000 AXNT20 KNHC 041103 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 603 AM EST Thu Jan 4 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...SPECIAL FEATURES... As of 04/0900 UTC, a vigorous middle to upper level trough is on water vapor imagery over the eastern Gulf of Mexico and the west N Atlc waters supporting a deepening and complex area of low pressure focused on a 972 mb low near 34N74W. A cold front extends from the low SW to 30N68W to the southern Bahamas near 22N72W through eastern Jamaica continuing to 15N80W. Gale force winds are currently in place N of the Bahamas and west of the front with seas to 18 ft. Hurricane-force winds are off the east coast of the US north of the discussion area. The complex low will continue to move N-NE offshore of the east coast of the US reaching Nova Scotia, Canada by tonight. See the latest NWS NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC and NWS OPC High Seas Forecast under AWIPS/WMO headers HSFAT1/FZNT01 KWBC for more details. A tight pressure gradient in the SW Caribbean between surface ridging in the NW basin and lower pressure associated with the aforementioned cold front and a center of low pressure off central Panama support gale force winds west of the low center. Latest scatterometer data show gale force NW to N winds from 10N to 13N west of 81W. These winds are forecast to diminish below gale force before this afternoon. However, fresh to near-gale force winds will prevail west of the front through early Friday morning. 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 04N08W to 04N20W. The Intertropical Convergence Zone axis extends from 04N20W SW to 01N30W to 01N38W. Scattered moderate convection is from 02N to 08N between 16W-34W. ...DISCUSSION... GULF OF MEXICO... A strong surface ridge prevails across the Gulf anchored by a 1030 mb high centered north of Tampico, Mexico. A tight pressure gradient east of the Sierra Madre Oriental, Mexico continue to support fresh to near gale force winds south of 27N between 83W and 98W. The ridge will weaken gradually relaxing the pressure gradient and winds will diminish into moderate breeze levels for the upcoming weekend. CARIBBEAN SEA... Southwesterly flow aloft prevails over the Caribbean basin between the base of an upper level trough over the northwestern Caribbean, and an upper level ridge anchored east of the Windward Islands. The trough aloft supports a cold front analyzed across eastern Cuba from 20N74W across eastern Jamaica to 15N80W. Ahead of the front, an elongated surface trough extends from the Windward Passage to a 1009 mb low off the coast of central Panama. This area of low pressure is underneath diffluent flow aloft, which is supporting scattered heavy showers and scattered tstms between 71W and 83W, including the Windward Passage and Hispaniola. Otherwise, the eastern Caribbean remains under fair skies within moderate to occasional fresh trades. The cold front is forecast to become stationary over Hispaniola Friday. Fresh to near gale force winds are expected W of the boundary through the upcoming weekend. ...HISPANIOLA... Scattered showers are across Hispaniola due to an elongated area of low pressure anchored by a 1009 mb low off the coast of central Panama. A cold front currently moving off E Cuba into the Windward Passage will move over Haiti tonight and then will stall there Friday before dissipating over the weekend. NE winds will increase through the Windward Passage region and persisting through early next week. ATLANTIC OCEAN... Outside of the Special Features deepening area of low pressure across the W Atlc, scattered showers and isolated tstms are across the southern Bahamas and the approaches to the Windward Passage being supported by a diffluent environment aloft. The remainder of the central and eastern Atlc is under the influence of a surface ridge anchored by a 1034 mb high centered W-SW of the Iberian peninsula near 35N14W. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos