000 AXNT20 KNHC 191739 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1815 UTC Thu Dec 19 2024 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 1800 UTC. ..MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near 03N10E and extends to 04N03W. The ITCZ continues from 04N03W to 05.5N13.5W to 00N51W. Scattered moderate convection is observed from 03N to 06N between 26W and 47W. ...GULF OF MEXICO... At 1200 UTC, a cold front was analyzed from the Florida Big Bend region to the NE coast of Mexico near 24N98W, with a surface trough paralleling the Mexican coast to the south of the front and a pre-frontal trough extending from 24N84W to 22N87W. No significant convection is noted in association with these features. Moderate to fresh N winds are occurring along and behind the front in the northern Gulf. Moderate NE winds are occurring in the central through southwestern Gulf of Mexico, with gentle winds noted elsewhere. Seas are generally 2 to 4 ft across the basin. For the forecast, the aforementioned cold front extending from the Florida Big Bend to NE Mexico near La Pesca will progress southeastward today before weakening on Fri then dissipating across the southern Gulf on Sat. Fresh N to NE winds will occur along and behind the front this morning. Otherwise, moderate to locally fresh N to NE winds will prevail over the basin today. Another strong cold front will enter the northern Gulf of Mexico Fri night and progress southward through the weekend before dissipating over the southeastern Gulf late Sun. Fresh to locally strong N winds and a modest increase seas will occur along and behind this front Fri night in the northern Gulf. Moderate NE winds will then prevail across the basin on Sat. Looking ahead, building high pressure will shift slowly eastward across the eastern United States late Sat through Mon, leading to moderate NE to E winds across most of the Gulf of Mexico into early next week. ...CARIBBEAN SEA... A surface trough extends from Belize eastward and southeastward to near 15N83W, paralleling the coasts of Honduras and Nicaragua. Scattered moderate convection is occurring in the vicinity of the trough. The eastern extension of the East Pacific monsoon trough also extends across the SW Caribbean, and is supporting scattered moderate convection near the coasts of Nicaragua and Costa Rica. A tight pressure gradient between these features and high pressure in the central Atlantic is supporting moderate to fresh E to NE winds from the southwestern through eastern Caribbean, with locally strong ENE winds off the coast of Colombia. Moderate NE winds are occurring in the northwestern basin. Moderate seas are noted across much of the basin, with the exception of the NW Caribbean where seas of 2 to 4 ft are noted. Locally rough seas of 8 to 9 ft prevail in areas of strong winds. For the forecast, fresh trade winds will continue across the eastern, central and southwestern Caribbean as well as through the Atlantic Passages through Fri morning as a strong pressure gradient between high pressure in the north central Atlantic and the Colombian low prevails. Winds will pulse to strong speeds offshore of Colombia and Venezuela tonight. Elsewhere, gentle to moderate NE winds are expected in the northwestern basin today. High pressure building over the Gulf of Mexico this weekend will lead to generally moderate to locally fresh E to NE winds across the basin through the weekend. Looking ahead, high pressure behind a cold front moving off the southeastern United States will promote fresh to locally strong NE winds across much of the Caribbean early next week. ...ATLANTIC OCEAN... A 1038 mb high is centered north of the area near 42N29W, and ridging dominates much of the basin. A strong pressure gradient between this ridge and lower pressure in the south-central Caribbean supports widespread fresh E to NE winds north of 15N. Strong E winds are occurring from 21N to 27N between 45W and 60W. Rough seas are noted in the aforementioned areas, and locally very rough seas to 13 ft prevail in areas of strong winds. South of 15N, moderate to fresh E winds and seas of 6 to 8 ft dominate. A strengthening low pressure system is centered near 31N38W and a cold front extends southwestward to 23N39W, with a stationary front continuing to 19N42W. Fresh to strong winds and locally very rough seas to 13 ft are wrapping along the northern and western periphery of the system. Scattered moderate to isolated strong convection is occurring from 24N to 31N between 30W and 40W. Gale-force wind gusts are likely with the strongest convection. Elsewhere, scattered showers and isolated thunderstorms are occurring east of the Bahamas and near the Turks and Caicos Islands. For the forecast W of 55W, a broad fetch of fresh to locally strong NE to E winds will continue today for areas north of 15N and between the SE Bahamas and 55W, as a tight pressure gradient prevails between high pressure in the north-central Atlantic and the Colombian low. Very rough seas to 12 ft will occur through this afternoon from 18N to 24N east of 68W with strongest winds. Rough seas north of 15N today will begin to slowly subside from north to south late tonight through early Sat. South of 15N, moderate to locally fresh trades and rough seas will prevail today before winds diminish to moderate speeds on Fri. A cold front will move off the coast of the southeastern United States late tonight and stall, then enter the NW zones off of Florida on Fri, and reach from 31N68W to western Cuba by Sat morning, then weaken from 31N60W to near the Windward Passage Sun morning. Fresh to strong N to NW winds will occur behind the front N of 28N. Looking ahead, widespread fresh to locally strong NE winds and rough seas will redevelop across areas north of 20N early next week as strong high pressure builds across the region behind the weakening front. $$ Adams