000 AXNT20 KNHC 121020 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue Nov 12 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 0600 UTC surface analysis and satellite imagery through 1020 UTC. ...SPECIAL FEATURES... Atlantic Ocean Significant Swell: Residual large northerly swell across the central Atlantic is sustaining hazardous seas of 12 to 13 ft north of 22N between 35W and 54W. As this swell continues to decay while retreating northeastward, this will allow seas to subside further through this morning and possibly drop below 12 ft this afternoon. Please refer to the High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at websites: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more details. Excessive Rainfall Risk across Southern Central America: Persistent SW flow associated with a Central America Gyre (CAG) will continue to bring abundant tropical moisture across southern Central America. This combined with a diffluent pattern aloft will keep the potential for heavy rainfall high through at least mid- week. The most significant rainfall will affect western Costa Rica, and the southwestern corner of Panama. This information is provided by the Weather Prediction Center's International desk team. Please refer to your national weather agency for more details. ...TROPICAL WAVES... A tropical wave is in the central Caribbean with axis near 72W, moving westward at 5 to 10 kt. Enhanced by a diffluent pattern aloft, scattered moderate convection is occurring over the central Caribbean Basin, and portions of the E and SW Caribbean. There is a high chance of tropical development when this wave enters the western Caribbean after midweek. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic along the Guinea coast then reaches southwestward to 09N17W. The ITCZ continues westward from 09N17W to 04N36W, then turns northwestward to south of Barbados at 11N59W. Scattered moderate isolated strong convection is noted from 02N to 09N between 08W and 30W, and from 01N to 07N between 30W and 47W. ...GULF OF MEXICO... Broad low pressure associated with the remnats of Rafael prevails over the central basin while surface ridging gradually builds to the west and east of it. The pressure gradient between the ridge over the central United States and the low in the gulf is supporting moderate to fresh winds between 86W and 95W with moderate seas to 6 ft ongoing in the western semicircle of the low. Light to gentle winds and slight seas are elsewhere this morning. For the forecast, a weak low and trough, remnants of Rafael will meander over the central Gulf through this evening before moving to the NW basin and dissipating Wed. The pressure gradient between a strong ridge building over the eastern United States and the low will support the development of moderate to fresh E to SE winds over the eastern half of the basin tonight through Thu, reaching strong speeds in the NE Gulf and the Straits of Florida Wed and Wed night. A weak cold front will sink into the NE Gulf Thu and exit the NE basin Thu night. Mainly moderate NE to E winds and slight to moderate seas will dominate the basin the remainder forecast period. ...CARIBBEAN SEA... Please read the Special Features section at the beginning for details on the potential heavy rainfall across south Central America. A tropical wave extends from the Windward Passage to Haiti to NW Colombia and continues to generate scattered heavy showers and tstms over the central and portions of the eastern and southwest Caribbean. A low pressure meanders over the SW basin near 13N78W, which is supporting moderate SW winds across the offshore waters of Panama and Colombia. A second low pressure center is in the NW Caribbean, anchored by a 1009 mb low. A weak pressure gradient over that region supports light to gentle winds and slight seas. Over the E Caribbean and Tropical Atlantic waters, moderate trades prevail with moderate seas, except E of the Leeward Islands and the Atlantic passages where seas are rough to 11 ft due to long period northerly swell associated with a frontal boundary N of the area. For the forecast, showers and thunderstorms will continue in the central Caribbean, including Hispaniola, as a tropical wave moves across the region through today. A low pressure over the SW Caribbean will move to the offshore waters of NE Nicaragua and E Honduras Wed night into Thu and enhance NE winds in the Lee of Cuba to fresh to strong speeds. Moderate to fresh N to NE winds will spread over the remainder NW Caribbean by late Thu while moderate to fresh SW winds develop over the SW basin. The low is forecast to deepen by Fri evening, resulting in fresh to strong winds and rough seas over the NW and SW Caribbean through Sun night. There is a medium chance for this system to become a tropical depression late this week. Otherwise, large N swell associated with a stationary front NE of Puerto Rico will continue to impact the NE Caribbean Passages and the Tropical Atlantic waters through tonight. ...ATLANTIC OCEAN... A stationary front extends from 31N32W SW to 19N50W to 24N68W where it transitions to a warm front that connects to a 1010 mb low near 31N74W. A strong ridge has built to the north of this front, which continue to support moderate to fresh E to SE winds across the offshore waters E of the Bahamas as well as rough seas to 11 ft in long period N swell. Surface ridging is to the E of the front, creating a moderate pressure gradient against low pressure over NW Africa. This is sustaining moderate to fresh N to NE winds from the coast of NW Africa to about 30W where moderate seas also prevail. For the forecast west of 55W, moderate to fresh E to SE winds and rough seas will continue to affect the offshore waters E of the Bahamas as a stationary front extends from 19N50W to 24N68W. Rough seas associated with this front will gradually subside by this evening. Another cold front moving off the southeastern U.S. coast will reach from Bermuda to the central Bahamas offshore waters this evening, and from 31N55W to the Virgin Islands Wed evening, then move E of the area by Thu evening. Fresh to locally strong N to NW winds and rough seas will follow this front and affect most of the area through Thu. A third front may enter the NW offshore waters Thu night into Fri, affecting the offshore waters N of 27N with mainly moderate to fresh winds through the weekend. $$ Ramos