000 AXNT20 KNHC 100556 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Sat Jun 10 2023 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 0000 UTC surface analysis and satellite imagery through 0500 UTC. ...SPECIAL FEATURES... Excessive Rainfall in Cuba and the Bahamas: A deep upper-level trough is over the eastern Gulf of Mexico and northeastern Florida. Strong divergent SW flow south and east of the trough axis is transporting a large amount of moisture northward from the deep tropics, creating an atmospheric river over Cuba and the Bahamas. Together with convergent southerly winds at the surface, sporadic heavy showers and strong thunderstorms are flaring up over Cuba and the Bahamas. Over the past 24 to 48 hours, Las Mercedes in Granma, Cuba reported up to 14 inches (360 mm) of rainfall. Earlier reports show 24-hour rainfall amounts ranging from 8-12 inches (200-300 mm) elsewhere in Granma, Santiago de Cuba, and Camaguey where life-threatening flooding has been reported. In the Bahamas, 8 inches (200 mm) was reported on Exuma and 4 inches (100 mm) was reported on Long Island over the past 24 to 48 hours. Additional rainfall of 4-6 inches (100-150 mm) are possible over the next 24 hours. Heavy rainfall may cause flooding and mudslides, especially in the mountainous areas of eastern and central Cuba. Conditions are forecast to improve late Sat. Please refer to the latest forecast from your national meteorological service for more information. ...TROPICAL WAVES... An eastern Atlantic tropical wave is near 20W from 13N southward, and moving west around 10 kt. Scattered moderate convection is noted from 03N to 06N between 16W and 21W. A central Atlantic tropical wave is near 42W from 13N southward, and moving west around 10 kt. Widely scattered moderate convection is present from 06N to 10N between 40W and 43W. A Caribbean tropical wave is near 63W from 12N southward into eastern Venezuela, and moving westward at 10 to 15 kt. Scattered showers and isolated thunderstorms are occurring over eastern Venezuela. Another tropical wave is near 81W from 13N southward across Panama into the Pacific, and moving at 10 to 15 kt. Isolated thunderstorms are found in the Caribbean waters adjacent Panama. ...MONSOON TROUGH/ITCZ... A monsoon trough passes through the coast of Guinea-Bissau near Bissau then continues southwestward to 06N22W. Scattered moderate convection is present from 02N to 06N between 10W and 16W. An ITCZ continues from 06N22W across 04N30W to 04N39W, then from 05N43W to just east of Amapa State, Brazil at 03N50W. Scattered moderate convection is evident up to 120 nm along either side of the first ITCZ segment, and up to 60 nm along either side of the second ITCZ segment. ...GULF OF MEXICO... A modest 1011 mb high over the northwestern Gulf of Mexico continues to dominate the entire Gulf. Light to gentle winds and seas of 1 to 2 ft exist at the north-central and eastern Gulf, including the Florida Straits. Gentle to moderate ENE to SE to S winds with 1 to 3 ft seas prevail for the rest of the Gulf. For the forecast, a weak pressure gradient will generally prevail across the basin through Sat morning with light to gentle winds. A weak low pressure along a frontal boundary will develop over Texas on Sat, resulting in moderate to locally fresh return flow over the western Gulf Sat night through Tue. By the middle of next week, the area of fresh southerly winds could expand over the eastern Gulf. ...CARIBBEAN SEA... Please read the Special Features section for information about Excessive Rainfall for Cuba. Due to the reasoning mentioned in the Special Features section, scattered heavy showers and thunderstorms are seen near Jamaica and eastern Cuba. Gentle to moderate with locally fresh E to SE trades and seas of 4 to 6 ft are present at the central and eastern basin. Mainly gentle E to SE winds with 2 to 4 ft seas prevail elsewhere in the basin. For the forecast, the pressure gradient between the central Atlantic high pressure and lower pressure over northern Colombia will maintain fresh to strong winds in the south-central basin over the next few days. Meanwhile, moderate to fresh E to SE trade winds will prevail across the eastern and central basin through the weekend. Easterly trade winds will increase to between fresh and locally strong across the Gulf of Honduras early next week. Based on the same reasoning in the Special Features section, heavy showers and strong thunderstorms will continue between eastern Cuba and Jamaica through Sat morning. ...ATLANTIC OCEAN... Please read the Special Features section for information about Excessive Rainfall for the Bahamas. A surface trough is triggering scattered showers and isolated thunderstorms off central Florida. A stationary front curves westward from west of Bermuda across 31N73W to beyond 31N77W. Scattered showers and isolated thunderstorms are evident north of 29N between 75W and the Georgia-northern Florida coast. Convergent southwesterly winds southeast of the front are producing similar conditions southwest of Bermuda north of 26N between 66W and 71W. At the central Atlantic, two surface troughs are generating widely scattered showers north of 19N between 29W and 42W. Refer to the Monsoon Trough/ITCZ and Tropical Waves sections for additional weather in the Atlantic Basin. Moderate to fresh with locally strong SW winds and 6 to 8 ft seas dominate east of the stationary front north of 28N between 64W and 75W. Gentle to moderate S to SW winds and seas of 4 to 6 ft are seen farther west from the Bahamas northward between 75W and the Florida-Georgia coast. Light to gentle winds and seas at 3 to 5 ft are evident north of 19N between the northwest Africa coast and 64W. To the south, light to gentle NNE to NE trades and 3 to 5 ft seas exist from 07N to 19N between the central Africa coast and 45W. Farther west, gentle to moderate ENE to E trades and seas of 4 to 6 ft are found from the Equator to 19N between 45W and the Lesser Antilles. Light to gentle monsoonal and southerly winds and 4 to 6 ft seas in southerly swell prevail for the remainder of the Atlantic Basin. For the forecast west of 55W, high pressure extending from the central Atlantic is creating a tight pressure gradient with low pressure off the southeast US coast. This will maintain fresh to strong SW winds over the SW Atlantic, in between the Bahamas and Bermuda, through Sat morning. As the low pressure off the southeast US coast weakens, gentle to moderate winds will prevail over the area Sat afternoon through the weekend and into early next week. Strong thunderstorms will continue over portions of the western Atlantic, including the Bahamas, through Sat morning. $$ Forecaster Chan