000 AXNT20 KNHC 052348 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT Tue Sep 5 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 2315 UTC. ...SPECIAL FEATURES... The center of Hurricane Irma at 06/0000 UTC is near 17.2N 60.5W, or about 75 NM to the E of Antigua. Irma is moving W, or about 280 degrees, at 13 knots. The estimated minimum central pressure is down to 916 mb. The maximum sustained wind speeds are 160 kt with gusts to 195 kt. Irma is an extremely dangerous Category Five hurricane on the Saffir-Simpson Hurricane Wind Scale and is the strongest hurricane observed in the Atlantic basin outside of the Caribbean and the Gulf of Mexico. Irma has a well defined eye about 20-25 NM in diameter surrounded by numerous strong convection within 120 nm of the center. Scattered moderate isolated strong convection is elsewhere within 210 Nm of the center. Conditions are rapidly deteriorating over the northern Leeward Islands. For additional information please read the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the Forecast/ Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. The center of Tropical Storm Jose at 05/2100 UTC is near 12.5N 40.6W, or about 1215 NM E of the Lesser Antilles, moving W, or about 280 degrees, at 10 knots. The estimated minimum central pressure is 1006 mb. The maximum sustained wind speeds are now 40 kt with gusts to 50 kt. Numerous strong convection is within 90 NM in the SE and 60 NM in the NW semicircles. 10N-13N between 38W-41W. Scattered moderate convection is noted elsewhere within 180 NM in the SE and 90 NM in the NW semicircles. The environment in which Jose is located in appears to be quite conducive for development for the next three days as the SSTs are very warm, the vertical shear is very low, and there is abundant mid-level moisture. Jose may become a hurricane Wed night or Thu. For additional information please read the latest NHC Forecast/ Advisory under AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details. The center of newly formed Tropical Depression Thirteen is in the near 22.4N 96.7W or about 70 NM E of Tampico, Mexico, drifting E at 2 kt. The estimated minimum central pressure is 1008 mb. The maximum sustained wind speeds are 30 kt with gusts to 40 kt. Scattered strong convection was noted within 75 NM in the E and 45 NM in the W semicircles. The upper level shear is forecast to gradually lessen, which combined with the very warm Gulf of Mexico waters should result in gradual strengthening. The system could become a tropical storm on Wed. For additional information please read the latest NHC Forecast/ Advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details. ...TROPICAL WAVES... A tropical wave is off the coast of W Africa. Its axis extends from 17N21W to 06N22W, moving W at 10 kt. SSMI TPW imagery shows the wave is in a very moist environment. The wave is also within a distinct 700 mb trough. Convection associated with the wave has dissipated for now. Scattered showers are noted within 120 nm of the wave axis. A tropical wave is in the central Caribbean with axis extending from E Cuba near 22N76W to the coast of Panama near 09N78W, moving W at 10-15 kt. SSMI TPW imagery shows the wave is in a moderately moist environment. The wave is also within a distinct surface and 700 mb trough. Scattered orographically forced thunderstorms are occuring over Cuba with weakening activity noted over Jamaica and Hispaniola. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 14N17W to 10N20W to 08N25W to 10N32W. Scattered moderate convection was noted from 05N-07N between 30W-34W. ...DISCUSSION... GULF OF MEXICO... See the special feature section above for additional information on newly formed Tropical Depression Thirteen. Water vapor imagery and 250 mb streamlines indicated that Tropical Depression Thirteen was being sheared by moderate to strong westerly winds between an anticyclone over Mexico near 19N101W and and upper level shortwave trough along the Rio Grande river. The overall flow over the Gulf was anticyclonic and diffluent in nature providing good ventilation for the system with an extensive area of mid to high clouds covering the entire basin. Scattered embedded showers were noted over the central Gulf from 23N to28N between 85W and 92W. Winds were light over most of the remainder of the Gulf of Mexico outside the immediate area of Tropical Depression Thirteen. CARIBBEAN SEA... Category 5 Hurricane Irma is approaching the northern Leeward Islands. For additional information see the Special Features section above. The upper level outflow from Irma is expanding over the northeastern Caribbean including Puerto Rico and the windward islands north of Grenada. Surface observations from Buoy 42060 show northerly winds increasing to 20-25 KT with seas building to 10 FT. Elsewhere over the Caribbean, the tropical wave over the central Caribbean is lacking in convection except over Cuba, Jamaica and Hispaniola. The eastern extent of the East Pacific monsoon trough traverses Costa Rica and Panama intersecting with the tropical wave. ...HISPANIOLA... Weakening showers and thunderstorms were over the northern interior sections of Haiti and the Dominican Republic. Upper level subsidence ahead of Hurricane Irma was spreading westward over the Dominican Republic. As Hurricane Irma tracks north of Puerto Rico, upper level outflow and eventually showers and thunderstorms will spread over the island with increasing NW to N winds. A Hurricane Warning is in effect for the Dominican Republic from Cabo Engano to the northern border with Haiti. Tropical Storm warnings are is in effect for the Dominican Republic from Cabo Engano to the southern border with Haiti. A hurricane watch is in effect for Haiti from the northern border with the Dominican Republic to Le Mole St. Nicholas. Refer to Special Features above for further details. ATLANTIC OCEAN... Category 5 Hurricane Irma and T.S. Jose are over the Atlantic. A tropical wave is also off the coast of W Africa. See above for additional information. Scattered moderate convection is over the W Atlantic from 29N-32N between 77W-80W. A Surface trough is also over the W Atlantic from 28N73W to the central Bahamas near 23N77W. Another surface trough is over the E Atlantic from 31N33W to 24N36W. Scattered showers are within 90 nm of this trough. A 1030 mb high is centered over the north central Atlantic near 39N43W. Another 1028 mb high is centered over the E Atlantic near 42N24W. These features dominated the flow to the north of the tropical cyclones in the basin. For additional information please visit http://www.hurricanes.gov/marine $$ Cobb