000 AXNT20 KNHC 301030 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Mon Sep 30 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 1000 UTC. ...SPECIAL FEATURES... Tropical Depression Joyce is centered near 22.1N 49.7W at 30/0900 UTC or 790 nm ENE of the Northern Leeward Islands, moving W at 2 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Seas 12 ft or greater are occurring within 90 NM in the NE quadrant and within 60 NM in the NW quadrant with peak seas near 13 ft. Scattered moderate convection is within about 90 nm in the NE quadrant of center. Similar convective activity is noted from 23N to 27N between 44W and 50W. On the forecast track, a turn toward the northwest and north is expected during the next day or so. Joyce is likely to become a post-tropical remnant low later today and dissipate by Wednesday. 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 Joyce NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Depression Twelve is centered near 14.0N 34.1W at 30/0900 UTC or 600 nm W of the Cabo Verde Islands, moving W at 7 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Peak seas are near 10 ft. Numerous moderate to scattered strong convection is noted from 10N to 15N between 31W and 36W. Scattered moderate to isolated strong convection is seen elsewhere from 09N to 15N between 30W and 42W. Satellite derived wind data indicate fresh to strong winds of 25 to 30 kt within 120 nm NE and 75 nm SE quadrants of center. The depression is moving toward the west, and a general westward to west- northwestward motion is expected to continue through Tuesday. A gradual turn to the northwest is forecast by Wednesday. Steady strengthening is forecast, and the depression is likely to become a hurricane by Tuesday night or Wednesday. 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 Twelve NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical is along 21W/22W or a few hundred miles south-southeast of the Cabo Verde Islands. Scattered moderate convection can be found from 08N to 14N between 20W and 26W. Upper-level winds are forecast to become more conducive for gradual development of this system during the next few days, and a tropical depression could form during the middle or latter part of this week while it moves slowly westward or west-northwestward over the eastern tropical Atlantic. There is a low chance of tropical cyclone formation in the next 48 hours, and a medium chance in the next seven days. A tropical wave in the western Caribbean with axis along 82W. A broad area of low pressure is along the wave axis near 15N. This system is producing disorganized showers and thunderstorms mainly from 11N to 15N between 78W and 82W. Environmental conditions appear to be conducive for gradual development, and a tropical depression could form around the middle part of this week while the disturbance moves slowly west- northwestward. This system is then expected to move northwestward into the Gulf of Mexico during the latter portion of this week. Interests in the northwestern Caribbean Sea and along the U.S. Gulf Coast should monitor the progress of this system. There is a medium chance of tropical formation in the next seven days. Please, refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coastal plains of Guinea near 10N14W and extends to near 12N30W, then continues W of T.D. Twelve from 11N38W to 12N50W. Most of the convective activity is associated with the tropical wave and the tropical cyclone previously mentioned. GULF OF MEXICO... Please refer to the Tropical Waves section for information pertaining to potential tropical development in the Caribbean Sea and Gulf of Mexico this week. A weak ridge dominates the Gulf waters producing light to gentle winds and slight seas. Gentle to moderate E winds are noted in the SE Gulf, particularly S of 24N E of 87W, including the Straits of Florida, and in the Yucatan Channel. Moderate to fresh NW to N winds and seas of 3 to 4 ft are over the western Bay of Campeche where scattered showers and thunderstorms are observed. For the forecast, moderate to fresh northerly winds are expected near Veracruz through Tue night, then winds are forecast to increase to fresh to strong speeds Wed trough Fri night as a low pressure moves into the Gulf of Mexico during the latter portion of this week. Elsewhere, gentle to moderate winds and slight to moderate seas will prevail trough Fri. CARIBBEAN SEA... Please refer to the Tropical Waves section for information pertaining to potential tropical development in the Caribbean Sea and Gulf of Mexico this week. An upper-level low spinning just S of Hispaniola is helping to induce scattered to numerous showers and thunderstorms over the central Caribbean, more concentrated over northern Colombia, western Venezuela a,d the ABC Islands. Low-topped trade wind showers are noted over the eastern Caribbean. A weak pressure gradient dominates the basin supporting light to gentle winds, with the exception of gentle to moderate NE to E winds over the NW Caribbean. Seas are generally 2 to 4 ft. For the forecast, away from potential tropical development in the NW Caribbean, gentle to moderate winds and slight to moderate seas will persist across central and eastern portions of the basin through midweek. ATLANTIC OCEAN... Please refer to the Special Features section for information on Tropical Depression Joyce forecast to become a remnant low later today, and Tropical Depression Twelve, that is near Tropical Storm strength, and it is expected to become a large and powerful hurricane later this week. Outside of T.D. Joyce and T.D. Twelve, a 1015 mb high pressure dominates the western Atlantic, including the Bahamas and the Greater Antilles. A 1021 mb high pressure located mid-way between the Madeira and the Azores Islands extends a ridge across the eastern Atlantic, mainly N of 20N and E of 40W. The pressure gradient between this system and T.D. Twelve is generating an area of fresh to strong E winds from 15N to 20N between 29W and 35W based on scatterometer data. Similar wind speeds from the SE are seen E of T.D. Joyce from 21N to 24N to about 42W. Elsewhere E of 50W, gentle to moderate anticyclonic flow is noted. Light to gentle winds are W of 50W. Seas are generally 3 to 5 ft W of 55W and E of the Bahamas, and 5 to 8 ft elsewhere outside of the tropical cyclones. For the forecast W of 55W, weak high pressure will dominate the forecast area. Under the influence of this system mainly gentle to moderate winds and slight to moderate seas will prevail through mid week. NE swell to 8 ft will briefly impact the NE waters today. T.D. Twelve currently located over the eastern Atlantic could become a hurricane by Tuesday night or Wednesday. Seas generated by this tropical cyclone may reach the eastern forecast waters Thu night into Fri. $$ GR