000 AXNT20 KNHC 292304 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 604 PM EST Wed Nov 29 2017 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 2215 UTC. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 10N14W to 10N19W. The Intertropical Convergence Zone axis extends from 10N19W to 05N34W to 02N45W. Widely scattered moderate convection is from 03N-08N between 28W-37W. ...DISCUSSION... GULF OF MEXICO... Relatively broad middle to upper level ridging is over much of the Gulf basin this evening with a middle to upper level shortwave trough progressing eastward over the Ohio River valley. A 1019 mb low is centered across SE Oklahoma with the associated cold front extending southward to near Galveston Bay then to the Texas coast near Corpus Christi. The front continues to dissipate as the mid- level energy progresses eastward. A surface trough extends from the cold front near 30N94W S-SE to the northern coast of the Yucatan peninsula near 22N89W. While water vapor imagery indicates very dry conditions aloft...shallow low-level moisture in the vicinity of the trough is supporting isolated showers within 90 nm either side of the boundary and S of 26N between 87W-90W. Otherwise...moderate E winds prevail east of the surface trough and generally gentle to moderate N winds prevail W of the surface trough. The trough is forecast become diffuse by early Sunday with ridging anchored across the eastern CONUS influencing the basin with gentle to moderate E-SE winds. CARIBBEAN SEA... West-northwesterly flow aloft prevails over much of the basin this evening on the northern periphery of an upper level anticyclonic circulation anchored in the East Pacific waters S of Panama near 04N83W. Generally dry air aloft and overall stable conditions are noted across the central and eastern Caribbean this evening...with most atmospheric moisture centered around Panama. A surface trough extends from 19N80W to 10N81W and intersects the monsoon trough axis analyzed along 10N. Scattered showers and tstms are occurring S of 12N between 75W-84W and largely enhanced due to favorable upper level divergence. Isolated showers are elsewhere W of 84W across the NW Caribbean waters...pushing into interior portions of Central America. Farther east...the only other area of note is a surface trough analyzed SE of Trinidad and Tobago from 09N61W to 13N56W. Scattered showers and isolated tstms are occurring within 150 nm either side of the boundary...continuing to impact eastern Venezuela...Trinidad and Tobago...and likely Barbados during the late evening hours. Otherwise...moderate to fresh trades will persist E of 80W into Thursday...with slightly strong winds anticipated within 120 nm of the Colombia coast through the overnight hours. ...HISPANIOLA... Generally clear skies and fair weather conditions are across the island this evening as the influence of dry westerly flow aloft remains in place over the region. Little change is expected through Friday. ATLANTIC OCEAN... A middle to upper level shortwave trough is noted over the SW North Atlc in the vicinity of 29N74W that supports a surface trough extending from 29N72W across the central Bahamas to 23N79W. Low-level moisture convergence along with middle to upper level divergent E of the trough axis along 74W is supporting scattered showers and tstms occurring from 22N-33N between 60W-76W. By late Thursday a low is expected to develop across the far eastern offshore water zones and move NE into the central Atlc waters Thursday night into Friday. Farther east...a vigorous middle to upper level low is centered over the central North Atlc near 39N40W that supports a storm-force 990 mb low nearly collocated with the upper level feature. The associated cold front enters the discussion area near 32N38W SW to 30N44W then W to 29N53W. Isolated showers are possible within 90 nm either side of the front. To the east...an old frontal boundary...now analyzed as a surface trough extends from 32N30W to 28N32W to 25N36W. Scattered showers and widely scattered tstms are occurring N of 24N between 26W-36W. The remainder of the central and eastern Atlc is under the influence of rather benign and tranquil conditions this evening S of 25N. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN