668 AXNT20 KNHC 150539 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Fri Dec 15 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 0000 UTC surface analysis and satellite imagery through 0540 UTC. ...SPECIAL FEATURES... Central Atlantic Gale Warning: A 1003 mb low is located near 27.5N43.5W. Recent scatterometer data depicted southwest gale- force winds northeast of the low. While, northeast strong winds were depicted west and northwest of the low. Recent Altimeter data show that seas have begun to subside and are now 10 to 14 ft west and northwest of the low, N of 20N. In addition, satellite imagery shows a cluster of scattered moderate to isolated strong convection north of 23N between 35.5W and 41W. This activity will continue to shift north- northeastward through tonight. As it does, the tight pressure gradient producing the gales will weaken just enough to allow for the gale-force winds to drop to just below gale criteria. Seas will gradually continue to subside through Fri within the area of the low pressure system. Atlantic Significant North Swell: Large north swell due to ongoing near gale force winds associated with the low pressure system mentioned above will continues to sustain 12 to 16 ft seas from 22N to 31N between 38W and 50W. This swell will subside by Fri morning west of 41W. Seas east of 45W and north of 25N will remain elevated through late Fri night. Western Atlantic and Florida Offshore Waters Gale Warning and Significant Swell Event: A slow moving cold front extends from SE of Bermuda to the northwest Bahamas near 25N75W, where it becomes stationary and continues through the Florida Straits. Gale force winds are likely occurring over waters between the Bahamas and Florida from 25.5N to 30N. Seas within these areas of winds are 12 to 18 ft. The prevailing tight pressure gradient between strong high pressure over the eastern U.S. and lower pressures in the Gulf of Mexico and NW Caribbean will support near gale force to gale force winds offshore Florida through the weekend. Seas will build to 19 ft between 27N and 29N behind the front by Fri. Seas of 12 to 14 ft will spread southward between 60W and the north facing coasts of the Bahamas, reaching 22N by Sat morning. This front will become fully stationary and aligned along 24N by the weekend. Gulf of Mexico Gale Warning: Strong high pressure building across the eastern United States is supporting NE to E strong to near-gale force winds over the northern and eastern Gulf of Mexico as depicted by recent scatterometer pass. Easterly gales will prevail across the offshore Florida waters through Fri. Low pressure will form in the SW Gulf Fri night then move NE and into Florida Sat night. This will produce additional gales in the NE Gulf. A cold front will trail from the low, exiting the Gulf by early Sun. Strong north winds will spill into the western Gulf Sat and Sat night behind the front. High pressure will then settle in over the area through early next week allowing for marine conditions to improve. Expect widespread showers and thunderstorms over most of the central and eastern Gulf through early Sun. For more details on the Significant Swell and Gale Warnings, please read the latest High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from 07N13W to 05.5N16W. The ITCZ begins near 05.5N16W to 05N31W to 03N49W. Scattered moderate convection is noted from 02N to 08N between 13W and 41W. ...GULF OF MEXICO... Please read the SPECIAL FEATURES section for details on the Gale Warning in the NE Gulf and a forming gale force low pressure system occurring this weekend. A stationary front related to the boundary in the western Atlantic Gale force winds described in the SPECIAL FEATURES, enters the Gulf of Mexico through the Florida Straits to near 22N93W. A recent ASCAT pass depicted a large swath of strong to near gale force NE to E winds behind the boundary. Rough seas of 10 to 16 ft are also present in this area. North of 23N between 91W and 94W, fresh to strong NE to E winds with 8 to 12 ft seas are noted. A surface trough is depicted in the SW Gulf. Moderate to fresh NE winds shifting NW south of 20N surround the feature. Broken to overcast multilayered clouds along with scattered to numerous showers and areas of moderate rain are over the basin north of 23N. For the forecast, strong high pressure building across the eastern United States will support fresh to strong winds over the northern and eastern Gulf of Mexico tonight, with easterly gales offshore OF Florida through Fri. Low pressure will form in the SW Gulf Fri night then move NE and into Florida Sat night. This will produce additional gales in the NE Gulf. A cold front will trail from the low, exiting the Gulf by early Sun. Strong north winds will spill into the western Gulf Sat and Sat night behind the front. High pressure will then settle in over the area through early next week allowing for marine conditions to improve. Expect widespread showers and thunderstorms over most of the central and eastern Gulf through early Sun. ...CARIBBEAN SEA... Fresh to strong NE to E winds prevail over most of the central basin, with the strongest winds noted offshore Colombia, within the Windward Passage, south of Hispaniola, and in the NW Caribbean north of 20N. Moderate to fresh winds are noted elsewhere. Seas are up to 10 ft offshore Colombia, 8 to 10 across the central basin and 6 to 9 ft elsewhere. For the forecast, strong high pressure N of the region across the eastern U.S. will support fresh to strong trade winds across much of the basin into tonight, before they gradually diminish. A cold front will move through the Yucatan Channel and into the NW Caribbean Sat night into Sun. Fresh to strong NW winds will follow this front. ...ATLANTIC OCEAN... Please read the SPECIAL FEATURES section for details about the the ongoing Gale Warnings and the Significant North Swell. Aside from those conditions described above under SPECIAL FEATURES, an area of fresh to strong winds is noted south of 23N and west of 55.5W to the Greater Antilles, where seas are 8 to 10 ft. Elsewhere, moderate to fresh winds along with moderate seas prevail throughout the rest of the basin. For the forecast, a slow moving cold front extends from SE of Bermuda to the northwest Bahamas near 25N75W, where it becomes stationary and continues through the Florida Straits. This front will become fully stationary and aligned along 24N by the weekend. The combination of strong high pressure building north of the area and the front will result in near gale to gale force northeast to east winds and high seas over the waters W of 74W and north of 25N into Fri night, with these winds spreading north- northeastward to the north- central forecast waters Sun night through Mon night. The front will then lift N as a warm front while slowly dissipating, in advance of Gulf of Mexico low pressure that will cross Florida Sat night. This low will move through the NW Atlantic waters Sun or Sun night, when a large area of gales is likely E of the low. Widespread showers and thunderstorms are expected over most of the western half of the area through the weekend. $$ KRV