WARNING FOR THE SOUTH-CENTRAL CARIBBEAN SEA... A combination of strong surface high pressure ridging southward along the U.S. east coast and relatively strong low pressure over northern South America supports winds to gale force near the coast of Colombia. The gale force winds will not be continuous but are expected to recur each night during the evening and overnight hours through the end of next week while this surface weather pattern persists. The next gale is forecast to commence at 00Z this evening over the area from 11N to 12N between 74W and 76W, with corresponding seas of 9 to 12 ft. For more details please see High Seas Forecasts issued by the National Weather Service under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC. This information can also be found at the following website: www.nhc.noaa.gov/marine ...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 N to NE winds are forecast to develop this evening for the following areas: Portions of the AGADIR and TARFAYA zones adjacent to the coast of Morocco. The gales are expected to continue for the next days or so until Sun evening. Winds will become strong northerly Sun night through Mon night. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from Sierra Leone on the African coast near 08N13W to 04N19W. The ITCZ continues from 04N19W to 01N30W to the northeast coast of Brazil near 02S45W. Scattered moderate and isolated strong convection is present within an area bounded by 01S05W to 03N32W to 06N11W to 01S05W. ...DISCUSSION... GULF OF MEXICO... Fair weather prevails across the entire Gulf of Mexico as 1023 mb surface high pressure centered off the Atlantic coast of N Florida near 29N78W ridges westward across the Gulf. Abundant dry air prevails as ridging at the mid and upper levels of the atmosphere extends over the Gulf. Moderate to fresh E to SE surface winds are noted over the eastern and central Gulf, while SE to S winds are observed over the western Gulf. Sea heights are highest, near 7 ft, in the NW Gulf due to the longer fetch there. The area of surface high pressure is expected to gradually shift ESE during the next several day. The high will be reinforced by stronger ridging building S along the E coast of the United States. Developing low pres over the central plains states will tighten the pressure gradient over the Gulf and cause winds to become fresh to strong on Tue. Surface troughing is expected to develop over the Yucatan Peninsula each day, then migrate W into the Bay of Campeche during the evening and nighttime hours. Otherwise, fair weather is expected to continue through the weekend as dry air remains in place. 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 web page, www.nadma.gd, for additional information. Relatively quiet conditions exist across the Caribbean Sea as mid- to upper-level ridging maintains a relatively dry and subsident weather pattern over the basin. Trade winds are strongest over the south-central waters N of the coast of Colombia. Winds are expected to reach gale force during the evening and overnight hours through Thu night and Fri morning. See the SPECIAL FEATURES section above for more details. Otherwise, ridging extending southward from along the east coast of the united States will maintain moderate to fresh NE to E winds over the Caribbean basin through the first half of next week. ATLANTIC OCEAN... A slow moving cold front enters the discussion area near 32N54W and continues southwestward to Puerto Rico. Another cold front extends SW from 32N58W to 27N63W. This front is beginning to weaken and will merge with and reinforce the first cold front. Scattered showers and isolated thunderstorms are observed along and up to 120 nm SE of the first front N of 26N. The second front has little convection associated with it. West of these fronts, surface high pressure dominates the area with NW to NE flow and cooler air covering the western Atlantic. Expansive surface high pressure dominates the central and eastern Atlantic Ocean. A strong 1032 mb high is centered over the E Atlantic just SW of the Azores near 36N30W with a ridge extending WSW to NE of the Leeward Islands near 22N57W. This high is producing moderate to fresh trade winds across a large portion of the tropical and subtropical eastern Atlantic waters N of the ITCZ and W of 25W. The fronts currently over the west-central Atlantic are expected to merge and slowly shift eastward, then weaken. Another cold front will enter the far northwestern waters late Sun through Mon in conjunction with developing low pres SE of New England. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy