000 AXNT20 KNHC 261748 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1248 PM EST Tue Dec 26 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...ITCZ/MONSOON TROUGH... The monsoon trough enters the Atlantic Ocean through Nigeria, Africa, and extends to 03N06W. The Intertropical Convergence Zone axis continues from 03N06W to 05N25W to the Equator near 50W. Scattered moderate convection is from 02N-07N between 24W-43W. ...DISCUSSION... GULF OF MEXICO... A weak low pressure has developed along a frontal boundary over the NW Gulf. As of 1500 UTC...the low center is located near 28N96W with a warm front extending eastward to near 26N91W. The Mosaic Doppler Radar from the SE U.S. shows scattered showers over the NW Gulf and parts of Louisiana and esatern Texas. Broken to overcast low clouds and possible isolated showers are observed across the northern Gulf waters, particularly N of 27N. A recent ASCAT pass provided observations of moderate to fresh easterly winds just N of the warm front, and mainly gentle to moderate SE-S winds across the remainder of the western half of the Gulf. A trough also extends from the low center across the far western Gulf to near 21N96W. The remainder of the Gulf is under the influence of a surface ridge anchored by a 1033 mb high currently centered over North Carolina. The ridge is providing gentle to moderate easterly winds across the eastern half of the Gulf. The area of weak low pressure across the NW Gulf will drift eastward over the next couple of days. The pressure gradient between the low and high pressure N of area will bring a slightly stronger N-NE winds on Tuesday night into Wednesday across the NW Gulf eventually becoming more diffuse by Thursday as the frontal wave weakens across the north-central and NE Gulf waters. The next strong cold front is expected to emerge off the Texas and Louisiana coasts Sunday evening followed by gale force winds. CARIBBEAN SEA... The most recent scatterometer data show fresh to strong winds across the south-central Caribbean near the coast of Colombia, and fresh to strong winds across the remainder of the central Caribbean. Moderate to fresh trades are noted elsewhere across the basin. Patches of low level moisture embedded in the trade wind flow are producing isolated to scattered passing showers across the Greater and Lesser Antilles from time to time. A larger patch of low clouds is noted over the NW Caribbean S of 20N W of 85W. Little change in this weather pattern is expected during the next couple of days. Strong trades will persist over the Central and SW Caribbean through Thursday, with near gale-force nocturnal winds near the coast of Colombia tonight. Fresh to locally strong NE winds are expected through the Windward Passage this evening. Large E swell, in the form of 7 to 9 ft seas, will reach the E Atlantic passages this evening, and continue through Thu evening. ...HISPANIOLA... Low-topped trade wind showers will continue to move across the island from time to time. Mostly dry and stable conditions are expected to persist during the next couple of days under the influence of a middle to upper level ridge and associated strong subsidence. ATLANTIC OCEAN... A cold front enters the discussion area near 31N65W extending SW to 29N71W, then becomes stationary to the NW Bahamas across the Florida Keys and into the SE Gulf of Mexico. Mainly low clouds with embedded isolated showers are associated with the frontal boundary. The cold front is expected to drift eastward through Wednesday, and begin to stall and weaken on Thursday. The remainder of central and eastern Atlantic is under the influence of a surface ridge anchored by a 1034 mb high centered SW of the Azores near 36N31W. This system will undergo occasional intensity fluctuations, resulting in a rather tight pressure gradient across the waters north of the ITCZ/monsoon trough between the coast of Africa and the Lesser Antilles through at least Wednesday. The high will move SE and weaken some on Thursday. Recent ASCAT passes indicate moderate to fresh winds around the southern periphery of the ridge east of the Lesser Antilles. Seas are in the 8-11 ft range within this area of winds based on several altimeter passes. For additional information please visit http://www.hurricanes.gov/marine $$ GR