000 AXNT20 KNHC 280425 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 102 PM EST Sat Jan 27 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 1745 UTC. ...SPECIAL FEATURES... Atlantic and Gulf of Mexico Gale Warning: A very tight pressure gradient between a cold front extending from 30N47W to 23N61W where it stalls while it weakens to the southern Bahamas, and very strong high pressure of 1040 mb centered N of the area. This tight pressure gradient has induced a large area of near gale to minimal gale force NE to E winds over the waters between the front and the Bahamas S of about 27N. Seas are in the range of 10 to 16 ft with these winds. A gale warning prevails for the waters W of the Bahamas including the Straits of Florida and far eastern Gulf of Mexico near 83W. Fresh to strong NE to E winds are elsewhere W of the front, including through the Atlantic passages in the Bahamas. Latest model guidance indicates these winds will diminish to just below gale force on Sun morning near sunrise. Gale force winds W of the Bahamas that include the Straits of Florida and far eastern Gulf of Mexico are forecast to diminish to strong NE to E winds this evening. Please see the latest NHC High Seas Forecast under AWIPS/WMO headers Misfit/FZNT02 KNHC for more details on this event. Caribbean Gale Warning: The combination of very strong high pressure centered E of the mid-Atlantic states and lower pressure over South America is bringing minimal gale force NE to E winds near the coast of Colombia. These conditions will persist late at night into the early morning hours through Mon. Please see the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details on this event. Far E Atlantic Gale Warning: Another very strong high pressure system, this one of 1041 mb is centered NE of the Azores near 40N20W. The tight pressure gradient to its SE and S is allowing for NE gale force winds that reach to strong gale force over Meteo France marine zones of Agadir, Tarfaya and to near gale force NE winds over Canarias except for strong gale force winds over the eastern portion of that zone. NE winds are reaching near gale force at times over zone Cap Blanc. These conditions are expected through this evening. With the tight gradient not expected to slacken in the short term, the gale conditions for Agadir, Tarfaya and the near gale to gale for Canarias are forecast to continue through Sun night. Please refer to Meteo France Weather Bulletins for more information. ...MONSOON TROUGH/ITCZ... The Monsoon Trough axis extends from the coast of Africa near 06N10W to 04N14W where the ITCZ begins and then continues along 01N20W to 0N30W to 0N40W to 01S50W. Scattered moderate convection is within 210 nm either side of the axes. ...DISCUSSION... GULF OF MEXICO... Strong surface high pressure centered over the NW Atlc is supporting a large area of fresh to strong E winds E of 90W. The exception is in the far SE Gulf and Straits of Florida where strong E winds are gusting frequently to gale force. These winds are forecast to diminish early Sunday morning as strong ridging over the eastern Gulf begins to weaken. An upper level short- wave supports a 1021 mb low off the Texas coast from where a stationary front extends NE to SE Louisiana near 29N91W and then E to 29N85W. Radar data show scattered heavy showers and tstms N of 27N W of 90W associated with these features. Scattered showers and isolated thunderstorms are in the SE Gulf from 23N to 28N between 84W and 89W being supported by upper level diffluent flow. A rather progressive upper level pattern will bring surface low pressure southeastward towards the area of southeastern Louisiana or southwestern Mississippi early tonight, with a trailing cold front across the NW Gulf waters. The low is forecast to rapidly move across the NE Gulf on Sun while pushing the cold front across the eastern gulf waters through early on Mon. Expect widespread rain along with scattered showers and isolated thunderstorms with system. CARIBBEAN SEA... Please see the SPECIAL FEATURES section above for details regarding the gale conditions near the coast of Colombia. Fresh to strong NE winds prevail at the lee of Cuba. Fresh to strong trades are occurring elsewhere across the basin, except for the gale force winds near the coast of Colombia as described above under SPECIAL FEATURES. A surface trough along the eastern Yucatan Peninsula and Belize continue to support scattered showers and isolated thunderstorm over the Gulf of Honduras. Isolated showers and thunderstorms are noted over Hispaniola being supported by upper level diffluent flow. Strong to near gale force NE winds are likely to occur through the Windward Passage next week. Expect increasing low-level moisture along with scattered showers to impact the NE Caribbean and islands in that location including Puerto Rico through Sun night as a decaying frontal boundary over the central Atlantic drops southward towards the NE Caribbean and strong to near gale force NE winds advect the associated moisture and shower activity towards that section of the Caribbean. ATLANTIC OCEAN... Please see the SPECIAL FEATURES section above for details about the gale conditions over portions of the waters between the Bahamas and a central Atlantic cold front. A cold front enters the discussion area through 30N46W to 23N61W where it becomes a weakening stationary front to the southern Bahamas. Meanwhile, very strong high pressure of 1040 mb is over NW Atlc waters. The resultant tight gradient support near gale to minimal gale force winds along with large seas in the SW N Atlc S of 27W. These conditions are expected to continue into Sun morning. Scattered showers are within 175 nm E of the front N of 25N. The stationary portion of the front is forecast to continue to weaken through the weekend. The frontal remnants will drift southward towards the NE Caribbean Sea islands, most likely as a shearline. Precipitable water GFS model guidance indicates that moisture and precipitation will increase for the NE Caribbean islands through the weekend. before diminishing late Sun. Farther east, a 1041 mb high pressure system centered near 40N20W dominates the area E of the cold front maintaining rather stable weather over much of the central and eastern sections of the area, except for the far eastern portion S of 24N and E of 40W where abundant mid and upper level clouds are streaming eastward towards Africa ahead of a mid to upper level trough located N of 15N between 30W and 40W. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos