000 AXNT20 KNHC 070930 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 530 AM EDT Sat Oct 7 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... Hurricane Nate is centered near 24.5N 87.0W at 07/0900 UTC or about 297 nm south-southeast of the mouth of the Mississippi river. Nate is moving north-northwest at 19 kt. Estimated minimum central pressure is 987 mb. Maximum sustained wind speed is 70 kt with gusts to 85 kt. Numerous strong convection is from 23N-25N between 85W-88W. Scattered moderate to isolated strong convection and tstms are elsewhere from 17N-29N between 82W-92W. See the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the full Advisory/Forecast under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... A tropical wave came off the coast of Africa this morning. Its axis extends from 11N15W to 01N14W expected to move W at 10 kt during the next 24 hours. Satellite derived date indicate the wave is in a low vertical shear region while the CIRA LPW imagery show abundant low level moisture in the wave environment. This combined with upper level divergent flow support numerous moderate convection and scattered tstms from 02N-12N between 11W-18W. A tropical wave is in the central Atlc associated with a 1011 mb low located near 06N43W, which is expected to move NW towards 10N46W within the next 24 hours. The wave axis extends from 14N40W to the low center to 05N43W, and has been moving W at 10 kt. The wave is in a region of strong vertical wind shear and is experiencing dry air intrusion to its environment as indicated by CIRA LPW imagery at the lower levels. This is limiting convection to scattered moderate from 06N-14N between 39W-46W just underneath middle to upper level divergent flow. A tropical wave is in the central Atlc with axis extending from 19N48W to 08N53W, moving west at 5-10 kt. The wave is in a region of strong vertical wind shear, however CIRA LPW imagery show abundant moisture in the wave environment at the lower levels mainly E of the wave axis where scattered moderate convection is from 13N-17N between 46W-53W just underneath middle level divergent flow. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 13N17W to 08N20W to 04N26W. The ITCZ extends from there to 03N30W to 04N36W. For information about convection see the tropical waves section. ...DISCUSSION... GULF OF MEXICO... The main feature in the basin is hurricane Nate located several nm NNE of the Yucatan Peninsula. Additional strengthening is expected through Saturday up until the time Nate makes landfall along the northern Gulf coast Saturday night. In Mexico, a storm surge will raise water levels by as much as 1 to 3 feet above normal tide levels along the immediate coast in areas of onshore winds on the Yucatan Peninsula and the adjacent islands. Near the coast, the surge will be accompanied by large and destructive waves. Nate is expected to produce rain accumulations of 6 inches in the Eastern Yucatan and western Cuba through Monday. For further details, see special features. Scatterometer data show a surface trough NW of Nate over the NW Gulf along 28N94W to 23N93W producing scattered showers and tstms within 15 nm either side of its axis. CARIBBEAN SEA... Scattered moderate to isolated strong convection along with scattered tstms prevail across the NW Caribbean W of 80W, including the Yucatan channel and W Cuba. This precipitation activity is associated with hurricane Nate centered over the SE Gulf of Mexico. Refer to the special features section above for details. Nate is a broad tropical cyclone, which outer rainbands continue to affect the Cayman Islands, Jamaica and, central and eastern Cuba. Isolated showers extends over Hispaniola and are also being enhanced by a surface trough over SW N Atlc waters. Water vapor and CIRA LPW imagery show dry air over the central and eastern Caribbean, which is resulting in mainly clear skies and fair weather conditions. Gentle to moderate E-SE winds are expected to prevail E of 80W through the weekend. Heavy rainfall is expected to continue across the NW Caribbean as Nate tracks northward. ...HISPANIOLA... Isolated showers are over Hispaniola associated with the outer rain bands of Hurricane Nate centered over SE Gulf of Mexico waters. These showers are also being enhanced by a surface trough over SW N Atlc waters N of the Mona Channel. Similar conditions are expected through the weekend with showers increasing Sunday morning due to closer proximity of the surface trough to the Dominican Republic. ATLANTIC OCEAN... Three tropical waves are moving across the basin. Refer to the section above for details. In the SW N Atlc waters, a surface trough underneath middle to upper level diffluent flow is generating scattered heavy showers and isolated tstms from 19N to 30N between 63W and 79W. In the north-central Atlc waters, a stationary front extending from 30N37W to 25N46W continues to weaken and is expected to become a remnant surface trough tonight. SE of this front a pre-frontal trough extends from 25N38W to 17N44W. The remainder of the basin is under the influence of a surface ridge, anchored by a 1026 mb high centered near 35N53W. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos