377 AXNT20 KNHC 160551 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Sat Dec 16 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 0550 UTC. ...SPECIAL FEATURES... Gulf of Mexico, Florida and Western Atlantic Gale Warning and Significant Swell event: Strong high pressure of 1034 mb across the eastern United States, extending eastward toward Bermuda combined with a stationary front that stretches from 24N70W across the NW Bahamas and the Straits of Florida into the Gulf of Mexico supports gale force winds on either side of southern Florida, including the Straits of Florida. A buoy in the central Gulf of Mexico recently reported 18 ft. Seas 12 ft of greater are noted across the Gulf waters roughly from 23N to 29N between 83W and 93W. Similar sea heights are seen from 23.5N to 29N E of the Bahamas to about 61W. A low pressure will develop and rapid deepen in the Gulf of Mexico. This will produce additional gales in the NE Gulf and E of Florida beginning Sat. The strong low pressure is forecast to move NE Sat and inland across the Florida Big Bend and N Florida Sat night. This system will bring heavy rainfall, gale force winds, coastal flooding due to onshore flow and some threat for severe weather from Florida to the Mid- Atlantic states. Gales will diminish in the eastern Gulf of Mexico by Sun morning while persist E of Florida and N of the NW Bahamas to about 74W. In that area, the forecast calls for S winds of 30 to 45 kt and seas of 15 to 20 ft. A cold front associated with this low will exit the Gulf of Mexico by Sun morning. Gales will continue in the western Atlantic into early next week. Gale Warning over the North Central Atlantic: An area of low pressure currently located near 31.5N50W will drift southward into our waters. Recent scatterometer pass revealed that NE gale-force winds are occurring north of the low. Therefore, gale-force winds will move into the area in the next couple of hours. Seas will build between 12 and 15 ft in the warning area. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough exits the Africa continent near 06N10W and extends to 05N14W. The ITCZ extends from 05N14W to 05N31W to 05N47W. Scattered moderate convection is evident from 03N to 10N between the west coast of Africa 32W. ...GULF OF MEXICO... The big weather maker for this weekend in the Gulf of Mexico and Florida is the low pressure that will form in the SW Gulf tonight and its rapid deepening. This system will bring severe weather conditions to the region. Please read the Special Features section for more details. Gales and hazardous marine conditions are ongoing in the basin. For the forecast, strong high pressure across the eastern United States will support strong winds over the northern and eastern Gulf of Mexico into tonight, with easterly gales offshore of SW Florida. Low pressure will form in the SW Gulf tonight, then move NE Sat and inland across the Florida Big Bend Sat night. This will produce additional gales in the NE Gulf beginning Sat. Thunderstorms in association with this low will provide locally higher winds and seas Sat and Sat night. A cold front will trail from the low, moving SE of the Gulf Sun morning. Strong north winds will spill into the western and northern Gulf Sat into Sun behind the front. High pressure will then settle in over the area through early next week allowing for marine conditions to improve. ...CARIBBEAN SEA... Strong high pressure over the eastern of the United States and the western Atlantic is producing fresh to strong NE to E winds in the lee of Cuba to about 19N, and also from central Hispaniola to about 17N. Seas are in the 5 to 8 ft range within these winds, reaching 11 ft in the Yucatan Channel. Moderate to fresh trades are noted over the south-central Caribbean, including the Gulf of Venezuela. Elsewhere, gentle to moderate winds prevail. Seas are generally 4 to 7 ft in the rest of the basin. Scattered moderate convection is depicted over the NW Caribbean on the south side of a stationary front located over the SE Gulf of Mexico. Patches of low level moisture embedded in the trade wind flow are observed elsewhere producing isolated to scattered passing showers. For the forecast, strong high pressure N of the region across the middle Atlantic states will support fresh to strong trade winds across most of the basin into tonight, before the high pressure shifts E and weakens, causing winds to gradually diminish into Sat night. A cold front will move through the Yucatan Channel and into the NW Caribbean Sat night, then stretch from the Windward Passage to Costa Rica Mon. Fresh to strong NW to N winds will follow this front. ...ATLANTIC OCEAN... A Gale Warning is in effect E of south Florida. In addition, gale-force winds will develop over the North Central Atlantic. Please, see the Special Features section for more information. A cold front enters the forecast area near 31N50W, then continues SW to near 25N61W where it becomes stationary crossing the NW Bahamas and the Straits of Florida. This front is attached to a low pressure just north of our water near 31.5N50W. Strong to near gale-force NE winds are N of the stationary front to about 29N. Seas are 12 to 15 ft in association with these winds just E of the Bahamas. These winds are advecting abundant tropical moisture over Florida producing intermittent locally heavy showers. As the low pressure forecast to develop over the Gulf of Mexico and approaches Florida, showers will become widespread across South Florida and periods of heavy rain will be possible especially heading into Saturday afternoon and Saturday night. A second cold front extends from 31N37W to 19.5N44W. This front is attached to an occluded low located N of area. The low pressure has weakened enough to allow winds in its vicinity to drop below gale force, but it is still generating an area of 12 to 13 ft over the waters N of 27N between 35W and 39W. Seas are forecast to subside below 12 ft by Sat morning. At this time, seas of 12 to 15 ft in NW swell are expected in the wake of the aforementioned cold front, covering the waters E of 55W and N of a line from 31N44W to 27N55W. Another 1010 mb weak low pressure near 30.5N40.5W is attached to this occluded front. A deep layer trough over the eastern central Atlantic is producing showers east of 30W. The remainder of the Atlantic is under the influence of a ridge. For the forecast, the aforementioned cold front over the eastern Atlanti will drift southward tonight before becoming fully stationary along 23N by Sat. The pressure gradient between the strong high pressure building north of the area and the front will result in near gale to gale-force NE to E winds and high seas over the waters W of 65W and north of 23N through tonight. The front will then gradually dissipate Sat night through Sun, in advance of Gulf of Mexico low pressure that will move NE across Florida Sat night. This low will move through the NW Atlantic waters Sun, when a large area of southerly gales will develop SE of the low. Numerous thunderstorms in association with this low will provide locally higher winds and seas this weekend. $$ KRV