000 AXNT20 KNHC 032324 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Jun 4 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... At 03/2100 UTC, Tropical Depression Arlene was downgraded to a remnant low, and the last advisory was issued by the National Hurricane Center on Arlene. At this time, it is centered near 23.7N 84.7W at about 120 nm WSW of the Dry Tortugas, moving SSE or 150 degrees at 6 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained winds are 25 kt with gusts to 35 kt. Continued weakening is forecast, and Arlene is expected to dissipate on Sunday. Seas are 8 to 9 ft. Rainfall amounts of 1 to 2 inches with localized higher amounts up to 5 inches are possible into this evening across portions of the southern Florida Peninsula. The heavy rainfall could lead to isolated flash, urban, and small stream flooding impacts. Please, read the latest HIGH SEAS FORECAST issue by the National Hurricane Center at web-site https://www.nhc.noaa.gov/text/MIAHSFAT2.shmtl and the latest Arlene NHC Forecast/Advisory and Public Advisory at www.hurricnes.gov for more details. Caribbean Heavy Rainfall... A mid-upper level trough, with axis across the eastern Gulf of Mexico and the NW Caribbean, continues to support the development of showers and thunderstorms over parts of Florida, Cuba, Jamaica the Cayman Islands and Hispaniola. The southwesterly flow on the E side of the trough continues to transport abundant moisture across this area. Saturday morning, up to 6 inches of rainfall was reported across parts of eastern Cuba. A tongue of moisture is forecast to persist tonight and Sun over Hispaniola as the mid- level trough moves eastward. This could lead to more rounds of showers and thunderstorms. ONAMET, the Weather Service in Dominican Republic, has issued alerts/advisories for possible flooding of rivers, urban floods and landslides. ...TROPICAL WAVES... A tropical wave was added to the 1800 UTC map along 13W south of 11N. Scattered moderate to isolated strong convection is noted ahead of the wave axis from 03N to 08N between 13N and 19W. Tropical wave diagnostics confirmed the presence of the wave as well as the Hovmoller Diagram. A central Atlantic tropical wave is near 42W south of 12N, moving west around 15 kt. Scattered moderate convection is seen on either side of the wave axis from 08N to 11N between 32W and 40W. Parts of this convective activity could be also associated with the ITCZ. Another Atlantic tropical wave is near 57W from 12N southward, moving west at 5 to 10 kt. Isolated to scattered moderate convection is present from 08N to 11N between 54W and 57W. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic along the Guinea Bissau coast near 12N16W, then continues SW to near 08N25W. The ITCZ extends westward from 08N25W to 09N40W, then resumes from 07N43W to 08N54W. Most of the convection is associated with the above mentioned tropical waves. ...GULF OF MEXICO... Please read the Special Features section above for details on the remnant low of Arlene. As this system moves eastward, the associated moisture will affect the Straits of Florida tonight into Sunday. This may lead to another flare up in convection overnight over parts of the Straits of Florida and the far southern Florida Peninsula. Outside of the remnant low of Arlene, now located over the SE Gulf, a weak ridge dominates the western Gulf. The most recent scatterometer data indicate the cyclonic circulation associated with Arlene with mainly fresh winds within about 250 nm on the NW quadrant of the low center. Scattered showers and thunderstorms are on the E side of Arlene. Seas are 8 to 9 ft within these winds. Elsewhere, light to gentle winds are observed, increasing to gentle to moderate between Arlene and the ridge across the central Gulf waters where seas are in the 6 to 8 ft range. Seas of 1 to 3 ft prevail in the NW and NE Gulf, and also in the Bay of Campeche. For the forecast, Arlene, as a remnant low, will move to 23.6N 83.2W by Sun morning, and dissipate Sun afternoon. Fresh winds may pulse off the western coast of the Yucatan Peninsula Sun night and Mon night. Elsewhere over the Gulf, gentle to moderate winds are expected through middle of the week. ...CARIBBEAN SEA... A mid to upper level trough continues to enhance the development of showers and thunderstorms over the Greater Antilles. Please read the Special Features section at the beginning for more information on heavy rainfall over Hispaniola. The remnant low of Arlene could support some shower and thunderstorm activity over western Cuba tonight and early Sun as the system moves eastward across the Straits of Florida. Elsewhere, the Atlantic ridge extends westward into the eastern Caribbean producing moderate to locally fresh SE winds E of 70W based on satellite derived wind data with seas of 3 to 5 ft. A weak pressure gradient is noted across the central and NW Caribbean, where light to gentle southerly winds are noted. Seas are 1 to 3 ft, except 5 to 7 ft in the Yucatan Channel. For the forecast, expect fresh winds tonight near the Yucatan Channel as the remnant low of Arlene moves close to the area. Elsewhere, a weak pressure pattern will maintain gentle to moderate trades across the Caribbean and the tropical Atlantic, with occasional fresh pulses along the coast of Venezuela starting Mon night. Looking ahead, winds and seas will increase slightly over the eastern and central Caribbean by mid week, while high pressure builds northeast of the region over the Atlantic. ...ATLANTIC OCEAN... A surface trough extends from off the Georgia/South Carolina coast to near Miami into the remnant low of Arlene located over the SE Gulf of Mexico. Aided by an upper-level trough across the far eastern Gulf of Mexico, scattered showers and thunderstorms are occurring near the Florida east coast and nearby waters. Another surface trough extends southwestward from a 1003 mb low located just south of Bermuda to near 29N77W. A 180 nm wide-band of showers and thunderstorms extends from Hispaniola all the way to the NE to near 27N65W. Convergent southerly winds feeding toward these features are coupling with a diffluent pattern aloft to generate this convective activity. A frontal boundary stretches from the same low eastward along 27N50W to 28N30W to a weak 1012 mb low pres located near 33N23W. Moderate to fresh SW winds and seas 0f 6 to 8 ft are near the frontal boundary N of 26N between 50W and 65W. South of this front, a 1017 mb high pressure is analyzed near 23N26W. Mainly light to gentle winds and seas of 3 to 5 ft prevail elsewhere across the Atlantic E of 60W, with an area of gentle to moderate trades between the southern periphery of the Atlantic ridge and the ITCZ between 40W and 60W. For the forecast W of 55W, fresh to strong winds are likely near and to the SE of the low situated near Bermuda as it shifts ENE through Sun night, impacting zones mainly north of 25N and east of 65W. A cold front will move into the waters off northeast Florida by early Mon, before stalling from Bermuda to the northern Bahamas Tue, and dissipating through mid week. Fresh to locally strong NE to E winds and building seas are expected behind the front over the waters off northeast Florida Sun and Mon. $$ GR