000 AXNT20 KNHC 082315 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Fri Jun 9 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURES... Excessive Rainfall possible for Cuba and Bahamas: Moist southerly mid-level flow combined with enhanced rising air motion due to a strong upper-level jet positioned just northwest of this area will maintain the potential for heavy rain and strong thunderstorms. Over 4 inches (100 mm) of rain was observed over isolated areas in eastern Cuba in the last 24 hours, and additional rain is forecast over the next 2 or 3 days. The heaviest rainfall is expected to occur through Sat afternoon across portions of eastern and central Cuba and the central Bahamas. These rains could cause flooding, especially over mountainous areas in eastern and central Cuba. Please see the latest forecast from your national meteorological service for more information. ...TROPICAL WAVES... Three tropical waves are analyzed between the W coast of Africa and the Lesser Antilles. A new tropical wave is added to the 1800 UTC surface map along 12W from 12N southward based on the Tropical Wave Diagnostic and the Hovmoller Diagram, that shows the westward propagation of the wave. Scattered moderate convection is near the southern end of the wave axis. Another tropical wave is along 35W, from 13N southward, moving westward at 10 to 15 knots. Scattered moderate and isolated strong convection is noted ahead of the wave axis from 04N to 09N between 35W and 40W. A third tropical wave is along 56W, from 12N to inland Suriname, moving westward at 10 to 15 knots. Scattered moderate convection is seen where the wave meets the ITCZ from 07N to 09N between 54W and 59N. Clusters of moderate to isolated strong convection are inland on either side on the wave affecting parts of French Guiana, Suriname and Guyana. The axis of a Caribbean Sea tropical wave is near 73W, from 13N southward, moving westward at 10 to 15 knots. The wave is enhancing scattered to numerous moderate to strong convection over northern Colombia and regional waters. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of The Gambia near 13N17W the continues SW to near 08N19W. The ITCZ extends from 08N19W to 07N40W to 09N60W. Outside of the convection associated with the tropical waves, scattered moderate to isolated strong convection is noted from 05N to 08N between 20W and 26W. ...GULF OF MEXICO... A weak pressure pattern continues to dominate the Gulf waters supporting mainly light to gentle winds and slight seas. A 1012 mb high pressure is over the western Gulf near 25N95W while a surface trough extends from northern Florida to near 25N86W. Scattered showers and thunderstorms are noted over the north Gulf, particularly N of 27N between 86W and 94W. A mid- upper level trough, that now extends over the eastern Gulf, is enhancing convection over Florida and western Cuba. For the forecast, the weak pressure gradient will generally prevail across the basin through the end of the week, with mainly gentle to moderate winds. Moderate to locally fresh return flow will develop across the western Gulf over the upcoming weekend. ...CARIBBEAN SEA... See Special Feature above for heavy rainfall to affect Cuba through Sat afternoon. Convection has flared-up over western Cuba this afternoon ahead of a mid-upper level trough located over the eastern Gulf of Mexico. Scattered to numerous showers and thunderstorms continue to affect eastern Cuba and Jamaica. Similar convective activity is noted over parts of Central America, more concentrated over Panama and Costa Rica. The pressure gradient between high pressure building northeast of the area and the Colombian/Panamanian low is supporting mainly moderate to fresh E to SE winds across most of the east and central Caribbean with seas of 4-7 ft based on altimeter data. Light to gentle winds and seas of 2-4 ft are noted over the NW and SW Caribbean. For the forecast, high pressure over the central Atlantic will maintain fresh to strong easterly trade winds in the eastern and central Caribbean through Fri. The ridge will weaken Fri night through the weekend, with winds and seas across the basin diminishing modestly. A return to a more typical easterly trade wind regime is expected early next week, with locally strong trades in the south-central Caribbean and Gulf of Honduras. ...ATLANTIC OCEAN... Please see Special Features above for heavy rainfall to affect the Bahamas through Sat afternoon. High pressure of 1021 mb located over the central Atlantic near 26N55W extends a ridge westward across the Greater Antilles, the Bahamas and the western Atlantic. Multilayer clouds, with embedded showers and thunderstorms dominate most of the waters W of 70W, and N of 22N between 60W-70W. This cloudiness is associated with strong upper-level winds. Moderate to locally fresh southerly winds are noted on the western periphery of the ridge, with seas of 4-6 ft E of the Bahamas. A weakening cold front enters the forecast waters near 31N37W and extends SW to near 26N44W. A weak low pressure of 1015 mb is still noted near 23N29W. A weak pressure gradient dominates the eastern Atlantic. Light to gentle winds are blowing across the Atlantic N of 12N and E of 50W with seas generally in the 2-4 ft range. Moderate to locally fresh trades are E of the Lesser Antilles to 50W with seas of 4-5 ft. For the forecast west of 55W, a tightening pressure gradient between the high pressure system over the central Atlantic and lower pressures off the SE United States will sustain fresh to strong SW winds across parts of the SW Atlantic, mainly through Fri night. The high pressure will weaken over the upcoming weekend, resulting in a decrease in winds and seas across the area. $$ GR