000 AXNT20 KNHC 162216 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Jun 17 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 2200 UTC. ...SPECIAL FEATURES... Heavy Rainfall over Central America and Mexico, and gale warning over the Gulf of Mexico: A broad area of low pressure is centered over northern Central America and southern Mexico. Environmental conditions over the southwesternGulf appear conducive for subsequent gradual development of the low, and a tropical depression or tropical storm could form by midweek while it moves slowly westward or west-northwestward. This weather pattern is known as a Central American Gyre (CAG), and often persists for several days. Regardless of tropical cyclone development, this weather pattern will cause life- threatening conditions that include flooding and mudslides. With the current CAG, the circulation is producing strong SW monsoonal flow in the eastern north Pacific that will advect abundant tropical moisture northward into the coastal terrain of Central America and southern Mexico. The pattern is expected to persist through at least the middle of this week across northern Central America and southern Mexico, with the threat to life and property increasing as the event persists. The main areas impacted by the heavy rainfall will be northwest Nicaragua, southwest Honduras, and coastal sections of Honduras, El Salvador, Guatemala, and the Mexican states of Chiapas and Oaxaca. Heavy rainfall is also possible across Quintana Roo, Yucatan, Tabasco, Veracruz, northeast Queretaro, northeast Hidalgo, and San Luis Potosi this week. The persistence of the moist pattern will create very hazardous conditions in the region that could be life-threatening. Please refer to your local meteorological office bulletins for more detailed information. For mariners in the Gulf of Mexico, the developing broad low pressure will also support increasing winds and building seas across the Gulf of Mexico through mid week. Expect rough seas to 8 ft starting tonight across the south- central Gulf. Seas will build further through Mon, with winds increasing to minimal gale force north of the Yucatan Peninsula early in the afternoon. ...TROPICAL WAVES... The axis of an eastern Atlantic tropical wave is near 25W, from 15N southward, moving westward around 10-15 kt. No significant convection is evident near the wave. The axis of a central Atlantic tropical wave is analyzed near 57W, extending from 16N southward. It is moving west at 10-15 kt. Scattered moderate convection is from 06N to 16N between 50W and 55W. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast of Guinea Bissau near 12N16W, then continues westward to 06N30W. The ITCZ extends from 06N30W to 05N52W. Scattered moderate convection is noted along the ITCZ between 25W and 30W, and from 40W and 48W. GULF OF MEXICO... Please read the SPECIAL FEATURES section for information on the possibility of heavy rainfall across the Yucatan Peninsula, Tabasco, Veracruz, and parts of Queretaro, Hidalgo, and San Luis Potosi this week. A Central American Gyre is currently over southern Mexico and Central America. A surface trough extends over the southwest Gulf and runs from 23N96W toward a 1006 mb low pressure located near northern Guatemala/Mexico border. The pressure gradient between a ridge across the eastern Gulf and the low supports moderate to fresh winds over the south-central Gulf, with gentle to moderate winds elsewhere. Seas are in the 4-6 ft range over the central and southeast Gulf, and 2-4 ft elsewhere. A large cluster of showers and thunderstorms are active along the west coast of the Yucatan Peninsula. Scattered showers and thunderstorms are evident elsewhere across the central Gulf. For the forecast, the gyre center is expected to persist through the middle of this week, while shifting WNW to NW into the southwest Gulf of Mexico. A broad area of low pressure is forecast to form from this system over the SW Gulf of Mexico on Monday or Tuesday. Environmental conditions appear conducive for subsequent gradual development of the low, and a tropical depression or tropical storm could form by midweek while it moves slowly W or W-NW. Heavy showers and thunderstorms across the southeast Gulf, along with increasing winds to gale-force and rough seas, are expected to shift over the W Gulf with this system Mon evening through late Wed. CARIBBEAN SEA... Please read the SPECIAL FEATURES section for information on the potential for heavy rainfall across the Yucatan Peninsula this week. A Central American Gyre is currently over southern Mexico and Central America. The circulation around the gyre is supporting strong to near-gale force SE winds over the northwest Caribbean, where combined seas are 6-8 ft. Moderate to fresh winds are noted elsewhere, with 4-6 ft seas. Numerous showers and scattered thunderstorms are active between Honduras and Jamaica. For the forecast, the gyre center is expected to persist through the middle of this week, while shifting WNW to NW into the Gulf of Mexico. The resultant pattern will continue to produce fresh to near gale-force SE winds and scattered showers and thunderstorms across the western Caribbean this evening, then shift across the Gulf of Mexico tonight through Wed. Otherwise, gentle to moderate trades over the central and eastern Caribbean will reach moderate to fresh speeds on Wed and prevail through Fri evening. ATLANTIC OCEAN... A surface trough extends from 31N60W to a weak 1015 mb low pressure located near 28N64W, then continues southward toward the Windward Passage. Scattered showers and thunderstorm are active along this trough near 26N66W. Moderate NE winds and 3 to 5 ft seas are noted west of the trough, with light breezes and 2 to 4 ft elsewhere west of 55W. The remainder of the Atlantic discussion area is dominated by 1025 mb high pressure near 34N38W. This pattern is supporting light to gentle breezes and 4-6 ft combined seas north of 20N between 35W and 55W, and moderate to fresh NE to E winds and 5-7 ft combined seas elsewhere east of 55W. For the forecast west of 55W, gentle to moderate NE to E winds will reach fresh speeds north of 25N and west of 60W by Mon morning, as high pressure builds north of the area. The low will weaken into a trough by Mon night, however, a low pressure is forecast to re-develop by midweek a few hundred miles northeast of the central Bahamas. Environmental conditions could be conducive for some development of this system thereafter while it moves westward or west-northwestward. Regardless of development, fresh to strong winds and rough seas will develop across the offshore waters north of 25N Mon night through Thu. $$ Christensen