604 AXNT20 KNHC 171138 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sun Dec 17 2023 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1030 UTC. ..SPECIAL FEATURES... Gale Warning for Gulf of Mexico, Florida Offshore and Western Atlantic: A stationary front extends westward from 21.5N60W to 23N73W, then continues as a warm front to a deepening 999 mb low in the NE Gulf of Mexico near 27.5N84.5W. To the north of the front, strong high pressures of 1030 mb is near 34N59W. A tight gradient between these features will maintain near-gale to gale NE winds along with 10 to 16 ft seas across the NE Gulf of Mexico, with SE winds of 30 to 40 kt across the Florida offshore waters. As the low tracks northeastward toward the Florida Big Bend area and deepens further, these winds and seas will shift into the northeastern Gulf of Mexico coastal waters, and expand across the offshore waters of central/northeast Florida and northwest Bahamas. This low is expected to cross northern Florida and southern Georgia today and exit into the western Atlantic late this afternoon. This will produce gale southerly winds and high seas of 15 to 23 ft to shift northward and eastward into the western Atlantic waters N of 26N and W of 73W today. Meanwhile, this will allow winds and seas across the eastern Gulf of Mexico and southeast Florida offshore waters to slowly subside. Gale Warning over the Central Atlantic: Strong high pressure shifting slowly eastward across the Bemuda area is producing a tight pressure gradient between it and a stationary front extending from 30N40W to 23.5N51W. Recent satellite scatterometer data show near-gale to gale-force NE winds north of 29N between 46.5W and 50W. Seas of 12 to 14 ft are in this area. Winds have since fallen below gale-force in recent hours. However, reinforcing high pressure across the NW Atlantic will build SE this afternoon and tonight to restrengthen the pressure gradient, and produce gale-force NE winds again tonight through Mon north of 25N and between 40W and 52W. Seas will build to 15 to 20 ft during this time. Please read the latest NWS High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more details of these events. ...MONSOON TROUGH/ITCZ... The monsoon trough exits the Africa continent near 08N12.5W to 06N16W. The ITCZ extends westward from 06N16W to 02N46W. Scattered moderate isolated strong convection from 03N to 12N between the west coast of Africa and 27W. Another area of similar convection is noted from 02N to 07N between 32W and 48W. ...GULF OF MEXICO... Please read the Special Features section above for details on the Gale Warning in effect for the E Gulf waters. A secondary cold front extends from SE Louisiana to the central Bay of Campeche. Strong NW to N winds are found behind this front, with seas of 8 to 14 ft in NE swell, as measured by buoy data and recent altimeter. A deep layered upper level low pressure is moving slowly eastward across the eastern Gulf and is supporting the gale low in the NE Gulf. Associated convection has shifted E and NE and inland. For the forecast, a 999 mb low pressure currently near 27.5N84.5W will continue to strengthen as it moves NE and into Florida near the Big Bend this morning. Northerly gales will continue W of the low across the NE Gulf through mid morning. An associated cold front will trail from the low, moving SE of the Gulf and into the NW Caribbean this morning. Strong NW to N winds will continue behind this front in the central and eastern Gulf through this evening. High pressure will then settle in over the area through early next week allowing for marine conditions to gradually improve. ...CARIBBEAN SEA... A developing frontal trough associated with the low in the Gulf of Mexico extends from western Cuba to the northern Gulf of Honduras. Fresh NW to W winds are occurring west of this front, with seas of 5 to 7 ft in NW swell. Convergent southeasterly winds east of the trough axis are triggering scattered showers and thunderstorms across central Cuba, with scattered showers between Cuba and Jamaica and the Cayman Islands. Otherwise, a 1030 mb Bermuda high is north of the area, and producing fresh trade winds across the north central and northeast Caribbean. Gentle to moderate easterly winds and 4 to 6 ft seas prevail in the south central and southeastern Caribbean. Light to gentle winds and 4 to 6 ft seas in moderate easterly swell are found elsewhere across the southwestern basin. For the forecast, strong high pressure across the western Atlantic along 34N will support fresh trade winds across the north-central and northeast basin today, before the high pressure shifts E and weakens, causing winds to gradually diminish tonight. A cold front has reached the Yucatan Channel and will move SE into the NW Caribbean this morning, stretch from eastern Cuba to Costa Rica Mon morning, then stall and weaken from central Hispaniola to Panama by early Wed. Fresh to strong NW to N winds will follow this front, becoming N to NE Tue night through Thu. ...ATLANTIC OCEAN... Please read the Special Features section about the ongoing Gale Warning and significant swell event occurring W of 70W and the central Atlantic developing gale conditions. A stationary front extends from near 21.5N60W to 23N73W, then continues as a warm front across central Florida. Strong to gale- force E to SE winds prevail N of these boundaries, where seas are 8 to 13 ft in NE swell, except higher in the area of gales. Scattered moderate to strong showers and thunderstorms spread northward from central Cuba and the Bahamas, to the W of 72W, and continue beyond 31N. 1030 mb high pressure is centered NE of Bermuda, leading to this tight pressure gradient across the region. Across the Atlantic W of 55W and south of the stationary front, fresh to locally strong E to SW winds prevail E of the Bahamas, where seas are 8 to 10 ft in NE swell. To the E, a surface trough extends from 1015 mb low pressure near 28N44W to 21N45W. Scattered showers are along the trough. Farther NE, a stationary front described in the special features sections drapes across to the N of the low. Scattered clusters of strong convection are along the front N of 29N between 33W and 42W. Gentle to moderate winds prevail across the waters S of this frontal boundary to the ITCZ, where seas are 5 to 8 ft in N to NE swell. These gentle to moderate trades extend westward into the Lesser Antilles. Seas are 6 to 9 ft in NE swell E of the islands. For the forecast, the stationary front will weaken and become ill defined today. Strong to gale-force SE winds N of this boundary N of 26N and W of 74W early this morning, including the NW Bahamas and offshore NE Florida will continue. Deepening low pressure in the NE Gulf of Mexico will move NE and into Florida soon, then move across the far NW Atlantic waters Sun afternoon and N of the area Sun night, dragging a cold front with it. SE gales will expand offshore Florida today, ahead of the low, then spread E and NE with time, ahead of the cold front. Behind the front, NW gales will also develop N of 27.5N by Sun evening. Scattered to numerous strong thunderstorms are expected ahead of the low and the cold front through Sun night. The cold front will reach 31N79W to Central Cuba by Sun evening, then extend from 31N68W to central Hispaniola by Mon evening. The front will then move slowly E into the middle of next week as high pressure builds behind it. $$ Stripling