000 AXNT20 KNHC 201710 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Fri Sep 20 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 1700 UTC. ...SPECIAL FEATURES... Potential Heavy Rainfall in Central America: Recent satellite imagery shows numerous moderate to strong thunderstorms, associated with a developing Central American Gyre (CAG), over the far southwest Caribbean impacting inland portions of Honduras, Nicaragua, Costa Rica, Panama, and Colombia. This thunderstorm and heavy rainfall activity is expected to persist through this weekend and into the middle of next week while moving northwestward, becoming focused in El Salvador, Guatemala, and southern Mexico by late next week. The heaviest rainfall is expected along the south and west coasts of Mexico, Guatemala, El Salvador, Nicaragua, and Costa Rica. Heavy rainfall will lead to 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 meteorological agencies. Please refer to the Tropical Weather Discussion for the Eastern Pacific at website: https://www.hurricanes.gov/text/MIATWDEP.shtml for more details on rainfall across the Pacific coastal areas of these nations. ...TROPICAL WAVES... A western Caribbean tropical wave has its axis near 88W, from 20N southward along the Yucatan coast and in the western Gulf of Honduras, then extending S across Central America. It is moving W at 10 kt. Scattered moderate convection is observed near the northern portion of the wave axis, generally from 16N to 20N between 81W and the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the basin from the west coast of Africa near 11N16W and continues westward to near 07N38W. The ITCZ then stretches from 07N38W to near 09N45W. Scattered moderate convection is seen south of these features between the African coast and 40W, and north of 04N. The East Pacific monsoon trough also extends across the southwest Caribbean to inland Colombia. Convection in this area is associated with a developing Central American Gyre, see the SPECIAL FEATURES section above for more details. ...GULF OF MEXICO... A diurnal surface trough is analyzed from the Bay of Campeche to just north of the Yucatan Peninsula, with scattered showers developing along and near the northern portion of the trough axis. Another surface trough is noted over the NE Gulf with no notable convection nearby. Otherwise, high pressure of 1012 mb centered near 28N93W is dominating Gulf weather, bringing dry conditions, light to gentle winds, and seas of less than 3 ft. For the forecast, moderate to locally fresh winds may pulse in the eastern Bay of Campeche nightly through the next several days. Looking ahead, a broad area of low pressure could form by the early to middle part of next week over the northwestern Caribbean Sea. 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 into the southern 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 details on convection in the southwest Caribbean associated with a developing Central American Gyre (CAG). Convergent surface winds are leading to the development of scattered showers and isolated thunderstorms in the far eastern Caribbean. Otherwise, moderate to locally fresh easterly winds and seas at 3 to 5 ft are evident in the central basin. Gentle to moderate SE to E winds and 2 to 4 ft seas are seen across the remainder of the basin. For the forecast, moderate to fresh winds and moderate seas are expected across the E and central Caribbean through at least Sat. Looking ahead, a broad area of low pressure could form by the early to middle part of next week over the northwestern Caribbean Sea. 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 into the southern 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 that extends roughly along the Gulf Stream offshore Florida is inducing scattered moderate convection in its immediate vicinity. An upper-level trough is also helping to generate areas of scattered moderate convection over and to the northeast of the Bahamas and the Turks and Caicos Islands. A 1006 mb area of low pressure centered near 25N55W and a surface trough extending both to the west and east of the low are generating scattered moderate convection along and within 200 nm of the trough axis. To the north of these features, recent scatterometer data indicated moderate to fresh E winds generally north of 26N between 50W and 59W, along with seas of 7 to 10 ft in this area. Environmental conditions appear marginally conducive for some tropical development of this system while it meanders in the Subtropical Atlantic through early next week, and there is a low chance of tropical formation over the next 7 days. To the east, another low pressure of 1007 mb, is associated with the remnants of Gordon. This low is centered near 27N43W. Convection associated with this low is mainly displaced E of the center, N of 24N between 30W and 41W. In and near this zone of scattered moderate convection, fresh to locally strong E winds and seas of 7 to 10 ft prevail. Some development of these remnants is possible over the next day or two as the low moves N or NNE. Thereafter, conditions are forecast to be less conducive for development. Elsewhere, light to gentle winds and seas at 4 to 7 ft dominate most of the basin. For the forecast W of 55W, an area of low pressure is centered near 25N55W. Fresh to strong winds and rough seas will impact the waters N of 25N and E of 60W today in association with this low. Environmental conditions appear marginally conducive for some tropical development of this system while it meanders in the Subtropical Atlantic through early next week. Otherwise, a weak cold front will move off the SE coast of the US today and slowly move across the waters N of 25N through Mon. $$ Adams