635 AXNT20 KNHC 090415 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Fri Dec 9 2022 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 0415 UTC. ...SPECIAL FEATURES... Central Atlantic Storm Warning: A non-tropical low pressure area with a central pressure of 977 mb is located about 1000 nautical miles east of Bermuda near 31N45W. An extensive area of scattered moderate convection is observed north of 18N, between 24W and 55W. Storm force winds remain in the NW quadrant of the low, embedded in a very large area of gale force winds within 300 nm west of the low and 500 nm east of the low. Very rough to high seas cover an extensive area north of 16N, between 24W and 55W. Conditions will gradually improve through Fri in the subtropical Atlantic as the low moves NE. However, seas will remain very rough north of 25N through the weekend. Large long- period north to northeast swell will impact the Atlantic waters and Caribbean Passages between the southeastern Bahamas and the E Caribbean producing high seas into the start of next week, with large E swell reaching the Florida offshore waters N of 26N early Fri through Sat. More information about this system, including the associated Storm Warning, can be found in the High Seas Forecasts issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea near 10N14W to 06N16W. The ITCZ continues from 06N16W to 04N37W. A surface trough extends from 10N42W to 04N43W. Scattered moderate convection is observed from the equator to 12N, between 30W and 50W. GULF OF MEXICO... A 1022 mb surface high is centered over SE Louisiana supporting generally fair weather conditions and mainly gentle to moderate easterly winds over the basin. Seas remain 3 to 5 ft over the majority of the basin, with 1 to 3 ft seas in the NE basin. For the forecast, high pressure near SE Louisiana will meander in the vicinity of the NE Gulf through the upcoming weekend. The ridge will shift eastward early next week as a cold front approaches the NW Gulf. Gentle to moderate winds will prevail through the weekend, increasing to moderate to fresh early next week. Winds may increase to strong as seas build up to 8 ft late Tue in the NW Gulf as the aforementioned front approaches from the NW. CARIBBEAN SEA... The pressure gradient between subtropical high pressure in the western Atlantic and lower pressure over Colombia is generating moderate to fresh NE winds west of 70W in Caribbean Sea, including the Windward Passage, where seas are in the 6 to 7 ft range. In the E Caribbean, gentle to moderate N winds prevail with mainly 4-6 ft seas. Seas are 8 to 10 ft near and SW of Atlantic passages due to long period NE swell originating from the storm force low in the central Atlantic. For the forecast, the intense low pressure system in the central Atlantic is gradually lifting northeastward away from the area through the weekend. Large NE swell across the central Atlantic will move through the Caribbean Passages and Tropical Atlantic waters through late Sat. The current weather pattern will sustain NE-E winds across much of the forecast waters. Fresh to strong pulsing NE-E winds will occur in offshore Colombia into early next week. Moderate to fresh NE winds, occasionally pulsing to strong speeds, will affect the Caribbean Passages and the lees of the Greater Antilles into Sat. ATLANTIC OCEAN... Please read the Special Features section above for details on a storm force low pressure system, affecting the waters north of 16N between 25W and 55W. Elsewhere, a weak high pressure ridge off NE Florida is supporting gentle winds and 4-6 ft seas in the far western Atlantic. In the far eastern Atlantic, weak high pressure prevails offshore W Africa, causing gentle to moderate anticyclonic flow. For the forecast W of 55W, the intense low pressure system over the subtropical Atlantic is forecast to accelerate tonight and Fri into the north Atlantic and strengthen into a powerful non- tropical cyclone. Large long-period north to northeast swell will impact the Atlantic waters and Caribbean Passages between the southeastern Bahamas and the E Caribbean producing high seas into the start of next week, with large E swell reaching the Florida offshore waters N of 26N Fri through Sat. $$ Flynn