000 AXNT20 KNHC 292329 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 729 PM EDT Wed Mar 29 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 2315 UTC. ...SPECIAL FEATURES... As of 29/1800 UTC, a 992 mb low pressure is analyzed near 31N56W. A cold front extends from the low center to the Leeward Islands into the NE Caribbean. A band of showers with isolated thunderstorms is noted ahead of the front. The low is still producing gale force winds of 35-45 kt over the discussion area, particularly N of 28N between the cold front and 60W based on the most recent scatterometer data. The low will move N of 31N this evening and away from the forecast region tonight and Thursday. Gale force winds are still expected ahead of the front over the next 24 forecast. A that time, the front will extend from 31N43W to 23.5N50W to 16.5N62W. Please see the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 13N16W to 01N24W. The ITCZ extends from 01N24W to the coast of Brazil near 05S38W. Scattered moderate and isolated strong convection is noted S of the monsoon trough from 00N-04N between 10W-20W. A cluster of moderate to strong convection is just south of the Equator between 15W and 18W. ...DISCUSSION... GULF OF MEXICO... A ridge dominates the Gulf region anchored by a 1019 mb high pressure located near the central Bahamas. The pressure gradient between the ridge and lower pressures over eastern Mexico supports moderate to fresh SE-S winds across the Gulf west of 87W, and gentle to moderate SE winds east of 87W. A dryline is over eastern Texas followed by a cold front. This cold front will move off the Texas coast Thursday morning, and across the northern Gulf through Saturday morning with a band of scattered showers and thunderstorms. In the upper levels, an upper level trough is inland over New Mexico and Texas supporting the above mentioned cold front. An upper level ridge, with axis across Florida, dominates the Gulf of Mexico. Strong southwesterly winds aloft are transporting mid-upper level moisture across the western Gulf. CARIBBEAN SEA... Currently, the pressure gradient across the basin remains fairly weak and results in mostly gentle to moderate trades, with the exception of moderate to fresh SE winds across the western Caribbean, including also the Yucatan Channel and the Gulf of Honduras. Moderate to locally fresh NE winds are also noted per scatterometer data across the Windwrad Passage and downwind to just SE of Jamaica. Weak high pressure building north of the area will support mainly moderate to fresh winds across most of the basin, with the exception of fresh to strong winds near the coast of Colombia, and in the Gulf of Honduras at night. A weak cold front extends across the Leeward Islands into the NE Caribbean generating some shower activity. The front is forecast to drift SE and gradually dissipate across the central Lesser Antilles by Friday. Patches of low level moisture, embedded in the trade wind flow are noted across the remainder of the area. A diffluent pattern aloft is helping to induce convection over parts of Venezuela and Colombia. SW flow aloft across the eastern Caribbean is advecting some mid-to-upper level moisture from northern South America across the eastern Caribbean into the Lesser Antilles. ...HISPANIOLA... Strong upper-level subsidence and implied dry air mass is seen on water vapor imagery over Hispaniola. Shower activity will be limited over the next 24-48 hours and mainly associated with the trade wind flow. A surge of moisture is likely expected during the upcoming weekend. ATLANTIC OCEAN... Main feature in the Atlantic is the low pressure system located near 31N56W. Please, see Special Features section for details. A 1019 mb high pressure located near 26N74W dominates the Bahamas and the SW N Atlantic. The high will remain nearly stationary over the next 24 hours while weakenning. A cold front is forecast to enter the forecast area W of 65W tonigh and move across the forecast region on Thursday before stalling along 25N-26N W of 60W by Friday morning. The remainder of the Atlantic is under the infuence of a ridge. In the tropics, a surface trough extends from 08N46W to 01N47W and is generating isolated showers while moving W. For additional information please visit http://www.hurricanes.gov/marine $$ GR