000 AXNT20 KNHC 060003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT MON SEP 5 2016 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2330 UTC. ...SPECIAL FEATURES... Post-tropical cyclone Hermine is centered near 39.3N 69.5W,or about 150 nm SE of the eastern tip of Long Island. Hermine is moving west-northwest, or 300 degrees, 6 knots. The estimated minimum central pressure is 997 mb. Maximum sustained winds are 60 knots with gusts to 75 knots. Scattered moderate convection was noted within 180 nm in the NW semicircle of Hermine. Regional radar imagery indicated scattered showers moving westward across eastern Massachusetts, Rhode Island and eastern Long Island. As Hermine tracks over cooler waters it is forecast to gradually weaken through the forecast period. Large waves generated by Hermine will affect the U.S. east coast from the mid-Atlantic states northward along the coast of southern New England through at least Tuesday. These waves are likely to cause life-threatening surf and rip current conditions, and significant beach erosion. Please read the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC and the Forecast/Advisory under the AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. ...TROPICAL WAVES... A tropical wave is over the central Atlc was relocated earlier and currently extends from 10N to 20N with axis along 37W/38W, moving west at 10-15 kt. The wave is in a region of favorable deep layer wind shear from 10N to 20N, however continuous intrusion of Saharan dry air and dust into the wave environment is hindering convection and any development at the time. A tropical wave is over the eastern Caribbean Sea and extends from 10N to 20N with axis along 65W/66W, moving W at 15 kt within the last 24 hours. A 1009 mb center of low pressure is associated with the wave, located near 15N66W and is expected to move W to near 16N73W within 24 hours. Abundant moisture in the vicinity of the wave along with a diffluent environment aloft support scattered moderate to strong convection over the NE Caribbean from 14N to 18N between 62W and 68W. San Juan radar depicted a fairly well defined low to mid level circulation near 17N66W with scattered to numerous showers passing over and to the south of the island with the potential for very heavy rainfall into early Tuesday. The 12Z San Juan rawindsonde showed winds of 40 kt at 800 to 825 mb. A tropical wave moved over the Yucatan Peninsula, and northern Central America into the NE Pacific waters. The wave extends from 08N to 21N with axis near 90W, moving at 15 kt within the last 24 hours. The wave is in a favorable deep layer wind shear environment that along with diffluent flow aloft support scattered showers over western Yucatan and over Honduras and Nicaragua. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 17N16W to 10N21W to 07N25W to 10N30W to 11N37W. Scattered moderate to isolated strong convection is from 04N to 08N between 24W and 31W. ...DISCUSSION... ...THE GULF OF MEXICO... Weak surface ridging prevails across the Gulf waters, except for the far southern portion of the basin where low level moisture convergence associated with the tropical wave along 90W is supporting scattered thunderstorms across the western Yucatan peninsula into the far eastern Bay of Campeche. Surface observations indicated moderate E to SE winds basin-wide with seas generally 2 to 4 FT. Cloudiness and scattered showers and thunderstorms over the N-central Gulf coast and adjacent waters are associated with the remnants of a former surface trough. The tropical wave moving across the Bay of Campeche over the next few days supports enhanced activity there. Elsewhere surface ridging will remain as the main feature the next two days. ...THE CARIBBEAN SEA... The main concern for the basin is a vigorous tropical wave that is moving across the eastern Caribbean and Puerto Rico. This wave is supporting scattered showers and thunderstorms from 14N to 18N between 62W and 68W. Locally strong winds to near gale force as possible in some of the heavier squalls passing over and to the south of Puerto Rico. This disturbance will continue to produce locally heavy rainfall and gusty winds over portions of Puerto Rico and spread over Hispaniola on Tuesday. The concern here is for very heavy rainfall over Hispaniola. Please refer to the tropical waves section for details. The monsoon trough supports scattered heavy showers in the SW basin within 150 nm off the coasts from Honduras to Colombia. Fresh to locally strong winds are noted elsewhere in the Caribbean from 11N to 17N between 61W and 79W. ...HISPANIOLA... Increasing multilayered cloudiness is spreading across the Dominican Republic in advance of the strong tropical wave along 66W. The potential for very heavy rainfall exists on Tue into Wed across the island as the strong tropical wave continues westward in the Caribbean. Drier weather is expected by Thursday as the wave moves away from the island. ...THE ATLANTIC OCEAN... Post-tropical cyclone Hermine is N of forecast waters. Please refer to the special features section for details. Two tropical waves are moving across the basin. Please refer to the tropical waves section for details. A surface trough prevails in the SW N Atlc waters from 30N71W to a 1016 mb low pressure near 28N73W to near Andros Island, supporting isolated showers within 90 nm either side of its axis. Another surface trough is over the N central extending from a 1018 mb low near 29N51W to 24N58W. the low was moving west at 15 kt. Another low pressure area was located near 23N38W with an associated trough extending NE to near 28N35W. Convective activity was located well to the north of this feature in shearing SW flow aloft, generally from 26N to 32N between 28W and 35W. Lastly, a 1012 mb low in the deep tropics near 12N45W detached from the tropical wave to its east supports scattered heavy showers and isolated tstms from 08N to149N between 40W and 46W. The remainder of the basin is dominated by a broad but weak surface ridge. For additional information please visit http://www.hurricanes.gov/marine $$ COBB