905 AXNT20 KNHC 230555 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 155 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 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...Special Features... Tropical Storm Kirk centered near 9.0N 26.4W at 23/0300 UTC, or 370 nm SSW of the Southernmost Cabo Verde Islands, moving WNW at 14 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Some strengthening is forecast through Sunday, with little change in intensity expected on Monday and Tuesday. Scattered moderate to strong convection is observed from 08N-11N between 24W-31W. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC for more details. Tropical Depression Eleven centered near 13.8N 54.5W at 23/0300 UTC, or 380 nm E of the Windward Islands, moving NW at 3 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. The depression is expected to weaken to a remnant low on Sunday and dissipate by Sunday night east of the Lesser Antilles. Scattered moderate convection is noted from 12N-15N between 51W-55W. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC for more details. Satellite imagery indicates that a frontal non-tropical low pressure system is located about 1000 nm west-southwest of the Azores. Conditions are expected to become conducive for this low to acquire subtropical or tropical characteristics during the next day or so, and a subtropical or tropical cyclone is likely to form by early next week while the low meanders over the central Atlantic Ocean. The system has a medium 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 34N44W to 31N41W to 25N50W to 28N59W. The most recent scatterometer data provide observations of minimal gale-force winds N of 29N and within 60 nm south of the front. Seas of 11 to 13 ft are within the area of these winds. These conditions are expected through Sunday morning. ...TROPICAL WAVES... A tropical wave has its axis along 44W 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. Scattered showers are located near and east of the wave axis from 10N-13N between 38W-44W. A western Caribbean tropical wave has its axis along 87W from 09N-21N, 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. Scattered moderate convection is noted south of 20N between 85W-90W. Moisture associated with this wave will continue to spread inland across Central America through the weekend, enhancing similar convection across this area. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the African coast near 18N16W to 17N21W. It continues west of T.S. Kirk near 06N28W to 05N33W. The ITCZ begins near 05N33W to 05N43W, then resumes near 06N46W to 11N53W. Aside from the convection associated with the tropical wave and cyclones across the area, scattered showers are located along and within 75 nm on either side of the monsoon trough between 30W-36W. ...DISCUSSION... GULF OF MEXICO... An upper-level cyclonic circulation is centered near 28N87W. 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 the far western Caribbean, and a portion of this wave is entering Central America. 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 200 nm south of Bermuda. A surface trough runs through the low from 30N62W to the low near 29N64W to 26N70W. Scattered showers are noted along the trough and near the low. Unfavorable upper-level winds and dry air are expected to limit development tonight and Sunday, 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 1027 mb high centered near 39N20W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA