000 AXNT20 KNHC 261734 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 134 PM EDT Thu Sep 26 2019 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... Hurricane Lorenzo is centered near 15.4N 40.2W at 26/1500 UTC or 920 nm W of the Southernmost Cabo Verde Islands moving WNW at 11 kt. Estimated minimum central pressure is 949 mb. Maximum sustained wind speed is 115 kt with gusts to 140 kt. Numerous strong convection is within 90 nm of the center. Scattered moderate to isolated strong convection is elsewhere from 11N-20N between 33W-45W. Lorenzo is forecast to turn toward the northwest later today, and this motion should continue through Friday. A turn toward the north is expected Friday night and Saturday. Lorenzo is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Additional strengthening is possible today, and fluctuations in intensity are expected tonight through Friday night. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC or www.hurricanes.gov for more details. Tropical Storm Karen is centered near 26.6N 63.3W at 26/1500 UTC or 350 nm SSE of Bermuda moving NNE at 12 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Numerous strong convection is from 25N- 28N between 63W-66W. Scattered moderate to isolated strong convection is elsewhere from 24N-29N between 60W-67W. Karen is forecast to make a slow clockwise loop, ultimately moving westward by early Sunday. Weakening is forecast by the weekend, and Karen is expected to become a remnant low by Sunday. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details. ...A heavy rain event in Central America and Southeastern Mexico... Southwesterly monsoonal flow is pushing abundant moisture from the tropical Pacific Ocean toward Central America. Heavy rainfall is expected in Central America, through the weekend. The greatest threat for heavy rainfall will migrate northwestward to areas from southern Guatemala to southern Mexico, including in the Mexican states of Chiapas, Oaxaca and Guerrero. It is possible that the heavy rains may lead to flash floods and mudslides, especially in areas of mountainous terrain and areas near the Pacific coast. ...TROPICAL WAVES... An east Atlantic tropical wave is along 23W from 14N southward, moving W at 10 kt. Widely scattered moderate convection is from 05N-12N between 18W-27W. A central Atlantic tropical wave is along 53W, from 20N southward, moving W at 10 kt. Scattered showers are within 90 nm of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Senegal near 14N17W to 10N20W to 08N28W. The monsoon trough resumes west of Hurricane Lorenzo near 12N43W to 08N50W. Besides the convection mentioned in the tropical wave section, scattered moderate to isolated strong convection is along the coast of W Africa from 04N-11N between 08W-18W. GULF OF MEXICO... A 1009 mb low is centered over NE Yucatan Peninsula near 19N91W. A surface trough extends NW from the low to the NW Gulf of Mexico near 27N94W. Scattered showers are within 90 nm of the trough. A 1015 mb high is centered over the NE Gulf near 28N85W. 5-10 kt surface winds are noted throughout the Gulf. In the upper levels, an upper level trough is over the NE Gulf. The surface trough will move slowly westward across the southwestern Gulf of Mexico during the next few days before it reaches the northeast coast of Mexico Sat. Elsewhere, relatively weak high pressure centered over the northeast Gulf will be reinforced by stronger high pressure that builds south- southwestward from the western Atlantic Fri through early next week. The resultant gradient will increase winds to fresh speeds over the NE Gulf beginning late Sun. CARIBBEAN SEA... A heavy rainfall event is expected in Central America and southeastern Mexico. Please read the Special Features section above for more details. Radar imagery shows scattered showers over Puerto Rico and the Virgin Islands. A surface trough extends from NE of Jamaica near 19N75W to SW of the Cayman Islands near 18N84W. Scattered moderate convection is within 60 nm of the trough. Further S, scattered moderate to isolated strong convection is over the SW Caribbean from 11N-15N between 77W-82W. A weak pressure pattern allowing for generally light and variable winds and low seas will be replaced by somewhat stronger high pressure that builds southward over the western Atlantic beginning on Fri. This will lead to trades increasing over much of the central and western Caribbean through early next week. A tropical wave will move across the tropical N Atlc on Fri, then through the eastern to central Caribbean this weekend, reaching the western Caribbean early next week. Swells from Hurricane Lorenzo which will east of the region will propagate through the tropical N Atlc and eastern Caribbean passages this weekend into early next week. ATLANTIC OCEAN... Refer to the sections above for details on the tropical wave, Hurricane Lorenzo and T.S. Karen. A 1016 mb high is centered over the W Atlantic near 32N74W. A surface trough extends from the S Bahamas near 24N72W to E Cuba near 20N75W. Isolated moderate convection is within 60 nm of the trough. Of note in the upper levels, an upper level low is centered over the central Bahamas near 23N75W enhancing convection. Another upper level low is centered over the E Atlantic near 31N43W also enhancing convection. Tropical Storm Karen near 26.6N 63.3W 1004 mb at 11 AM EDT moving NNE at 12 kt. Maximum sustained winds 40 kt gusts to 50 kt. Karen will maintain intensity as it moves to near 27.6N 62.5W this evening, then weaken slightly early on Fri near 28.1N 61.1W, reach to near 28.0N 60.4W Fri evening, then weaken to a tropical depression near 27.8N 60.6W Sat morning and reach to near 27.6N 61.9W Sat evening. Karen is forecast to become a remnant low and move to near 27.3N 63.5W Sun morning. Karen will change little in intensity as it moves to near 27.1N 66.5W early on Mon, and continue to near 27.0N 69.0W early on Tue. Meanwhile, high pressure will build down from off the eastern seaboard to the Bahamas this weekend and into early next week tightening the pressure gradient. Winds and seas will increase and build by the end of the weekend into early next week as a result. $$ Formosa