000 AXNT20 KNHC 172258 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 658 PM EDT Fri Mar 17 2017 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 2215 UTC. ...SPECIAL FEATURES... A strengthened pressure gradient will develop across the SW Caribbean waters by 18/0600 UTC generating near gale to gale force E-NE winds across the immediate waters offshore of northern Colombia through late tonight. See the latest NWS High Seas Forecast under WMO/AWIPS headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 07N11W to 04N20W to 02N25W. The Intertropical Convergence Zone axis extends from 02N25W to the Equator near 27W. Scattered moderate and isolated strong convection is from 04N-07N between 07W-12W. Isolated moderate convection is from 02N-11N between 18W-26W...and S of 08N between 35W-52W. ...DISCUSSION... GULF OF MEXICO... Mostly westerly flow aloft within dry and stable air prevails over the Gulf basin this evening. At the surface...overall stability continues within the southwestern periphery of a surface ridge anchored by a 1031 mb high centered along coastal Carolina near 34N78W. Moderate to occasional fresh E to SE winds prevail E of 90W and moderate to fresh SE to S winds prevail W of 90W. The ridging is forecast to fracture overnight with a piece of the high shifting southeastward into the SW North Atlc waters and the other piece of ridging drifting westward across the northern Gulf waters through Sunday. The fracturing high is a result of the next cold front expected to skirt the NE Gulf waters Saturday night and move southward across the Florida peninsula and far eastern waters into Sunday. CARIBBEAN SEA... Mostly west-southwesterly upper level flow is noted on water vapor imagery over much of the Caribbean basin this evening. This southwesterly flow over western portions feed NE into an upper level trough over the western North Atlc in support of a stationary front analyzed from western Hispaniola to western Jamaica to the NE coast of Nicaragua near 15N83W. Widely scattered showers and isolated tstms are occurring within 180 nm either side of the front. Some of the low-level moisture and isolated shower activity continues to feed across interior portions of northern Nicaragua...Honduras...and Guatemala. Otherwise...a few isolated showers are possible across the Lesser Antilles and portions of the NE Caribbean N of 13N E of 66W. Moderate to fresh trades are expected through the overnight hours into Saturday...generally E of the front...while fresh to occasional strong NE winds will prevail across the NW Caribbean through the overnight W of the front. The overall pressure gradient generating these winds is expected to relax by Sunday afternoon. ...HISPANIOLA... Southwesterly flow aloft over the island in addition to a stationary front analyzed across the NW portion of the island is providing for isolated to widely scattered showers this evening...including the adjacent coastal waters W of 70W. The front is expected to drift very slowly eastward through tonight then slide northward through Sunday become diffuse thereafter. ATLANTIC OCEAN... A cold front extends into the discussion area near 32N55W SW to 26N63W then continues stationary to the NW tip of Hispaniola and into the west-central Caribbean Sea. Scattered showers and isolated tstms are occurring N of 27N within 210 nm E of the front...and within 180 nm either side of the remainder of the front S of 27N. High pressure anchored across coastal Carolina near 34N78W is expected to continue building E-SE through Saturday. Farther east...the remainder of the central and eastern Atlc is under the influence of a surface ridge anchored by a 1034 mb high centered N of the Azores near 41N28W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN