Tropical Weather Discussion
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636 AXNT20 KNHC 142335 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sat Jun 15 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURES... Heavy Rainfall over the southeastern Gulf of Mexico, southern Florida, and the northwest and central Bahamas: A low pressure is centered off the southeast US coast near 35N74W (Invest AL90). A surface trough follows the low, analyzed from central Florida to the Yucatan Peninsula. The trough is advecting ample deep tropical moisture across the southeastern Gulf of Mexico, southern Florida, the Bahamas and northward. Aided by a broad mid to upper- level trough that just northwest of the surface trough, scattered heavy showers and strong thunderstorms will continue for these locations through this weekend. Anticipate dangerous cloud to surface lightning, strong gusty winds, rough seas and low visibility. Mariners transiting these regions should exercise caution. Please refer to bulletins and forecasts from your local weather forecast offices for specific local information. Heavy Rainfall over Central America and Mexico: A Central American Gyre (CAG) continues to develop. Sporadic convection capable of producing heavy showers are already occurring in the region. As the CAG develops further, more widespread deep convection is expected to develop this weekend through next Friday, June 21. Combined with persistent moist onshore flow in the Pacific coast of Chiapas State of Mexico, Guatemala, Honduras, El Salvador and northwestern Nicaragua, very significant rainfall amounts are expected. With the soil already saturated in this area, life-threatening flash flood and mudslide are probable, especially in hilly terrains. Please refer to bulletins and forecasts from your local weather forecast and emergency management offices for specific information. Heavy Rainfall across Costa Rica and Panama: The same CAG mentioned above will also produce sporadic deep convection across Costa Rica and Panama through Saturday. Periodic heavy downpours can increase the chance of flash flood and mudslide in hilly terrain, and flooding in low lying areas. Please refer to your local weather forecast offices for more information. ...TROPICAL WAVES... A central Atlantic tropical wave is near 43W from 16N southward, and moving westward near 15 kt. No significant convection is present as it is moving through a dry and stable environment. A central Caribbean tropical wave is near 71W from 15N southward to northwestern Venezuela and eastern Colombia, and moving westward near 15 kt. Scattered showers and isolated thunderstorms are occurring over western Venezuela and eastern Colombia. This wave is expected to become absorbed into the CAG discussed in the Special Features section this weekend. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic near 14N17W to 07N21W. An ITCZ continues from 07N21W through 06N53W. Scattered moderate convection is noted near and south of the trough from 02N to 13N and E of 25W, and along the ITCZ, but in less coverage. Convergent winds near the eastern end of the East Pacific monsoon trough is triggering scattered heavy showers and strong thunderstorms across the Caribbean waters near Nicaragua, Costa Rica and Panama. ...GULF OF MEXICO... Please read the Special Features section above for information about the ongoing heavy rainfall and hazardous marine conditions across the southeastern Gulf and near southern Florida. Aside from ht features and convection described in the section above, surface ridging prevails across the remainder of the basin. Scattered showers and isolated thunderstorms are present at the central Bay of Campeche and north of the Yucatan Peninsula. Gentle to moderate S to SE winds and seas of 1 to 3 ft are noted at the eastern Bay of Campeche, the southeastern and east-central Gulf. Gentle to moderate N to NE winds and 2 to 4 ft seas prevail for the rest of the Gulf. For the forecast, the trough extending from central Florida to off the northwest corner of the Yucatan Peninsula will dissipate overnight. Farther south, a Central American Gyre will develop over the next couple of days. Environmental conditions appear conducive for a tropical cyclone to develop from this broad area of low pressure, and a tropical depression could form over the southwestern Gulf during the early or middle part of next week. Active convection, along with increasing winds and building seas are expected with this system in the early to mid part of next week, mainly impacting the south-central and northwest Gulf. ...CARIBBEAN SEA... Please read the Special Features section above for heavy rainfall across Costa Rica and Panama. Convergent moist southerly winds are coupling with divergent winds aloft to produce scattered moderate convection over the northwestern basin. Moderate to fresh E to ESE winds and seas at 6 to 8 ft are evident at the south-central basin. Gentle E to SE winds and 3 to 5 ft seas are seen at the eastern and southwestern basin. Moderate to fresh ESE to SSE winds with seas of 5 to 7 ft prevail elsewhere within the Caribbean Sea. For the forecast, scattered showers and thunderstorms are possible across portions of the western and northwestern Caribbean over the next few days as a Central American Gyre develops. Expect increasing winds and building seas over the western Caribbean, including the Gulf of Honduras, over the upcoming weekend as the gyre develops. ...ATLANTIC OCEAN... Please read the Special Features section above for information about the ongoing heavy rainfall and hazardous marine conditions for waters near southeastern Florida, and the Bahamas. Besides the surface trough and inclement weather mentioned in the section above, a broad Atlantic ridge extends southwestward from a 1031 mb high at the north-central Atlantic to near the Lesser Antilles. This feature is supporting gentle to moderate E to SE winds and seas at 4 to 6 ft north of 20N between 35W and the Florida/Georgia coast, except moderate to fresh S to SW winds and seas of 5 to 7 ft north of 28N between 71W and 76W. Near the Canary and Cabo Verde Islands, moderate to strong NNE to NE winds and seas at 7 to 9 ft dominate north of 13N between the Africa coast and 35W. For the tropical Atlantic from the Equator to 20N between 30W and the Lesser Antilles, gentle to moderate with locally fresh NE to ESE winds and seas 4 to 7 ft are noted. Gentle to moderate monsoonal and southerly winds with 4 to 6 ft seas in mixed moderate swell prevail for the remainder of the Atlantic Basin. For the forecast west of 55W, scattered to numerous showers and thunderstorms persist east of a trough reaching from roughly 31N77W to near Daytona Beach, Florida. Gusty winds, higher seas and frequent lightning will be possible with this convective activity. Fresh to strong southerly winds are expected over the western Atlantic ahead of this system through tonight. The trough will shift to the east of the region through early next week. Looking ahead, expect fresh E winds west of 70W by late Tue as high pressure builds north of the area. $$ ERA