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Tropical Weather Discussion


Issued Active alert

Start Time

Tue 09/18/2018 07:42 AM EDT

End Time

Tue 10/02/2018 07:42 AM EDT



Full Alert Message

Tropical Weather Discussion NWS National Hurricane Center Miami FL 742 AM EDT Tue Sep 18 2018 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 0600 UTC surface analysis and satellite imagery through 1115 UTC. ...SPECIAL FEATURES Tropical Depression Joyce centered near 32.9N 27.6W at 18/0900 UTC or 310 nm S of the Azores moving SSE at 5 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Joyce remains an organized low level circulation under strong westerly vertical shear, with minimal deep convection. A turn toward the south is forecast later today, followed by a motion toward the southwest on Wednesday and Thursday. Gradual weakening is expected during the next couple of days, and Joyce is forecast to become a remnant low later today or tonight. See the latest NHC forecast/ advisory under AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC for more details. ...TROPICAL WAVES... A central Atlantic tropical wave is along 56W from 03N-18N, moving west at 20 kt. Model guidance indicates the wave is associated with a 700 mb trough. It is near the leading edge of an extensive area of dry Saharan air from 12N-25N between 35W-55W. Scattered showers are within 90 nm of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from W Africa near 14N17W to 10N20W. The ITCZ extends from 10N20W to 07N30W to 06N56W. Scattered moderate to strong convection is from 03N-09N between 20W-40W, and from 05N-12N between 40W-51W. ...DISCUSSION... GULF OF MEXICO... An upper level low is over the western gulf near 26N94W. A 1015 mb surface high is over the NW Gulf near 27N94W. Another 1015 mb high is over the NE Gulf near 28N84W. Light anticyclonic winds prevail over the two surface highs. 10-15 kt E winds are over the remainder of the Gulf. A surface trough south of Cuba, the remnants of Isaac, will move west into the SW Gulf on Wednesday. CARIBBEAN SEA... The remnants of Isaac, located south of Cuba, have weakened to a surface trough. Showers associated with the disturbance are mainly east of the trough axis, from 16N-21N between 74W-81W. Environmental conditions are not conducive for re-development to occur. Gentle trades are west of the trough axis, while gentle to moderate trades are over the rest of the central and eastern Caribbean. A tropical wave along 56W is expected to reach the area Wednesday, accompanied by fresh trades and building seas. ATLANTIC OCEAN... Please refer to the Special Features section for details on Tropical Depression Joyce. Also refer to the tropical wave section for a wave along 56W. A broad deep layer trough extends across the central Atlantic from a large upper-level low centered near 28N62W. A surface trough extends NE from the Turks and Caicos to 31N61W. This system is producing scattered showers and thunderstorms mainly SE of the trough axis from 21N-26N between 60W-68W. Broad high pressure is centered near 30N45W. The surface trough will likely weaken over the next 24-48 hours as the high builds westward. For additional information please visit