788 AXNT20 KNHC 231207 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 807 AM EDT Sun Sep 23 2018 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... Tropical Storm Kirk centered near 9.1N 28.0W at 23/0900 UTC or 400 nm SSW of the Southernmost Cabo Verde Islands moving W at 16 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Some strengthening is forecast during the next day or two. Weakening is likely during the middle to latter part of the week. Scattered moderate to strong convection is from 08N-12N between 25W-32W. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC for more details. Tropical Depression Eleven centered near 14.5N 55.0W at 23/0900 UTC or 360 nm ENE of the Windward Islands moving NW at 5 kt. Estimated minimum central pressure is 1009 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. A slow west-northwest to northwest motion is expected until the system dissipates in a day or so. Scattered moderate convection is noted from 12N-15N between 52W-55W. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC for more details. Satellite imagery indicates that a non-tropical low pressure system currently located about 1000 miles west-southwest of the Azores is producing gale-force winds with some associated showers and thunderstorms. Conditions appear conducive for this system to acquire some subtropical or tropical characteristics during the next day or so while meandering over the central Atlantic Ocean, and the low could become a subtropical or tropical cyclone before it is overtaken and absorbed by a cold front late Tuesday or Wednesday. The system has a high chance of tropical cyclone formation within the next 48 hours. Please refer to the latest Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more information. A cold front extends from a 1004 mb low pressure located N of the area near 34N46W to 31N40W to 24N50W to 27N60W. The most recent scatterometer data provide observations of minimal gale-force winds N of 30N within 60 nm E of front with seas 11-13 ft. These conditions are expected to decrease below gale shortly at 23/1200 UTC. ...TROPICAL WAVES... A tropical wave has its axis along 46W from 03N-16N and is moving west at 10-15 kt. The wave corresponds nicely with a maximum in TPW imagery. Model analyses depict an associated 700 mb trough along 44W. Isolated moderate convection is located from 03N-14N between 40W-50W. A Central American tropical wave has its axis along 89W from 08N- 20N, moving west around 10 kt. The 700 mb trough associated with this wave is well depicted in model guidance, and TPW imagery shows abundant moisture in its environment. Widely scattered moderate convection is south of 20N between 85W-92W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the African coast near 13N17W to 10N20W. It continues west of T.S. Kirk near 06N30W to 05N34W. The ITCZ begins near 05N34W to 04N40W to 05N44W, then resumes near 05N48W to the South American coast near 04N51W. Aside from the convection associated with the tropical wave and cyclones across the area, widely scattered moderate convection is located S of 75 the monsoon from 04N-11N between 10W-18W. ...DISCUSSION... GULF OF MEXICO... An upper-level cyclonic circulation is centered near 25N87W. This feature is enhancing convection across the eastern Gulf waters mainly along 84W. To the west, a surface trough is analyzed along 91W from 24N-29N. Scattered showers are noted along the trough. A cold front is entering the northwest Gulf enhancing convection north of 25N and west of 95W. This front is likely to stall and dissipate today. Gentle to moderate E to SE winds and seas 3 ft or less will prevail across most of the Gulf of Mexico through the middle of next week. A surface trough will develop over the Yucatan peninsula each evening, shift W over the SW Gulf each night, then dissipate by morning. Moderate to fresh winds will accompany this trough. CARIBBEAN SEA... A tropical wave is moving across Central America, and a portion of the wave's convection is over the W Caribbean. Please see the Tropical Waves section for more details. The eastern Pacific monsoon trough combined with diffluence aloft continues to enhance convection over portions of Panama and the waters of the southwest Caribbean from the coasts of Panama and Costa Rica northward to 13N and eastward to 78W. Plenty of moisture will persist over the extreme southwest Caribbean, Panama and Costa Rica through the weekend. Elsewhere, fresh to strong winds prevail over the central Caribbean. These winds will diminish across most of the basin by tonight. ATLANTIC OCEAN... Currently, there are two tropical cyclones and a tropical wave between the west coast of Africa and the Lesser Antilles. Please see the Special Features and Tropical Waves sections for more details. A broad 1010 mb low is centered near 28N67W. A surface trough runs through the low from 30N64W to the low center to 26N72W. Scattered showers are noted along the trough and near the low. Unfavorable upper-level winds and dry air are expected to limit development today, but conditions could become more conducive for some development of this system on Monday or Tuesday while it moves westward and west-northwestward over the southwestern Atlantic Ocean. By the middle of next week, strong upper-level winds are likely to limit additional development as the system turns northward and moves closer to the southeastern coast of the United States. This feature has a low chance of tropical cyclone formation during the next 48 hours. The remainder of the basin is under the influence of a surface ridge, anchored by a 1028 mb high centered near 40N21W. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa