000 AXNT20 KNHC 071703 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1203 PM EST SAT JAN 7 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 1630 UTC. ...SPECIAL FEATURES... A cold front is currently analyzed across NW portions of the SW North Atlc...the northern Florida peninsula...and Gulf of Mexico from 32N79W to near Tampa Bay to 22N90W to 18N94W. The front continues moving eastward and will clear the Gulf of Mexico by Saturday night late and remain impacting the SW North Atlc waters through the remainder of the weekend into Monday. Near gale to gale force northerly winds are occurring generally S of 26N W of 94W with strong to near gale force winds occurring elsewhere W of the front. Near gale to gale force W-SW winds are forecast to materialize by this afternoon N of 30N within 150 nm E of the front in the SW North Atlc. See 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 05N09W to 05N14W to 02N24W. The Intertropical Convergence Zone axis extends from 02N24W to the Equator near 27W. Scattered moderate convection is S of 05N between 16W-35W. ...DISCUSSION... GULF OF MEXICO... The main impact across the basin this afternoon is the Special Features cold front that extends from near Tampa Bay into the SW Gulf to 20N94W to 18N94W. A pre-frontal surface trough axis is analyzed from the front near 23N88W SW to the coast of southern Mexico near 18N93W. The front continues to be supported aloft by a middle to upper level trough noted on water vapor imagery with axis extending over the Ohio River valley SW to over the lower Mississippi River valley. Scattered showers and tstms are occurring in association with the front generally within 120 nm either side of the boundary E of 87W. Scattered showers and isolated tstms are elsewhere within 120 nm E of the front. Aside from the near gale to gale force northerly winds occurring across western portions of the basin...strong high pressure anchored by a 1041 mb high centered in the Rio Grande river valley near 28N100W will continue to slide eastward to the mid-Atlc coast by Sunday night. As this occurs...the current wind field of strong to near gale winds will gradually diminish from west to east Sunday night into Monday as SE return flow re-establishes itself across the NW Gulf. CARIBBEAN SEA... Water vapor imagery continues to indicate strong subsidence over the entire basin with the exception of scattered high level cloudiness mainly over SW portions. In addition...a fairly weak pressure gradient is noted across the basin with moderate to fresh trades expected to persist through the evening and overnight hours. Slightly stronger trades...fresh to occasional strong...are expected within close proximity to the coast of Colombia and NW Venezuela. By Saturday night late...a cold front is forecast to move into the NW Caribbean resulting in strong to near gale N-NE winds that will spread southeastward to 73W by Monday morning. ...HISPANIOLA... Conditions remain fair with mostly sunny skies this afternoon. Dry air and strong subsidence aloft are providing an overall stable environment that is expected to persist the next several days keeping overall conditions tranquil across the island. ATLANTIC OCEAN... Southwesterly flow aloft prevails over the SW North Atlc region as a middle to upper level trough approaches from the west... currently with axis extending from over the Ohio River valley southwestward to over the lower Mississippi River valley. The troughing supports a 1006 mb low centered off the coast of South Carolina near 32N78W and the associated cold front analyzed SW to near Jacksonville Florida then into the SE Gulf of Mexico. Scattered showers and tstms are occurring N of 28N between 69W- 79W...and from 25N-31N between 79W-83W...including a large portion of the Florida peninsula. Strong to gale force SW winds are expected through the evening and overnight hours E of frontal passage. As the front passes...winds will shift northerly ranging from strong to near gale strength. This N-NE wind field will quickly move southeastward across the region through Monday as strong high pressure anchors to the north across the mid-Atlc coast. Otherwise...for the remainder of the afternoon and evening...a ridge axis extends from the central Atlc near 30N53W W-SW to central Cuba near 22N79W. Farther east...the same ridge continues to influence much of the central Atlc anchored by a 1029 mb high centered near 33N45W. Finally...across the eastern Atlc...a 1006 mb low is centered near 30N26W with a surface trough axis extending S-SW to 27N26W to 24N29W. This low is supported aloft by a broad cut-off middle to upper level low centered near 29N26W. Widely scattered showers and isolated tstms are occurring generally east of the surface low from 25N-38N between 16W-26W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN