000 AXNT20 KNHC 280607 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Sat Aug 28 2021 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 0430 UTC. ...SPECIAL FEATURES... Hurricane Ida is centered near 23.0N 84.0W at 28/0300 UTC or 90 nm W of Havana, Cuba and moving NW at 13 kt. Estimated minimum central pressure is 989 mb. Maximum sustained wind speed is 70 kt with gusts to 85 kt. The maximum sea heights are 17 ft. Scattered moderate to isolated strong convection is found mainly NW and N of the center from 22N to 25N between 83W and 86W, including N coast of W Cuba. Ida has entered into the SE Gulf of Mexico and will continue on a NW track with a slight increase in forward speed across the central Gulf on Sat night and then into the N Gulf on Sun morning. On Sun night, Isa is expected to turn toward the N and slow down while approach the US Louisiana and Mississippi coastline. Strengthening, possibly rapid, is expected, and Ida is forecast to become a major hurricane by Sat evening as it moves into the central Gulf. Ida is forecast to be a major Category 4 hurricane at landfall along the northern Gulf coast Sun. A dangerous storm surge is forecast for portions of the Louisiana, Mississippi and Alabama coasts. Rainfall of 10 to 20 inches are possible across SE Louisiana, and 4 to 10 inches across SW Louisiana, central and S Mississippi and SW Alabama. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for more details. Refer to the NHC High Seas Forecasts at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for marine impacts. A 1008 mb low pressure about 660 mb E of the Lesser Antilles is found near 14N49W. Numerous moderate to strong convection is flaring up from 13N to 16N between 47W and 49W. Additional development of this system is expected, and a tropical depression is likely to form Sat or Sat night before it moves into a less favorable environment. The disturbance is forecast to move west- northwestward through tonight, then turn northward on Sat. This system has a high chance of tropical cyclone formation during the next 48 hours. Please refer to the NHC Tropical Weather Outlook at www.hurricanes.gov for more details. An elongated 1014 mb low pressure is centered east of Bermuda near 34N52W. Disorganized scattered moderate convection is noted from 30N to 34N between 50W and 54W. Environmental conditions are expected to be marginally conducive for development. However, a tropical depression could still form by early next week. The system is expected to drift eastward through Sat, then accelerate northeastward Sun toward the central north Atlantic. This system has a medium chance of tropical cyclone formation during the next 48 hours. Please refer to the NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... An Atlantic tropical wave is along 31W from 18N southward and moving W at 15 to 20 kt. Scattered moderate to isolated strong convection is seen from 05N to 09N between 29W and 38W. Another Atlantic tropical wave is near 50W from 18N southward and moving W near 15 kt. This wave is in close proximity with the 1008 mb low pressure mentioned in the Special Features section above, and the significant convection is related to the low. A Caribbean tropical wave is along 68W from 20N southward across the E coast of Hispaniola to N Venezuela, and moving W near 15 kt. Scattered moderate convection is present over central and N Venezuela. ...MONSOON TROUGH/ITCZ... A monsoon trough passes through the coast of Mauritania near 19N16W to 11N25W to 06N38W. The ITCZ then continues from 06N38W to 06N47W, and from 12N52W to 10N60W just N of Venezuela-Guyana border. Scattered moderate to isolated strong convection is occurring near and S of the monsoon trough along the African coast from 13N to 20N between 14W and 18W. Similar conditions are also present along and up to 100 nm N of the W portion of the ITCZ. Scattered moderate convection is found near the E portion of the ITCZ from 04N to 07N between 44W and 48W. ...GULF OF MEXICO... See Special Features section above for information on Hurricane Ida, which is forecast to become a major hurricane over the central Gulf on Sat night; before making landfall as a Category 4 Hurricane along the Louisiana-Mississippi coastline on Sun. A surface trough extends southward from near Lake Charles, Louisiana to the S central Gulf. Aided by an upper-level low over the NW Gulf near 25N93W, scattered moderate convection is noted N of 24N between 89W and 94W. Gentle to moderate ENE to E trades and seas of 3 to 5 ft are evident across central and NE Gulf. Light to gentle E to ESE winds and seas at 1 to 3 ft prevail for the rest of the Gulf. For the forecast, Hurricane Ida near 23.0N 84.0W 989 mb at 11 PM EDT or 0300 UTC is moving NW at 13 kt. Maximum sustained winds are 70 kt gusts 85 kt. Ida will move to 24.4N 85.6W Sat morning, 26.1N 87.7W Sat evening, 27.8N 89.6W Sun morning, along the Louisiana coast near 29.2N 90.8W Sun evening, move inland and weaken to a tropical storm near 30.7N 91.0W Mon morning, and farther inland over central Mississippi near 32.3N 90.6W Mon evening. Ida will weaken to a tropical depression while moving inland over 34.9N 88.2W by late Tue. Light to gentle variable winds are expected in the SW gulf and far western basin through Mon. Otherwise, moderate to locally fresh return flow will establish across the basin Tue and Wed. ...CARIBBEAN SEA... Convergent fresh to strong SE to S winds feeding toward Hurricane Ida over the SE Gulf of Mexico are triggering scattered showers and isolated thunderstorms across W and central Cuba, and just N of Jamaica. Seas across the N central and NW Caribbean Basin are in the range of 6 to 9 ft, including the Yucatan Channel. Please see the Special Features section above for more information on Ida. Outside of the influence of Ida, dry conditions along with gentle to moderate trades and seas at 4 to 5 ft prevail across much of the basin. The exception is light to gentle winds and seas at 1 to 3 ft along the W edge of the basin. For the forecast, Hurricane Ida has entered into the SE Gulf of Mexico and its influence over the Caribbean Basin will steadily decrease throughout Saturday. Weather and sea conditions across the NW basin should gradually improve through Saturday evening. Moderate to fresh winds are expected elsewhere through the forecast period, except for locally strong winds in the south- central Caribbean through the weekend. Otherwise, fresh to strong winds will pulse at night in the Gulf of Honduras Sun to Tue. ...ATLANTIC OCEAN... Please see Special Features sections above for information on two low pressures that have the potential for tropical development, east of the Lesser Antilles and east of Bermuda, respectively. Convergent E to ESE winds well NE of Hurricane Ida is triggering scattered showers and isolated thunderstorms near the E Georgia- Florida coast and the NW Bahamas. An upper-level trough SE of Bermuda near 31N60W is coupling with a surface trough in the vicinity to trigger scattered showers and a few thunderstorms N of 30N between 57W and 68W. For additional convection, refer to the Tropical Waves and Monsoon Trough/ITCZ section. A surface ridge curves westward from a 1021 mb Azores high near 31N23W to NE of the Georgia coast. Light to gentle winds and seas at 4 to 5 ft are found N of 22n between 22W and 70W. Gentle to moderate ESE to SE winds and seas at 5 to 6 ft are found N of 22N between 70W and the Georgia-Florida coast. Moderate to fresh trades and seas of 5 to 7 ft are present from 10N to 22N between 45W and the Lesser Antilles, and also near the Canary Islands N of 18N between the NW African coast and 22W. Moderate to fresh SE winds and seas at 6 to 8 ft exist from the Equator to 06N between 35W and the S American coast. Light to gentle winds and seas of 4 to 6 ft prevail elsewhere across the Atlantic Basin. For the forecast west of 65W, surface ridging will extend southward into the SW N Atlantic through Sun night supporting gentle to moderate E to SE winds. A weak pressure gradient will prevail through the remainder of the forecast period, which will result in light to gentle variable winds. Otherwise, fresh to locally strong winds are expected to pulse N of Hispaniola during the evening hours through Sat night. $$ Chan