849 AXNT20 KNHC 141117 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Thu Sep 14 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 0600 UTC surface analysis and satellite imagery through 1020 UTC. ...SPECIAL FEATURES... The center of Hurricane Lee, at 14/0900 UTC, is near 29.1N 68.1W, or about 255 nm SW of Bermuda, moving N at 8 kt. Maximum sustained winds are near 85 kt with gusts to 105 kt. Minimum central pressure is 953 mb. Lee is a very large hurricane. Hurricane force winds extend outward up to 90 nm from the center and tropical storm force winds extend outward up to 250 nm. Seas of 12 ft or greater extend outward from the center 435 nm NE quadrant, 420 nm SE quadrant, 390 nm SW quadrant and 500 nm NW quadrant. The maximum sea heights are 46 feet. Scattered moderate to isolated strong convection is within 180 nm S semicircle and 360 nm N semicircle. Hurricane, Tropical Storm and Storm Surge Watches and Warnings are in effect for portions of coastal New England, Atlantic Canada and Bermuda. The center of Hurricane Margot, at 14/0900 UTC, is near 35.9N 40.3W. Margot is moving toward the NNE at 5 kt. The estimated minimum central pressure is 979 mb. The maximum sustained wind speeds are 65 kt with gusts to 80 kt. From 29N to 31N between 39W and 49W, seas are 10-12 ft in N swell with winds up to 20 kt. The winds over 25 kt associated with Margot will remain N of 31N for the remainder of the cyclone's lifetime. Invest AL97 in the Central Tropical Atlantic: A broad area of low pressure along a tropical wave is near 13N37W. Scattered moderate to strong convection is noted from 10N to 19N between 36W and 44W. Environmental conditions appear favorable for further development of this system, and a tropical depression is likely to form during the next couple of days while the low moves west- northwestward to northwestward at 10 to 15 kt across the central tropical Atlantic. The chance of this feature developing into a tropical cyclone during the next 48 hours is high. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 33W, from 19N southward, moving westward 10 knots. Scattered moderate to strong convection is noted from 06N to 16N between 27W and 35W. A 1011 mb low pressure center is nearly stationary along 15N48W. No significant convection is currently associated with this feature. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Senegal near 14.5N17W to AL97 low pressure near 13N37W to low pres near 15N48W. Outside of convection described above, scattered to numerous moderate to strong convection is from 04N to 11.5N between 24W and the African coast. Scattered moderate to strong convection is noted to the NW of AL97, from 19N to 25.5N between 42W and 47W. ...GULF OF MEXICO... A stationary frontal boundary extends just inland from the coast through the southern sections of Alabama, to southern Mississippi, to Louisiana, to East Texas, and beyond south central Texas. A 1013 mb high pressure center is near 30N86W. Scattered moderate convection is across the extreme SE Texas and SW Louisiana coastal waters N of 28.5N and within 60 nm of the Mexican coast across the Bay of Campeche. Fair skies prevail elsewhere across the basin. Light to gentle anticyclonic wind flow prevails across the basin, with E winds of 10 to near 15 kt across the waters NW of the Yucatan Peninsula, and SE winds 10 to 15 kt across the upper Mexican and S Texas coastal waters. Seas are near 3 ft across these areas, and 2 ft or less across the remainder of the basin. A weak ridge across the northern Gulf will dominate the basin throughout the forecast period, supporting mainly light to gentle winds N of 24N and gentle to moderate winds S of 24N. Scattered thunderstorms can be expected across the western Yucatan and eastern Bay of Campeche each late afternoon and evening through the period. ...CARIBBEAN SEA... Hurricane Lee continues to interrupt the pressure pattern across the basin, with a weak and broad trough extending from Lee SSW across Hispaniola to near 17N72W. Moderate SE to S winds are occurring E of 70W, while gentle to moderate winds are across NW portions. Winds across the A-B-C Islands and northern Colombia area NE at 15 kt or less. Seas area generally slight to moderate across the basin due to weaker than normal winds. However, large northerly swell from Lee continues to move through the passages of the NE Caribbean and into the eastern Caribbean waters, likely reaching the coasts of Venezuela. Recent buoy observations along the NW coast of Puerto Rico, and altimeter date through the Mona Passage show seas of 7-8 ft in NNW in the northern Mona passage diminishing to 6 ft across the Caribbean immediately to the south along 15N.This N-NW swell from Lee is assumed to have peaked across the adjacent Atlantic in recent hours. Hurricane Lee will continue moving N across the western Atlantic and pass W of Bermuda tonight. Large N-NW swell across the adjacent Atlantic and moving through the NE Caribbean Passages will gradually diminish this afternoon and tonight and then decrease quickly Fri. Moderate E trade winds will return to the Caribbean on Fri. ...ATLANTIC OCEAN... Please, read the SPECIAL FEATURES section, for details about Hurricane Lee, Hurricane Margot, and the INVEST AL97. Atlantic high pressure is drapped across Hurricane Margot, and to the NE of Hurricane Lee, and is producing moderate winds circulating around both of these systems to the N of 20N. The entire discussion area N of 20N is dominated by swell from Lee and Margot. Moderate to fresh cyclonic winds are around the periphery of Lee and are brushing the Bahamas and the Greater Antilles. Seas across this area are 8 to 12 ft in NW swell between the NE Caribbean Islands and 22N, and 10-12 ft in NE swell across the nearshore Atlantic waters of the Bahamas. Strong SE swell is moving into the coastal waters of Florida and Georgia this morning, where coastal buoys are reporting seas around 5 ft. However farther offshore, this swell is producing seas of 7 to 10 ft to the W of 78W. A broad easterly wind surge is occurring to the N of AL97 from 15N and 22N between 30W and 40W, where seas are 8 to 9 ft in mixed E and N swell. Active convection will continue across this region for the next 24 hours or more. For the forecast W of 55W, Hurricane Lee will continue moving northward and reach near 30.7N 68.2W this afternoon, pass to the W of Bermuda tonight and reach near 33.3N 67.7W Fri morning, then continue northward across the NW Atlantic through the weekend. Long-period swell generated by Lee is expected to impact all waters north through east of the Bahamas through the weekend. High pressure will build across the area late Fri through Sun. Low pressure across the eastern Atlantic, AL97, will approach the far eastern part of the area Mon and Mon night, possibly as a tropical cyclone. $$ Stripling/Hagen