631 AXNT20 KNHC 041810 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Mon Sep 04 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 1200 UTC surface analysis and satellite imagery through 1750 UTC. The remnants of GERT, at 04/1500 UTC, are a 1001 mb low pressure center that is near 40.5N 51.0W. The remnants are moving NNW, or 330 degrees, 25 knots. The estimated minimum central pressure is 1001 mb. The maximum sustained wind speeds are 45 knots with gusts to 55 knots. Tropical storm-force winds are: within 60 nm of the center in the NE quadrant; within 60 nm of the center in the SE quadrant; within 0 nm of the center in the SW quadrant; and within 30 nm of the center in the NW quadrant. The radius of the sea heights that are 12 feet or greater is: within 60 nm of the center in the NE quadrant; within 300 nm of the center in the SE quadrant; within 180 nm of the center in the SW quadrant; and within 60 nm of the center in the NW quadrant. The maximum sea heights are 18 feet. Please, read the latest HIGH SEAS FORECAST, that is issued by the National Hurricane Center, at the website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and the latest Gert NHC Forecast/Advisory and the Public Advisory, at www.hurricanes.gov, for more details. The center of Tropical Depression Katia, at 04/1500 UTC, is near 28.0N 34.0W. KATIA is moving toward the NW, or 320 degrees, 04 knots. The estimated minimum central pressure is 1009 mb. The maximum sustained wind speeds are 30 knots with gusts to 40 knots. Expect in the forecast waters: from 27N to 31N between 35W and 36W NE winds 20 knots to 25 knots, and sea heights that range from 10 feet to 12 feet. The radius of the sea heights that are 12 feet or greater is: within 90 nm of the center in the NE quadrant; within 0 nm of the center in the SE quadrant; within 0 nm of the center in the SW quadrant; and within 120 nm of the center in the NW quadrant. The maximum sea heights are 12 feet. Precipitation: isolated moderate to locally strong is within 180 nm of the center in the NE quadrant. Please, read the latest HIGH SEAS FORECAST, that is issued by the National Hurricane Center, at the website, https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and the latest Katia NHC Forecast/Advisory and the Public Advisory, at www.hurricanes.gov, for more details. ...INVEST AL951... An Atlantic Ocean tropical wave is along 33W/34W. A 1010 mb low pressure center is along the tropical wave near 11.5N. Precipitation: widely scattered moderate to isolated strong is from 07N to 15N between 30W and 40W. Expect E winds from 20 knots to 30 knots, and sea heights reaching 8 feet, from 12N to 13N between 35W AND 37W. The precipitation pattern continues to show signs of organization. The environmental conditions are forecast to be conducive for more development. This system is expected to become a tropical depression around midweek. More strengthening is likely late this week. The weather system is forecast to move westward to west-northwestward 15 mph to 20 mph in the central and western sections of the tropical Atlantic Ocean. The chance of formation into a tropical cyclone during the next 48 hours is high. Gale-force winds, and sea heights that will range from 10 feet to 13 feet, are forecast from 13N to 15N between 43.5W and 46W. Expect also: winds from 20 knots to 30 knots, and sea heights that range from 8 feet to 11 feet, from 11N to 18N between 40W and 47W. Please refer to the website: www.hurricanes.gov, for more details. ...TROPICAL WAVES... A tropical wave, that is in western Africa, is forecast to move off the African coast in a couple of days. The environmental conditions should support some slow development. It is possible that a tropical depression may form in the far eastern tropical Atlantic Ocean during the latter part of the week. The movement of this feature will be toward the west-northwest 15 mph. A Caribbean Sea tropical wave is along 73W/74W, from 19N southward, moving westward 5 knots to 10 knots. Precipitation: widely scattered moderate to isolated strong is from 15N to the dissipating stationary front between Puerto Rico and Jamaica. Isolated moderate to locally strong is elsewhere from 13N northward between 65W and 80W. A Caribbean Sea tropical wave is along 86W/87W, from 19N southward, moving westward 10 knots to 15 knots. Precipitation: widely scattered moderate to isolated strong is from 16N northward between 83W and Belize. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Senegal near 14N17W, through the INVEST AL95 low pressure center, to 10N39W. The ITCZ continues from 10N39W, to 09N44W 07N53W. Precipitation: numerous strong is from 11N to 17N between 14W and 18W. Widely scattered moderate to isolated strong is from 04N to 12N between 12W and 24W. Isolated moderate to locally strong is elsewhere from 20N southward from 60W eastward. ...GULF OF MEXICO... A dissipating stationary front passes through SE Cuba, to NW Cuba, to SE Louisiana. Moderate to fresh easterly winds are to the east of the dissipating stationary front. Moderate or slower SE winds are to the west of the dissipating stationary front. Precipitation: isolated moderate to locally strong is from 92W eastward, and from 24N to 27N between 94W and 96W. Broad surface high pressure covers the area that is from 27N northward from Alabama eastward. A 1014 mb high pressure center is in interior Mexico near 19N99W. The sea heights are: 5 feet in the SE Gulf of Mexico; 3 feet elsewhere from 90W eastward; from the middle Texas Gulf coast waters to the NE Mexico coastal waters, to the NW Yucatan Peninsula coastal waters; 1 foot off the coast of Louisiana; 2 feet elsewhere. High pressure over the SE US will support moderate E to SE winds across most of the basin through tonight, and gentle to moderate thereafter through mid-week. Afterward, a weak pressure gradient will result in light to gentle winds and slight seas the remainder of the forecast period, with the exception of gentle to moderate winds just W of the Yucatan Peninsula. ...CARIBBEAN SEA... The monsoon trough is along 08N/10N from 74W in Colombia beyond Costa Rica. Precipitation: widely scattered moderate to isolated strong is from 15N southward from 75W westward. Moderate to fresh winds are in the eastern two-thirds of the area. Moderate or slower winds are elsewhere. The sea heights are: from 4 feet to 6 feet from Venezuela northward between Puerto Rico and the eastern parts of the Dominican Republic; from 3 feet to 4 feet elsewhere from 70W eastward; from 2 feet to 3 feet between 70W and 80W; 3 feet from 20N northward; and from 1 foot to 2 feet elsewhere. The 24-hour rainfall totals in inches, for the period that ended at 04/1200 UTC, according to the MIATPTPAN, are: 1.30 in Merida in Mexico. Moderate to fresh trade winds and moderate seas will continue in the central and eastern Caribbean the entire forecast period, except for developing fresh to strong winds in the south-central waters Tue night into Wed. Gentle to locally moderate winds and slight seas will prevail elsewhere. Looking ahead, a tropical wave located several hundred nm SW of the Cabo Verde Islands is likely to become a tropical cyclone within the next 48 hours, and could cross 55W by Fri. ...ATLANTIC OCEAN... Please, read the SPECIAL FEATURES section, for details about T.S. GERT, T.D. KATIA, and the INVEST AL95. A dissipating stationary front passes through 31N53W 23N60W, beyond SE Cuba. An upper level cyclonic circulation center is near 28N43W, between T.D. KATIA and the dissipating stationary front. Precipitation: widely scattered moderate to isolated strong is from 20N northward between 40W and 55W; and within 300 nm to the north of the front from 55W westward. The sea heights are 8 feet and higher from the Greater Antilles northward, from 60W westward, except for sea heights that range from 2 feet to 5 feet between the Bahamas and Florida. The sea heights range from 7 feet to 11 feet from 19N northward between 50W and 60W. The sea heights have been ranging from 3 feet to 6 feet in the remainder of the Atlantic Ocean. Fresh and faster winds are from 29N northward between the dissipating stationary front and 65W. Moderate to fresh NE winds are from 15N to 25N from 26W eastward. Moderate or slower winds are in the remainder of the area. Seas of 7 to 10 ft in N to NE swell are in much of the area that is to the east of 75W and north of 20N today. The swell will gradually subside through Tue. Looking ahead, a tropical wave that is several hundred nm SW of the Cabo Verde Islands is likely to become a tropical cyclone within the next 48 hours, and could cross 55W by Fri. $$ mt/ah