000 AXNT20 KNHC 100908 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue Sep 10 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 0600 UTC. ...SPECIAL FEATURES... Tropical Storm Francine is centered near 24.4N 96.2W at 10/0900 UTC or 100 nm SSE of mouth of The Rio Grande, moving NNW at 4 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Peak seas are currently around 20 ft. Numerous moderate to strong convection is observed within 150 nm in the SW semicircle, and between 75 and 360 nm in the NE quadrant where the system continues to interact with a stationary front. A slow north-northwest motion is expected through this morning, followed by a turn to the northeast with an increase in forward speed. On the forecast track, Francine is anticipated to be just offshore of the coasts of northeastern Mexico and southern Texas through today, and make landfall in Louisiana on Wed. Francine will likely become a hurricane today, with significant strengthening expected before it reaches the coast. Francine is expected to bring heavy rainfall and the risk of considerable flash flooding for much of Louisiana and Mississippi through Thu. Flash and urban flooding is probable across portions of northeast Mexico and far southern Texas into early Wed, and the Mid-South Wed night into Fri morning. Swells generated by Francine are affecting portions of the coast of northeastern Mexico and southern Texas. These swells are expected to spread across the northwestern and northern Gulf of Mexico coastline during the next day or so. These swells are likely to cause life- threatening surf and rip current conditions. Please consult products from your local weather office. Please consult products from your local weather office. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Six NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Central Tropical Atlantic (AL92): An elongated 1010 mb area of low pressure over the central tropical Atlantic near 15N41W is producing some disorganized shower and thunderstorm activity. Numerous moderate convection is noted within 150 nm in the SW quadrant and between 60 nm and 150 nm in the SE quadrant. Associated winds are currently 20 to locally 25 kt with seas estimated to be up to around 8 ft. Environmental conditions appear only marginally conducive for some slight development during the next couple of days, but a tropical depression could still form during that time while the system moves westward at 5 to 10 kt over the central tropical Atlantic. The chance of tropical cyclone formation over the next 48 hours and 7 days is medium. Please refer to the latest NHC Tropical Weather Outlook at hurricanes.gov for details. ...TROPICAL WAVES... A tropical wave is in the far eastern Atlantic near 21W, from 05N to 18N, moving west at 10 to 15 kt. Scattered moderate isolated strong convection is noted from 09N to 15N between 16W and 21W. A tropical N Atlantic tropical wave is near 59W, south of 20N to Guyana, moving westward at 15 to 20 kt. Scattered showers and thunderstorms are present from 09N to 12N between 57W and 60W. A tropical wave is moving from the central to the western Caribbean near 76W, south of 20N, moving westward at around 15 kt. The wave is enhancing thunderstorm activity over SW Haiti as well as over portions of NE Colombia, but otherwise no other deep convection is noted over water. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast of Africa near 13N17W and continues WSW to a 1012 mb low pressure near 11N32.5W, then to a 1010 mb low pressure (AL92) near 15N41W, then to another 1010 mb low pressure near 13.5N50.5W. No ITCZ axis is evident in the tropical Atlantic. Scattered moderate isolated strong convection is noted from 07N to 11N between 21W and 31W. Similar convection is within 210 nm NW of the low pressure area near 11N32.5W, and between 60 nm and 150 nm in the NE quadrant of the low pressure area near 13.5N50.5W. GULF OF MEXICO... Please refer to the Special Features section for information on Tropical Storm Francine in the western Gulf of Mexico. Outside of the influence of Francine, a stubborn stationary front extends from just N of Tampa Bay, Florida to NE of Francine near 28N95W. In addition to the convection described with Francine above, some scattered showers and thunderstorms are possible across the Gulf waters mainly N of 26N and east of 90W. Gentle to moderate E to SE winds and seas of 3 ft or less are noted in the eastern Gulf E of 87W, with moderate to strong winds and 4 to 7 ft seas W of 87W outside of the influence of Francine. For the forecast, Francine will strengthen to a hurricane near 25.4N 95.6W this afternoon, move to 27.1N 94.2W Wed morning, 29.0N 92.5W Wed afternoon, move inland and weaken to a tropical storm again near 31.4N 91.1W Thu morning, and continue NE and weaken to a tropical depression near 33.8N 90.5W Thu afternoon. Associated rough to very rough seas will persist off the coast of Veracruz and Tamaulipas through at least this morning. Looking ahead, winds and seas will diminish across the Gulf Thu through Fri, however westerly swell will impact the southeastern Gulf Thu through Fri. High pressure will become established over the N-central Gulf Sat and Sat night. CARIBBEAN SEA... Please see the Tropical Waves section for information on a Tropical Wave moving from the central to the western Caribbean. Divergence aloft due to an upper level low centered between Bermuda and Puerto Rico, low-level wind convergence and abundant moisture combine to support showers and isolated thunderstorms from Puerto Rico and the Virgin Islands to the Lesser Antilles. This rain activity may result in localized flooding, especially in low-lying areas. Please consult products issued by your local weather office. Similarly, the interaction between an upper level low off western Costa Rica and the eastern Pacific monsoon trough result in scattered showers and isolated thunderstorms over the SW Caribbean, especially S of 13N and W of 77W. Generally drier conditions are noted elsewhere in the basin. A relatively weak pressure gradient across the Caribbean sustains moderate to locally fresh trades in the central Caribbean, with gentle to moderate winds elsewhere. Seas are slight to moderate across the basin, highest in the S-central waters. For the forecast, a tropical wave moving from the central to the western Caribbean from near eastern Cuba and eastern Jamaica southward will move across the remainder of the basin through the end of the week. Fresh to locally strong winds will pulse offshore eastern Honduras with moderate to fresh winds in the S-central Caribbean, and mainly gentle to moderate trades elsewhere. Slight to moderate seas will prevail across the basin. ATLANTIC OCEAN... Please see the Special Features section for details on low pressure (AL92) in the central Atlantic. A nearly stationary front extends from 31N74W to NE Florida, supporting widely scattered showers and isolated thunderstorms across the waters N of 24N and W of 68W. Fresh to strong winds are W of the front per an earlier ASCAT scatterometer pass, with seas of 5 to 8 ft. The remainder of the tropical Atlantic is under the influence of a broad subtropical ridge positioned well N of the Azores. Gentle to moderate winds are found across the majority of the waters W of 35W away from AL92, along with seas of 4 to 6 ft. Moderate to fresh winds are E of 35W, locally strong between Africa and the Canary Islands. Seas are 4 to 6 ft E of 35W, except locally to 8 ft downwind of the fresh to strong winds. Meanwhile, a trough of low pressure located several hundred nautical miles SW of the Cabo Verde Islands is expected to merge in a couple of days with a strong tropical wave, described above near 21W, located between the west coast of Africa and the Cabo Verde Islands. Environmental conditions appear favorable for gradual development of this system, and a tropical depression will likely form during the latter part of this week while the system moves west-northwestward at 10 to 15 kt. This system has a low chance of tropical cyclone formation through 48 hours, and a high change through 7 days. Please refer to the latest NHC Tropical Weather Outlook at hurricanes.gov for details. For the forecast W of 55W, a stationary front extends from 31N74W southwestward to N-central Florida. Widely scattered showers and thunderstorms are N of 24N and W of 68W. The front may make some southward progress before stalling from NW of Bermuda to near Cape Canaveral, Florida by Wed, with slightly higher winds and seas N of it. Across the remainder SW North Atlantic waters, winds should remain gentle to moderate. Mainly slight to moderate seas will prevail S of the front through the next few days. $$ Lewitsky