000 AXNT20 KNHC 211647 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sat Sep 21 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 1630 UTC. ...SPECIAL FEATURES... Potential Heavy Rainfall in Central America: A Central American Gyre (CAG) is forecast to gradually develop over Central America through this weekend, near Costa Rica and Panama. It will slowly drift NW across Nicaragua, Honduras, and the Yucatan Peninsula through the middle of next week. Aided by abundant tropical moisture, this system may produce significant rainfall near Panama through this weekend, then Costa Rica and eastern Nicaragua late on Sunday through early next week. Afterward, heavy rain may spread over central and northern Guatemala and western Honduras during the first half of next week, and into Belize and the Yucatan Peninsula late next week. This will lead to an increased potential for life- threatening flash flooding and mudslides in these areas. It is recommended that residents in the aforementioned areas stay alert on the latest information from their local meteorological agencies. Please refer to the Tropical Weather Discussion for the Eastern Pacific at website: https://www.hurricanes.gov/text/MIATWDEP.shtml for rainfall across El Salvador and the Pacific coasts of Nicaragua, Guatemala, and southern Mexico. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic along the border of Senegal and Guinea-Bissau near 13N16W, then extends to 08N35W. The ITCZ extends from 08N35W to 10N51W. Scattered moderate convection is from 08N to 12N east of 20W. GULF OF MEXICO... Light to gentle easterly winds and slight seas prevail across the Gulf of Mexico, due to high pressure centered over the SE United States. For the forecast, high pressure will dominate into early next week. A broad area of low pressure is likely to form by the early to middle part of next week over the northwestern Caribbean Sea and the adjacent portions of Central America. Thereafter, gradual development of this system is possible, and a tropical depression could form as the system moves slowly to the north or northwest over the northwestern Caribbean Sea and across the Gulf of Mexico through the end of next week. There is a medium chance of tropical cyclone formation in the next seven days. Regardless of development, winds and seas will start increasing across the SE Gulf early next week. CARIBBEAN SEA... Please refer to the SPECIAL FEATURES section above for potential heavy rainfall and already increasing convection associated with a developing Central American Gyre (CAG). Gentle to moderate trades with seas of 3-5 ft prevail across the Caribbean Sea. Scattered moderate convection is in the western Caribbean, from 12N to 18N between 77W and 84W, and in the central Caribbean from 12N to 16N between 73W and 75W. For the forecast, moderate to fresh winds and moderate seas are expected across the E and central Caribbean tonight. A broad area of low pressure is likely to form by the early to middle part of next week over the northwestern Caribbean Sea and the adjacent portions of Central America. Thereafter, gradual development of this system is possible, and a tropical depression could form as the system moves slowly to the north or northwest over the northwestern Caribbean Sea and across the Gulf of Mexico through the end of next week. There is a medium chance of tropical cyclone formation in the next seven days. ATLANTIC OCEAN... A surface trough enters the W Atlantic near 31N73W and extends across the central Bahamas to central Cuba near 23N78W. Scattered moderate convection is from 25N to 31N between 68W and 72W ahead of the trough. Scatterometer data this morning depicts light winds near the trough. 1008 mb low pressure (AL96) is centered near 26N55W, and producing scattered moderate convection within 150 nm NE of the center. Winds in this region are near fresh speeds. Environmental conditions do not appear conducive for significant development of this system during the next couple of days while it drifts slowly northwestward and then northward over the central or western subtropical Atlantic. 1005 mb low pressure (Remnants of Gordon) is centered near 26N42W. Fresh to strong winds and 6-9 ft seas are within 180 nm of the center of the low pressure, mainly confined to the eastern and northern semicircles. No significant convection is noted at this time. Significant development of this system is not expected while it moves slowly northwestward over the central subtropical Atlantic during the next couple of days. 1014 mb high pressure is centered near 13N50W, and another 1014 mb high pressure is centered near 30N66W. Scattered showers are noted across the Lesser Antilles. Light to gentle winds and seas of 4-6 ft prevail across open waters. For the forecast W of 55W, a weak cold front will move off the SE coast of the US tonight and slowly move across the waters N of 25N into Mon night. $$ Mahoney