000 AXNT20 KNHC 201148 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 648 AM EST SUN NOV 20 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 0600 UTC surface analysis and satellite imagery through 1115 UTC. ...SPECIAL FEATURES... A 1006 mb low pressure center is in the SW corner of the Caribbean Sea near 11N81W, off the coasts of Panama, Costa Rica, and Nicaragua. Convective precipitation: Scattered moderate to isolated strong covers the SW corner of the Caribbean Sea from 14N southward from 80W westward. Overall environmental conditions are marginally conducive for development into a tropical cyclone. It is possible that a tropical depression may form during the next few days, as the low pressure center moves slowly and erratically. The chance of formation into a tropical cyclone during the next 48 hours is medium. Gulf of Mexico Gale Warning: A cold front is along 27N82W 23N94W 18N95W. Expect gale-force NW-to-N winds and sea heights ranging from 9 feet to 14 feet, to the south of 21N to the west of 95W. Convective precipitation: isolated moderate from 23N southward from 91W westward. Rainshowers are possible also from 26N southward. Please read the High Seas Forecast product under AWIPS/WMO headers HSFAT2/AXNT20 KNHC for more details. ...THE ITCZ/THE MONSOON TROUGH... The Monsoon Trough reaches the coastal areas of Senegal near 14N17W to 11N20W. The ITCZ continues from 11N20W to 05N30W and 06N35W. Convective precipitation: scattered moderate to strong from 05N to 10N between 24W and 28W. Rainshowers are possible elsewhere from 10N southward from 60W eastward. ...DISCUSSION... ...THE REST OF THE GULF OF MEXICO... Surface anticyclonic wind flow has been spreading across the rest of the area that is to the north of the advancing cold front. The information about the cold front and gale-force winds is in the SPECIAL FEATURES section. Gale-force winds are blowing in the Gulf of Tehuantepec on the eastern Pacific Ocean side of southern Mexico. Please read the Eastern Pacific Ocean HIGH SEAS FORECAST...MIAHSFEP2/FZPN03 KNHC...and the Eastern Pacific Ocean TROPICAL WEATHER DISCUSSION...MIATWDEP/AXPZ20 KNHC...for more details. ...LOW LEVEL CLOUD CEILINGS AND WEATHER FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N NORTHWARD AND FROM 88W WESTWARD... LIFR: none. IFR: none. MVFR: KVQT and KVOA. LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA... from TEXAS to FLORIDA: VFR/no ceilings. ...FROM THE ATLANTIC OCEAN INTO THE CARIBBEAN SEA... A deep layer trough passes through the area that is about 360 nm to the east of Bermuda, ending near a point that is about 600 nm to the SE of Bermuda. A secondary upper level trough passes through the area that is about 480 nm to the W of Bermuda, across the Bahamas, to NW Cuba, and into the NW corner of the Caribbean Sea. The trough that is to the east and southeast of Bermuda supports a cold front that passes through 32N54W to 27N56W to 22N60W. A stationary front continues from 22N60W, across NW Puerto Rico, to 16N72W in the Caribbean Sea. The trough that is to the west of Bermuda is supporting the cold front that is moving through the Gulf of Mexico, with the gale-force winds. Convective precipitation in the Atlantic Ocean: widely scattered moderate to isolated strong from 24N northward between 48W and 60W. Isolated moderate to locally strong from 18N in the Caribbean Sea to 24N between 48W and 76W. Convective precipitation in the Caribbean Sea: Some of the precipitation that was only in the coastal sections of Colombia and Venezuela six hours ago, now has moved into the Caribbean Sea. Scattered to numerous strong within 30 nm to 60 nm on either side of 13N69W 14N73W 17N75W. Isolated moderate to locally strong elsewhere from 18N southward between 67W and 80W. ...THE REST OF THE CARIBBEAN SEA... Upper level SW wind flow covers the area to the east of the line that runs from SE Cuba, into the Gulf of Honduras. An upper level ridge runs from NW Venezuela/N Colombia, to 20N81W. The 24-HOUR rainfall totals in inches for the period ending at 20/0000 UTC...according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...is 0.02 in Guadeloupe, and 0.02 in Merida in Mexico. ...HISPANIOLA... Upper level SW wind flow is moving across the entire area. Please refer to the section with the title FROM THE ATLANTIC OCEAN INTO THE CARIBBEAN SEA for more details. An upper level trough passes through the Atlantic Ocean, across NW Cuba, into the NW corner of the Caribbean Sea. A stationary front cuts across N central sections of the Caribbean Sea. Convective precipitation: isolated moderate across the island, and in the coastal waters/coastal areas. SURFACE OBSERVATIONS...for Port-au-Prince in Haiti, at 20/0200 UTC: VFR/no ceiling. few cumulonimbus clouds. for the DOMINICAN REPUBLIC: Barahona: VFR. few cumulonimbus clouds. Santo Domingo: the rain has stopped for the moment. VFR. few cumulonimbus clouds. La Romana: MVFR. ceiling at 1600 feet. few cumulonimbus clouds. Punta Cana: light rain. Santiago: MVFR. ceiling at 1400 feet. Puerto Plata: VFR. The GFS MODEL forecast for 250 MB shows that SW wind flow will move across the area during the next 48 hours, with a ridge. The GFS MODEL forecast for 500 MB shows that SW wind flow will move across the area during the first 30 hours to 36 hours of the next 48 hour forecast period. A ridge will be in the SE corner of the Caribbean Sea. A trough will be approaching from the west. The trough reaches Haiti, spreading cyclonic wind flow across the western half of the island, and S wind flow elsewhere for the rest of the forecast period. The GFS MODEL forecast for 700 mb shows that anticyclonic wind flow will move across the area during the first 30 hours or so of the 48-hour forecast period. NE wind flow will continue for the rest of the forecast period. ...THE REST OF THE ATLANTIC OCEAN... An upper level trough is along 31N26W, to a 22N39W cyclonic circulation center, to 15N39W and 08N51W. A surface trough is along 40W from 18N to 24N. A second surface trough is along 14N38W 10N43W. Convective precipitation: isolated moderate from 20N to 28N between 30W and 42W. Isolated moderate from 07N to 09N between 52W and 55W. Rainshowers are possible also from 10N northward between 20W and 50W. Isolated moderate to locally strong within 300 nm on either side of 08N42W 14N31W beyond 25N20W, on the eastern side of the upper level trough. Broad surface anticyclonic wind flow covers the area from 20N northward between Africa and 50W, except near the two surface troughs. For additional information please visit http://www.hurricanes.gov/marine $$ MT