000 AXNT20 KNHC 050004 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT SUN SEP 04 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 2245 UTC. ...SPECIAL FEATURES... Post-tropical cyclone Hermine is centered near 37.2N 69.3W, about 265 nm SSE of the eastern tip of Long Island, and about 290 nm E of Ocean City Maryland. Hermine is moving slowly ENE, or 70 degrees, at 4 knots. The center of Hermine is forecast to meander slowly offshore of the mid-Atlantic coast for the next couple of days. The estimated minimum central pressure is 999 mb. Maximum sustained winds are 60 knots with gusts to 75 knots. Convective precipitation: Scattered moderate in the Atlantic Ocean from 38N to 40N between 62W and 69W and from 34N to 37N between 61W and 64W. 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... An Atlantic Ocean tropical wave extends from 09N33W through low pres 1012 mb centered at 20N35W to 21N35W. The wave is moving westward at 10 to 15 knots. The wave shows up well in satellite imagery. Convective precipitation: Isolated moderate from 20N to 27N between 30W and 37W. Scattered moderate from 05N to 14N between 29W and 39W and in the vicinity of the low from 21N to 26N between 33W and 38W. A layer of Saharan air is inhibiting convection on the W side of this wave between 14N and 21N. An Atlantic Ocean tropical wave extends from 11N61W through low pres 1008 mb centered at 15N60W to 19N60W. The wave is located just E of the Windward Islands and is moving westward at 15 to 20 knots. Convective precipitation: scattered moderate and isolated strong from 12N to 17N between 55W and 66W. Latest satellite-derived wind data show an area of fresh to strong NE to E winds accompanies this wave from 13N to 19N between 54W and 67W. Model guidance suggests this wave will continue westward and bring associated convection to the central Caribbean between Colombia and Hispaniola on Tue. A Caribbean Sea tropical wave entering central America extends from 10N84W to 17N84W. Convective precipitation: Scattered moderate and isolated strong convection is mainly located over Costa Rica...Nicaragua and Honduras from 10n to 16N between 82W and 88W. An upper-level trough over southeastern Mexico is providing an area of divergent upper-level winds over this system. ...ITCZ/MONSOON TROUGH... The Monsoon Trough heads westward from Senegal on the African coast at 14N17W to 11N35W to 12N49W. The ITCZ continues from 12N49W to 14N58W. Convective precipitation: Scattered moderate from 03N to 09N between 17W and 27W, and from 07N to 13N between 39W and 50W. ...DISCUSSION... ...THE GULF OF MEXICO... An upper level cyclonic circulation center is in the NW corner of the area, along the Texas coast. Upper-level cyclonic wind flow covers the Gulf of Mexico from 23N northward from 90W westward. A surface trough follows the United States gulf coast from eastern Texas to northern Florida. Another surface trough was situated along the Mexican gulf coast from near Veracruz to near Ciudad Victoria. Only minimal convection is associated with the trough over eastern Mexico. Scattered moderate and isolated strong convection associated with the trough along the northern Gulf coast is seen from 28N to 31N between 81W and 98W. Upper- level ridging is aiding the convection along the northern Gulf coast. An area of upper-level convergence to the E of an upper- level trough is approaching the Mexican gulf coast. This should begin to restrict convection in this area on Monday. ...THE CARIBBEAN SEA... An upper-level low is centered SW of Haiti near 17N75W. Upper- level convergence in the vicinity of this feature is restricting convection over much of the Caribbean. Divergent upper-level winds on the W and E sides of the low are aiding convection associated with the tropical waves about to enter the eastern Caribbean and central America. The upper-level low will continue to progress westward during the next several days. Convective precipitation associated with tropical waves cover the Caribbean Sea E of 67W and W of 82W. See the tropical waves section for more details. ...HISPANIOLA... Fair weather prevails across the island due to strong subsidence aloft as indicated by water vapor imagery. Stable and fair weather is expected to continue tonight. On Monday and Tuesday, a moist air mass associated with an approaching tropical wave will bring increased shower coverage. Drier weather is expected by Thursday as the wave moves away to the W. ...THE ATLANTIC OCEAN... Post-tropical cyclone Hermine remains 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 weak surface trough stretches from along the Cuban coast at 23N80W to east of Florida at 27N78W. Only minimal deep convection is found in the vicinity of the trough. The trough is moving W away from Andros Island in the western Bahamas toward the east coast of Florida. The remainder of the basin is dominated by a weak and broad surface ridge stretching from 30N34W to 27N75W. Model guidance suggests this ridge will be reinforced by high pressure building southeastward from north America. 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