000 AXNT20 KNHC 030005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Fri Sep 03 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... Hurricane Larry is centered near 13.7N 35.8W at 02/2100 UTC or or about 665 nm west of the southernmost Cabo Verde Islands, moving west or 280 at 16 kt. The estimated minimum pressure is 985 mb. The maximum sustained wind speed speed is 70 kt with gusts to 85 knots. Satellite imagery shows tightly coiled bands around the center of Larry. These bands consist of numerous moderate to strong convection within 90 nm of the center, except within 60 nm in the NW quadrant. Similar convection is embedded within a wide band from 10N to 13N between 37W-40W. Scattered moderate to isolated strong convection is separated from the central dense overcast region of Larry within 30 nm of a line from 13N39W to 15N40W to 17N40W. Larry is forecast to make a gradual turn towards the west-northwest with a decrease in forward speed is expected over the next few days. A turn to the northwest is then expected by early next week. Significant to possibly rapid intensification is forecast during the next couple of days, and Larry is expected to become a major hurricane tomorrow night. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website- https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Larry NHC Forecast/Advisory and Public Advisory at www.hurricnes.gov for more details. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 21W from 02N to 19N, with low pressure of 1009 mb centered on the wave near 13N21W. This system is moving westward at 10-15 kt. Satellite imagery shows scattered moderate to isolated strong convection within 90 nm west of the low. Scattered moderate convection is within 60 nm of 14N24W. This activity continues to show signs of organization. Some limited development of this system could occur tonight and on Fri as the low moves generally westward at 10-15 kt. After that time, conditions are expected to become less conducive for development. Interests in the Cabo Verde Islands should monitor the progress of this system. A tropical wave has its axis along 57W south of 20N to inland South America, moving westward at 10-15 kt. Scattered moderate to isolated strong convection is within 120 nm east of the wave from 08N to 12N and within 60 nm west of the wave from 10N to 13N. A central Caribbean tropical wave has its axis along 76W south of 15N, moving westward near 15 kt. This tropical wave is rather ill-defined and model guidance is presently not detecting any signals with this wave. Only small isolated showers are seen within 60-90 nm either side of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough axis passes through the coastal plains of Senegal near 16N17W to low pressure of 1009 mb near 13N21W and to 13N26W. It is interrupted by Hurricane Larry. It then resumes to the SW of Larry at 11N40W to 08N49W and to 06N56W. Scattered moderate convection is within 60 nm north of the trough between 51W-55W. Otherwise, observed convection is related to Hurricane Larry, and the tropical waves. GULF OF MEXICO... A stationary front is just inland the northern Gulf coast from southwestern Georgia to Alabama, Mississippi, and into the northern half of Louisiana. Weak high pressure is present over the area. Scattered showers and isolated thunderstorms are over some areas of the northern Gulf. Similar activity is along and within 60 nm offshore the coast of Mexico from 21N to 24N. For the forecast, the stationary front will begin to gradually move south as a cold front and stall over far northeast Gulf through Fri. This pattern will maintain light to gentle breezes over most of the Gulf, with slight seas, except for fresh winds expected to pulse northwest of the Yucatan Peninsula at night through Sat. Looking ahead, an area of low pressure that is currently located near the coast of Nicaragua could move over the southwestern Gulf of Mexico during the weekend and early next week, but by then strong upper-level winds would likely limit significant development. CARIBBEAN SEA... A small 1010 mb low pressure system is centered over eastern Honduras near 14N85W. This low is along the eastern segment of the eastern Pacific monsoon trough that extends from 15N92W to the low and southeastward to coast of Colombia near 10N75W. Disorganized scattered moderate convection is seen northeast of this low from 15N to 19N between 81W-85W, including northeastern Honduras. A portion of the low's circulation could move over the Gulf of Honduras on Friday. However, development there, if any, is expected to be slow to occur. This system could then move over the southwestern Gulf of Mexico during the weekend, but by then unfavorable upper-level winds are likely to limit significant development early next week while the system moves northwestward or northward over the western Gulf of Mexico. Regardless of development, heavy rains are possible across portions of Central America and the Yucatan Peninsula through the weekend. Scattered showers and isolated thunderstorms are present from 19N to 20N between 80W-85W. Recent altimeter data passes indicate that seas are in the 3-4 ft range, except for slightly higher seas of 4-6 ft in the Gulf of Honduras. As for the forecast, a ridge north of the Caribbean Sea combined with lower pressure over northern Colombia will support moderate to fresh trade winds over the south-central Caribbean through Sun. Fresh to locally strong E to SE winds are expected in the Gulf of Honduras at night through the weekend. A small area of low pressure over eastern Nicaragua is producing disorganized shower and thunderstorm activity off eastern Honduras. The low could move over the Gulf of Honduras on Friday where development, if any, is expected to be slow to occur. Looking ahead, Hurricane Larry will move NE of the Leeward Islands by late Sun into Mon and hurricane conditions are possible in the adjacent Atlantic waters by that time. At a minimum, large swells generated by Hurricane Larry are expected to propagate across the waters east of the Leeward on Sun, likely spreading beyond 65W Mon and Mon night. ATLANTIC OCEAN... Please see the Special Features section for details on Hurricane Larry. An elongated north to south upper-level cyclonic circulation center is near 29N69W. Scattered showers and isolated thunderstorms are north of 26N and west of 68W. A surface trough extends from 31N25W to 25N34W. Isolated showers and thunderstorms are within 60 nm east of the trough north of 29N. A 1023 mb high pressure center is located near 34N39W and a 1021 mb high is analyzed nea 32N52W. As for the forecast, fresh southwest winds off northeast Florida will shift northeast of the area by this evening. These winds are ahead of a cold front forecast to weaken as it moves across the northern waters W of 70W Sat through Sun night. Looking ahead, Hurricane Larry will move NE of the Leeward Islands by late Sun into Mon and hurricane conditions are possible in the adjacent Atlantic waters by that time. At a minimum, large swells generated by Hurricane Larry are expected to propagate across the waters east of the Leeward on Sun, likely spreading beyond 65W Mon and Mon night. $$ Aguirre