000 AXNT20 KNHC 211746 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Tue Nov 21 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: A cold front extends from 31N54W to the US Virgin Islands. Strong to gale-force N winds are present W of the front to 70W and N of 23W. Seas in these waters are 10-19 ft. Strong S winds are also noted ahead of the front to 50W, N of 24N. A low pressure is developing along the front and as the low tracks SE through Wed night, gale force winds will continue in the forecast waters through Wed afternoon along with a broad area of strong winds on both sides of the front N of 23N and E of 65W. High seas over 20 ft will accompany the strong to gale-force winds. This non-tropical low is forecast to move southeastward across the central subtropical Atlantic over warmer sea surface temperatures during the next few days, and environmental conditions appear conducive for this system to gradually acquire tropical characteristics. A subtropical or tropical storm could form by the latter part of this week, as the system continues moving eastward followed by a turn northeastward by the weekend. This system has a low chance of development in 48 hours and medium chance in 7 days. Regardless of development, northerly swell will lead to seas of 12 ft or greater N of 20N and E of 65W into late week. Gulf of Mexico Gale Warning: As of 1500 UTC, a cold front extends from Mississippi to Veracruz, Mexico. Scattered moderate to isolated strong convection is noted ahead of the front, especially north of 27N. Strong to near gale-force northerly winds are found behind the cold front, with the strongest winds occurring off Veracruz. Seas are 7-11 ft behind the front. The front is forecast to reach from the western Florida Panhandle to the Bay of Campeche tonight, with gale force winds developing off Veracruz this afternoon. Gales will continue through Wed morning. Rough to very rough seas of up to 15 ft will accompany the gale force winds. Winds and seas will subside late Wed into Thu as high pressure settles in. Please read the latest High Seas Forecast, issued by the National Hurricane Center at the website - www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and the latest Offshore Waters Forecast to the west of 55W, at www.nhc.noaa.gov/marine/offshores.php for details on both Gale Warnings. ...MONSOON TROUGH/ITCZ... The monsoon trough is draped across central Africa. The ITCZ extends from 07N27W to 07N50W. A few showers are seen near the boundary. ...GULF OF MEXICO... Please read the Special Features section about a Gale Warning in southwestern Gulf. The remainder of the Gulf of Mexico is dominated by a strong ridge over New England. Moderate to locally fresh SE-S winds are evident in the eastern Gulf, especially east of a line from Pinar del Rio, Cuba, to Alabama. Seas in these waters are 3-6 ft, with the highest seas occurring in the Florida Straits. Slight to gentle southerly winds and 2-4 ft prevail elsewhere. For the forecast, a cold front stretches from southeastern Louisiana to south of Tampico, Mexico. The front will extend from the western Florida Panhandle to the Bay of Campeche tonight, with gale force winds developing off Veracruz this afternoon through tonight with rough to very rough seas. Strong to severe thunderstorms, with locally high winds and seas, will be along and just ahead of the cold front today for areas N of 28N. Strong winds will follow the front across most of the Gulf through Wed night. The front will then move across the far SE Gulf into the eastern Bay of Campeche by Wed night. Winds and seas will subside into Thu as the front stalls across the SE Gulf and high pressure settles in. ...CARIBBEAN SEA... A weak low pressure (Invest 99L) is located in the south-central Caribbean Sea, off the Guajira peninsula of Colombia. A surface trough extends to the northeast toward the US Virgin Islands, while the eastern Pacific monsoon trough reaches the low pressure from the coast of Costa Rica. Recent satellite images show only a few weak showers near the low pressure and the surface trough. A recent scatterometer satellite pass captured fresh to strong NE winds north of the low pressure and surface trough, especially east of 73W. Seas in these waters are 4-7 ft. Invest 99L has a low chance of tropical development in the next 48 hours. For more details, please visit hurricanes.gov Moderate to locally fresh NE-E winds and seas of 3-5 ft are present in the Windward Passage and the Lee of Cuba. Elsewhere, moderate or weaker winds and slight seas prevail. For the forecast, disorganized showers and thunderstorms over the central Caribbean Sea are associated with a small area of low pressure. Nearby dry air is forecast to prevent additional significant development of the system as it begins to drift slowly westward during the next couple of days. This system has a low chance of formation in the next 48 hours and 7 days. Meanwhile, high pressure building toward the Greater Antilles will cause fresh to strong NE winds in the Windward Passage and just S of Hispaniola today through Wed afternoon. Elsewhere, winds will be moderate or less into late week. ...ATLANTIC OCEAN... Please refer to the Special Features section details on a Gale Warning. A 1037 mb high pressure system over New England extends southward into the SW North Atlantic. A dry airmass dominates the region, maintaining fairly tranquil weather conditions. The pressure gradient between the ridge and the cold front mentioned in the Special Features section sustain fresh to locally strong E-SE winds, especially west of 70W. Seas in these waters are 7-10 ft. Farther east, a dissipating stationary front stretches from 31N24W to 21N36W to 23N46W. A few showers are noted near this boundary. Moderate to fresh westerly winds and seas of 7-10 ft are evident north of the front, with the highest seas occurring near 31N46W. Moderate to locally strong southerly winds are seen on latest satellite-derived wind data east of 24W and north of 24N. Wave heights in this region are 5-8 ft. Moderate or weaker winds and moderate seas are prevalent in the remainder of the basin. For the forecast west of 55W, low pressure is developing near 35N51W with a cold front extending SW to the Anegada Passage. Gale force winds are ongoing west of the low and front. As the low tracks SE through Wed night, gale force winds will continue in the forecast waters through Wed afternoon along with a broad area of strong winds on both sides of the front N of 23N and E of 65W. High seas over 20 ft will accompany the strong to gale- force winds. As this low moves over warmer sea surface temperatures during the next few days, environmental conditions appear conducive for this system to gradually acquire tropical characteristics. A subtropical or tropical storm could form by the latter part of this week, as the system continues moving eastward followed by a turn northeastward by the weekend. This system has a low chance of development in 48 hours and medium chance in 7 days. Regardless of development, northerly swell will lead to seas of 12 ft or greater N of 20N and E of 65W into late week. Looking ahead, fresh to strong winds will develop offshore northern Florida today into tonight in advance of the next cold front that will push off the Florida coast by Wed. $$ Delgado