000 AXNT20 KNHC 152250 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sun Jun 16 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 2230 UTC. ...SPECIAL FEATURES... Heavy Rainfall over Central America and Mexico: A Central American Gyre (CAG), which is a broad low to mid level cyclonic circulation centered over the Central America, continues to develop. Widespread deep convection driven by the CAG is expected this weekend through Friday June 21. Heavy rainfall with this event is expected along the Pacific coast of northern Central America and southern Mexico. This heavy rainfall may cause life- threatening flash floods and mudslides, especially in areas of hilly terrain. Heavy rainfall is also possible across Quintana Roo, Yucatán, Tabasco, and Veracruz this week. Please refer to bulletins and forecasts from your local weather forecast and emergency management offices for specific information. ...TROPICAL WAVES... A tropical wave is along 22W, from 15N southward, moving westward around 10-15 kt. No significant convection is noted with this feature. A central Atlantic tropical wave is analyzed along 55W this morning based on upper air sounding data from Cayenne, French Guiana. The wave extends from 17N southward. It is moving west at 10-15 kt. Scattered moderate convection is from 10N to 14N between 53W and 56W. A central Caribbean tropical wave that was over the southwest Caribbean lost clear definition as it was absorbed into the broad low to mid level cyclonic circulation associated with the Central American Gyre described in the Special Features sections. ...MONSOON TROUGH/ITCZ... The monsoon trough enters passes off the coast of Africa near 14N17W to 06N25W to 05N35W. The ITCZ continues from 05N35W to 06N50W. Scattered moderate convection within 60 nm either side of the ITCZ between 22W and 30W. The Central American Gyre described in the Special Features is lifting the East Pacific monsoon trough north across the western Caribbean. This monsoon trough currently extends from the coast of Colombia near 11N74W to a 1008 mb low pressure along the coast of Nicaragua to 13N83W. Numerous moderate to isolated strong convection is from 12N to 16N west of 78W. GULF OF MEXICO... Please read the SPECIAL FEATURES section for information on heavy rainfall across Quintana Roo, Yucatán, Tabasco, and Veracruz this week. A surface trough extends from the northeast Gulf of Mexico near 29N85W to low pressure in the Bay of Campeche near 1007 mb low pressure at 18N92W. Scattered moderate showers and isolated thunderstorms are noted from 25N to 28N between 85W and 90W. Gentle to moderate easterly breezes persist across the Gulf. Combined seas are 4 to 6 ft in the southeast Gulf and 2 to 4 ft elsewhere. For the forecast, the northeast portion of the aforementioned surface troughs will shift NW and dissipate through tonight. The broad low to middle level cyclonic circulation, a Central American Gyre, is centered over the south-central Gulf of Mexico and extends into Central America. This feature is expected to become better organized through Mon, as it drifts westward. 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 middle part of next week, then move west or west-northwestward. Active convection across the southeast Gulf, along with increasing winds and building seas, is expected to shift westward with this system into the middle part of next week, significantly impacting the south- central and northwest Gulf. CARIBBEAN SEA... Please read the SPECIAL FEATURES section for information on heavy rainfall across Quintana Roo and Yucatán this week. Please read the MONSOON TROUGH/ITCZ section for information on active strong convection in the W Caribbean. Moderate to fresh E to SW winds prevail over the central and western Caribbean, with 5-7 ft seas across these waters. Gentle to moderate trades are noted in the E Caribbean with 3-5 ft seas. For the forecast, the Central American Gyre will bring fresh to strong SE winds and scattered showers and thunderstorms across portions of the western and northwestern Caribbean over the next few days. Expect increasing winds and building seas over the western Caribbean, including the Gulf of Honduras, through Tue in association with the gyre. ATLANTIC OCEAN... 1016 mb low pressure centered north of the Bahamas near 29N75W, with a trough extending to Cape Canaveral, FL, and another trough extending northeast of the low out of the area. Scattered moderate convection persists within 90 nm to the southeast of this low pressure. Farther east, a trough reaches from 27N63W to near the southern Bahamas at 22N70W. Scattered moderate convection is near the northern tip of this trough, from 27N to 29N between 55W and 63W. Broad high pressure dominates the region farther east, north of 20N, centered on 1028 mb high pressure near 34N37W. This pattern is supporting gentle SE breezes and 3 to 5 ft east west of 50W, moderate E breezes and 5 to 7 ft between 25W and 50W, and fresh to strong NE winds with 6 to 8 ft seas east of 25W. For the forecast west of 55W, the trough northeast of the Bahamas will shift eastward and exit the region through early next week, with active convection continuing ahead of it. Expect fresh E winds north of 26N and west of 65W by Tue, as high pressure builds north of the area, behind the exiting trough. Low pressure is forecast to develop near 26N to the east of the Bahamas by Wed, and move west to west-northwest and into Florida through late Thu. $$ Christensen