000 AXNT20 KNHC 192300 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0015 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 1800 UTC surface analysis and satellite imagery through 2230 UTC. ..MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near 03N10E and extends to 04N02W. The ITCZ continues from 04N02W to 05N14W to 00N50W. Scattered moderate convection is observed from 03N to 06N between 28W and 45W. ...GULF OF MEXICO... A cold front extends from just N of Tampa Bay to just south of Tampico, Mexico. A surface trough extends just offshore the Mexican coast from S of Tampico Mexico to the central Bay of Campeche. No significant convection is noted in association with these features. Mainly moderate NE to N winds encompass the basin on both sides of the cold front. Seas are 2 to 5 ft, highest in the western Gulf. For the forecast, the aforementioned cold front will progress southeastward tonight before weakening on Fri across the southern Gulf then dissipating across the Yucatan Channel on Sat. Fresh N to NE winds will occur along and behind of the front tonight. A reinforcing cold front will enter the northern Gulf of Mexico Fri evening and progress southward through the weekend before dissipating over the southeastern Gulf Sun. Fresh to locally strong N winds and a modest increase in seas will occur behind this front Fri night in the northern Gulf. Moderate NE winds will then prevail across the basin on Sat. Looking ahead, high pressure building across the basin behind this second front 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 through that extends from Belize eastward just offshore the Honduras coast is inducing scattered moderate convection. 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 fresh E to NE winds from the southwestern through eastern Caribbean, with locally strong ENE winds off the coast of Colombia and in the Gulf of Venezuela. Gentle to 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. Long period northerly swell is entering the NE Caribbean through Atlantic passages, leading to localized seas of 8 to 9 ft. For the forecast, fresh trade winds will continue across the eastern, central and southwestern Caribbean, as well as 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 tonight. High pressure building over the Gulf of Mexico Fri through this weekend will lead to generally moderate to locally fresh E to NE winds across the basin through the weekend, except for N to NE winds across northwest portions. Looking ahead, the high pressure will shift slowly eastward and into the western Atlantic early next week to promote fresh to locally strong NE to E winds across much of the Caribbean. ...ATLANTIC OCEAN... Fresh easterly tradewinds dominate waters S of 25N, with some strong easterly winds from 20N to 25N between 50W and 60W resulting from the pressure gradient between high pressure N of the area and the lower pressure of the tropics. A mixture of wind waves and slowly decaying northerly swell is leading to widespread seas of 5 to 8 in the tradewind belt, with a zone of 8 to 11 ft seas in the region of strong easterlies as well as Atlantic waters approaching the Antilles W of 50W. A 1016 mb low pressure center near 31N40W is inducing gales N of the area, with a trailing stationary front along 40W to about 24N. Scattered moderate convection is noted ahead of the front to about 30W, where strong SE winds are also occurring. Seas of 8 to 11 ft area associated with this system and extend eastward to the Canary Islands. Very rough seas, peaking near 14 ft are being generated by the gales to the north, and are impacting waters N of 29N between 40W and 45W. To the west, a surface trough, ahead of a cold front west of the area, extends southward to the NW Bahamas. Scattered moderate convection is noted within about 60 nm either side of this trough axis. For the forecast W of 55W, a broad fetch of fresh NE to E winds will continue tonight 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 11 ft will occur through early tonight from 18N to 24N east of 68W. Rough seas north of 15N this evening 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 diminish to moderate speeds on Fri. A cold front will stall off the coast of the southeastern United States tonight, then enter the NW zones off of Florida on Fri, and reach from 31N68W to western Cuba by Sat morning, then weaken from 31N59W to near the Windward Passage Sun morning. Fresh to strong W 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 Sun night through early next week as strong high pressure builds across the region behind the weakening front. $$ Konarik