000 AXNT20 KNHC 280426 CCA TWDAT Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 704 PM EST Sat Jan 27 2018 Corrected First Special Features paragraph 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 2345 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: A very tight pressure gradient exists between a cold front extending from 32N44W to 24N51W to 22N60W, where it becomes a dissipating stationary front to the NW coast of Haiti, and strong high pressure of 1038 mb centered N of the area near 37N66W. This continues to produce a large area of near gale to minimal gale force NE to E winds over the waters N of the front to 24N and between 60W and 75W. Given the long duration of these winds, the resultant seas have build to the range of 12 to 18 ft within the area of these winds. These conditions are forecast to continue through early Sun, at which time the gradient should slacken enough to allow for the winds to diminish to strong category, however seas are forecast to remain quite high in the 13 to 15 ft range. The previous gale warning for the waters W of the Bahamas including the Straits of Florida and far eastern Gulf of Mexico near 83W was allowed to expire this afternoon. E winds over those waters have diminished to the strong to near gale force range. 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. Please see the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/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 and into the early morning hours through Tue, and possibly well into next week. 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: Strong high pressure system, this one of 1040 mb is centered NE of the Azores near 41N20W. The tight pressure gradient to its SE is forecast to maintain NE gale force winds to reach minimal to strong gale force over Meteo France marine zone of Canarias through Sun night before diminishing to strong winds on Sun. Under same tight gradient, minimal gale force NE winds are expected to continue over marine Madeira through Mon 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 the recent gale force E winds have diminished to the strong to near gale force category as of the afternoon hours. These winds will diminish further on Sun as strong ridging over the eastern Gulf begins to weaken. An upper level short-wave supports a 1019 mb low off the Texas coast near 28N95W from where a stationary front extends northeastward to SE Louisiana near 30N89W. Another stationary front extends from the low to inland the S Texas coast near Brownsville. Latest radar displays reveal scattered showers and thunderstorms with frequent lightning along and within 90 nm of the Texas coast, and N of 26N between 87W and 90W. Scattered showers and isolated thunderstorms are over 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 32N44W to 24N51W to 22N60W, where it becomes a dissipating stationary front to the NW coast of Haiti. Meanwhile, strong high pressure of 1038 mb is located well N of the area at 37N66W. The resultant tight gradient support near gale to minimal gale force winds along with large seas in the SW N Atlc from the front N to 24N and between 60W and 75W. These conditions are expected to continue into Sun morning before diminishing to strong winds. Areas of rain and scattered showers are within 120 nm E of the front N of 28N, and within 90 nm E of the front from 26N to 28N. The stationary portion of the front is forecast to dissipate through Sun. 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 E, a 1040 mb high pressure system centered near 41N20W 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 16N and E of 31W where abundant mid and upper level clouds are streaming eastward towards Africa ahead of a mid to upper level trough located N of 10N between 30W and 40W. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre