000 AXNT20 KNHC 161101 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 701 AM EDT Fri Aug 16 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 0600 UTC surface analysis and satellite imagery through 1040 UTC. ...SPECIAL FEATURES... Potential for Heavy to Extreme Rain/Flooding from southern Mexico to Central America Currently: Scattered moderate to strong rainshowers are in individual areas, from Lake Maracaibo in NW Venezuela, to coastal Colombia from 08N to 10N between 74W and 77W, from the northern coast of Colombia to 13N between 73W and 77W, and within 30 nm to 45 nm on either side of the line that runs from 13N80W to 15N82W to 15N85W, from 210 nm to the ESE of NE Nicaragua to eastern Honduras, and along the coast of Costa Rica. Broken to overcast multilayered clouds and other rainshowers are elsewhere from 16N southward from 70W westward. A large surge of moisture will encompass the areas that extend from northern parts of South America, to Central America, to southern Mexico, 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. The comparatively greatest amounts of rainfall are being forecast for the areas that extend from Panama to Nicaragua, including the offshore waters of those countries in the Caribbean Sea and in the eastern Pacific Ocean. Other areas of rainfall, elsewhere, will cover the areas from NW Venezuela and N Colombia to the Isthmus of Tehuantepec of southern Mexico. Flash floods and mudslides will be the biggest hazards during this event. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 19W/20W from 18N southward, moving W 15 knots. Isolated moderate to locally strong rainshowers are from 06N to 13N between 10W and 20W. An Atlantic Ocean tropical wave is along 51W/52W from 16N southward, moving W 15 to 20 knots. This wave is well depicted in model guidance. Scattered moderate to strong rainshowers are from 09N to 12N between 49W and 56W. Isolated moderate rainshowers are elsewhere from 06N to 13N between 45W and 60W. A Caribbean Sea tropical wave is along 75W from 20N and SE Cuba, southward, moving W 15 to 20 knots. An upper level trough extends from SE Cuba to Jamaica to Honduras. Isolated moderate to locally strong rainshowers cover the waters from 16N northward from Haiti westward. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Senegal near 13N17W, to 11N20W 10N30W 10N40W. The ITCZ continues from 10N40W to 11N46W and 09N50W. Widely scattered moderate to isolated strong rainshowers are within 60 nm to 120 nm on either side of the line that runs from 10N20W to 08N26W 07N37W, and 09N47W. GULF OF MEXICO... A stationary front passes through central Georgia to southern Alabama, southern Mississippi, and central Louisiana. Isolated moderate to locally strong rainshowers are to the east of the line that runs from NW Cuba to 25N95W, to the coastal border of Texas and Louisiana. The combination of a pre-frontal trough in the NE Gulf of Mexico, ahead of a stationary front in the southern U.S.A., and very deep tropical moisture in place, continues to result in scattered showers and thunderstorms in the Gulf waters north of 24N E of about 86W. Some of this activity may contain strong gusty winds causing rough seas. The front will extend from the Florida Panhandle to southeast Texas on Fri morning and then will weaken into a surface trough Sat. Moderate to fresh southwest winds are expected over the NE Gulf ahead of the front and trough. Winds will pulse to fresh in the western Yucatan Peninsula adjacent waters tonight and to fresh to strong beginning on Sat. Otherwise, Atlantic high pressure will build westward across the area early Sat and prevail through Tue. CARIBBEAN SEA... Upper level cyclonic wind flow covers the Caribbean Sea from 14N northward from Puerto Rico westward. A tropical wave is along 75W from 20N southward, moving W 15 to 20 knots. An upper level trough extends from SE Cuba to Jamaica to Honduras. Isolated moderate to locally strong rainshowers cover the waters from 16N northward from Haiti westward. The monsoon trough is along 10N, from 74W in Colombia, to Costa Rica, and beyond NW Costa Rica, into the eastern Pacific Ocean. Please read the SPECIAL FEATURES section, for details about the precipitation and the forecast for heavy to extreme rainfall, and flooding, in Central America. A tropical wave along 75W will move across the rest of the central Caribbean Sea through this afternoon, and across the western Caribbean Sea from tonight through early Saturday night. The passage of the wave, along with high pressure to the north of the area, will continue to support fresh to strong trade winds in the central and southwest sections of the Caribbean Sea through Friday, and in the NW Caribbean Sea on Saturday and Sunday. Fresh to strong winds will resume in the south central basin early on Monday, supported by the passage of a new tropical wave moving across the region. ATLANTIC OCEAN... An upper level trough extends from a 30N20W upper level cyclonic circulation center, to a 28N44W upper level cyclonic circulation center, to a 20N55W upper level cyclonic circulation center, to a Bahamas 25N77W upper level cyclonic circulation center. A surface trough is along 54W/55W from 20N to 29N. Isolated to widely scattered moderate and locally strong rainshowers cover the area from 19N to 30N between 40W and 50W, and in the Bahamas and the Straits of Florida from 27N southward from 70W westward. A surface ridge extends from a 1026 mb high pressure center that is near 34N47W, to 32N53W, to 24N75W, across Florida and through the Straits of Florida to 23N91W in the Gulf of Mexico. A surface ridge, from near 28N65W southwestward to the the Straits of Florida, will remain in place through tonight while a stationary front is located in the southeastern U.S.A. The ridge will begin to slowly lift northward Sat, to north of the area on Sun as a weak trough moves from E to W across the eastern and central forecast waters. The trough will reach the central and NW Bahamas Mon and move inland central and S Florida Tue. The rather light gradient will maintain mainly gentle to moderate winds north of 22N, and moderate to fresh winds south of 22N through most of the period. The wind flow between the front and the ridge will be from the southwest and fresh in speeds over the far NW waters through Sat. Fresh to strong winds are expected between Turks and Caicos and Hispaniola at night through Fri. Strong winds will resume in this area on Monday evening. $$ MT