837 AXNT20 KNHC 170552 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 152 AM EDT Tue Jul 17 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... SW Caribbean Sea gale warning: A strong surface pressure gradient between the central Atlantic and SW Caribbean will produce strong to near gale force NE to E strong winds near the coast of Colombia from 11N to 14N between 69W and 77W for the next 48 hours. A gale is forecast to start 19/0000 UTC from 11N to 12.5N between 74W and 76W with seas 11-14 ft. Please read the High Seas Forecast, under the AWIPS/WMO headers HSFAT2/FZNT02 KNHC, for more details. ...TROPICAL WAVES... A tropical wave is over W Africa along 14W from 03N-15N, moving W at 15 kt. A well defined 700 mb trough is noted together with an inverted-V convection signature. Widely scattered moderate convection is from 07N-15N between 08W-18W. Saharan dust is noted on GOES-16 imagery behind and around this tropical wave. A central Atlantic tropical wave extends from 20N41W to 05N45W, moving westward at 15-20 kt. The wave is depicted on GOES-16 RGB imagery as having a rather broad inverted-V shape envelope of broken to overcast stratocumulus clouds from 09N-22N between 38W- 53W. Scattered moderate convection is from 05N-09N between 40W- 46W. The GOES-16 RGB images of the far eastern Atlantic are depicting yet another massive plume of Saharan dry air and associated dust following in behind the wave from 09N-27N east of 36W to well inland of W Africa. A tropical wave over the central Caribbean extends from Hispaniola near 20N71W to N Colombia near 07N74W, moving westward at 20 kt. This wave has Saharan dust following the wave axis as observed in GOES-16 satellite imagery. Scattered moderate convection is over W Hispaniola and over N Colombia. A tropical wave over the Yucatan Peninsula and Guatemala is along 89W S of 20N, moving westward at 10-15 kt. Scattered moderate isolated strong convection is over the Yucatan Peninsula and Central America from Guatemala to Panama. This wave will move west of the area and into the eastern Pacific late Tue. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from W Africa near 16N17W to 07N25W to 07N30W. The ITCZ continues from 07N30W to 09N40W to 09N44W. The ITCZ continues W of a tropiical wave near 08N46W to South America near 06N54W. Widely scattered moderate convection is from 06N-10N between 18W-23W. Isolated moderate convection is from 06N-08N between 25W-36W. ...DISCUSSION... GULF OF MEXICO... A 1019 mb high centered over the central gulf waters near 25N87W. Light to moderate anticyclonic flow are over the gulf waters. Current NWS mosaic radar shows scattered moderate to isolated strong convection over the northern gulf north of 28N and E of 92W. Similar convection is over the N Florida Peninsula. Expect high pressure to prevail across the northern gulf waters through Thu. A surface trough will move westward off the Yucatan Peninsula each evening through Thu, enhancing nocturnal winds over the eastern section of the SW Gulf. CARIBBEAN SEA... Please read the Special Features section for details about pulsing gale force winds near the coast of Colombia. Aside from the tropical waves mentioned above, an upper level low is noted on water vapor imagery just to the south of the Yucatan Channel. Mainly fresh E winds will continue over the central Caribbean Sea and strong NE-E winds will be over the SW and S central sections of the Caribbean, through Thu. ATLANTIC OCEAN... A weak surface trough over the W Atlantic extends from 32N60W to 29N67W. Scattered showers are within 60 nm of the trough. This trough will slowly weaken Tue as the supporting upper trough lifts to the NE away from it. High pressure will build in the wake of the trough. A large area of Saharan Air Layer (SAL) dust that is currently over the central Atlantic from 08N-24N and between 45W-60W will continue to translate westward through the rest of the week. A weaker area of dust from 09N-27N between the SE Bahamas and 60W is also moving westward. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa