000 AXNT20 KNHC 150605 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 AM EDT Thu Aug 15 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 0000 UTC surface analysis and satellite imagery through 0540 UTC. ...SPECIAL FEATURES... A large surge of moisture will continue across Panama, Costa Rica, and southern Nicaragua during the next 24 to 36 hours. Environmental conditions remain highly favorable for heavy rains to continue to accumulate, with higher localized totals near strong topographical forcing. Costa Rica has received nearly 7 inches of rainfall during the last 24 hours, with 2-4" of additional rain in the last 6 hours mostly on the north Caribbean side of the country. By Friday: the focus of the heavy rainfall will shift northward, to Nicaragua, El Salvador, southern Honduras/Guatemala and southern Chiapas in Mexico. Flash floods and mudslides will be the biggest hazard during this event. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 42W/43W, from 12N southward, is moving westward 10 to 15 knots. This wave is well depicted in model guidance. Monsoon trough-related precipitation is nearby. A Caribbean Sea tropical wave is along 67W/68W, from the Mona Passage southward to Venezuela, is moving westward 15 to 20 knots. Dry Saharan air prevails in the wave's environment inhibiting significant precipitation at this time. A Caribbean Sea tropical wave is along 86W/87W, from 19N in the NW corner of the Caribbean Sea, across Honduras and beyond Nicaragua, moving westward 10 knots. This feature is helping to enhance the precipitation that is near the monsoon trough, in parts of Central America and adjacent waters S of 15N between 80W and 90W. Isolated moderate rainshowers are in NE Nicaragua. The SPECIAL FEATURES section gives more details about a heavy rain event that is happening now and for the next day or two, from Colombia to Nicaragua, in Central America. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Mauritania near 19N16W, to 12N25W and 08N45W. The ITCZ continues from 08N45W, to NW French Guiana near 05N54W. Isolated moderate to locally strong rainshowers are within 60 nm to 120 nm on either side of the line that extends from 08N14W to 07N26W 09N31W 07N42W 08N47W 10N60W. Other isolated moderate rainshowers are from 12N southward from 60W eastward. GULF OF MEXICO... Upper level anticyclonic wind flow spans the area. The GFS model shows a 700 mb trough that passes through the Florida Panhandle toward the SW corner of the Gulf of Mexico. The GFS 500 mb pattern consists of broad anticyclonic wind flow from 90W westward, and a trough from the western coast of Florida along 26N northward. A surface trough is in the Florida Panhandle. A stationary front is inland, passing through South Carolina to southern Mississippi and central Louisiana. Widely scattered moderate to isolated strong rainshowers are in the Gulf of Mexico from 26N northward between Florida and 90W. Isolated moderate rainshowers are in Mexico, from 20N southward between 90W and 100W. The frontal boundary that is in the south and southeast U.S.A. will reach the northern waters of the Gulf of Mexico on Thursday morning. The front will stall on Friday, before moving to the north of the area on Saturday morning. Scattered moderate rainshowers and thunderstorms will continue in the northern half of the basin through Saturday. Moderate to fresh SW winds are expected in the NE waters from Thursday through Saturday, associated with the front. The wind speeds will pulse to fresh in the western Yucatan Peninsula adjacent waters each evening, associated with the diurnal surface trough. Surface high pressure will establish itself elsewhere in the region on Saturday, and prevail through Monday. CARIBBEAN SEA... An upper level trough extends from a cyclonic circulation center, that is just to the north of the SE Bahamas, toward northern coastal areas of Colombia. Isolated moderate rainshowers cover the areas that are from 15N northward from Haiti westward. The monsoon trough is along 09N/10N from 74W in Colombia, beyond 86W in the eastern Pacific Ocean. Numerous strong rainshowers from 04N to 10N between 75W and 80W, in Colombia and Panama, in adjacent coastal waters of the SW Caribbean Sea, and in the eastern Pacific Ocean, and in the Caribbean Sea from 10N to 12N between 78W and 82W. Broken to overcast multilayered clouds and isolated moderate rainshowers are from 17N southward between 60W and 70W. The 87W tropical wave will move out of the western Caribbean Sea tonight. The second tropical wave, currently along 67W, will move across the central Caribbean Sea on Thursday, and the western Caribbean Sea on Friday and Saturday. The passage of the second wave, along with high pressure to the north of the area, will continue to support fresh to strong winds in the central and southwest Caribbean Sea through Fri night, and in the NW Caribbean Sea on Saturday and Sunday. Fresh to strong winds will resume in the south central basin on Monday evening, supported by a new tropical wave that will move across the region. No tropical cyclone activity is expected during the next several days. ATLANTIC OCEAN... An upper level trough extends from an upper level cyclonic circulation center that is between the Canary Islands and the Madeira Archipelago, to a 27N39W cyclonic circulation center, to a 22N51W cyclonic circulation center, to a third cyclonic circulation center that is just to the north of the SE Bahamas. The comparatively greatest concentration of isolated moderate to locally strong rainshowers is from 23N to 32N between 42W and 51W, and from 23N to 26N between 74W and 76W. Other rainshowers possible, from 20N northward from Florida eastward, and mostly on the northern side of the trough. A surface ridge extends from a 1027 mb high pressure center that is near 34N47W, to 30N57W, to SE Cuba. A surface ridge, extending from the Bermuda High, will persist across the forecast waters through Monday. This pattern will maintain mainly gentle to moderate winds north of 22N, and moderate to fresh winds south of 22N through most of the period. Strong winds are expected between the Turks and Caicos Islands and Hispaniola at night through Friday. No tropical cyclone activity is expected for the next several days. $$ MT