000 AXNT20 KNHC 060004 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 804 PM EDT Sat Aug 5 2017 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... A tropical wave is in the central Caribbean associated with 1010 mb low near 13N77W. The wave axis extends from 18N77W to the low center to 10N77W and has been moving at 15 kt within the last 24 hours. The wave is in a region of mostly low to moderate vertical wind shear, and is underneath upper level divergent flow, which is supporting numerous heavy showers and scattered tstms from 13N to 18N between 72W and 76W. Similar convection is over Hispaniola with the heaviest convection happening over Haiti. Fresh to near gale force winds was noted in satellite wind data associated with this system that has a medium chance of becoming a tropical cyclone during the next 48 hours. Please read the latest NHC Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more information. ...TROPICAL WAVES... A tropical wave is in the central Atlc associated with a 1010 mb low embedded in the monsoon trough near 09N36W. The wave axis extends from 17N33W to the low center to 07N37W and has been moving at 10-15 kt within the last 24 hours. Moderate to strong vertical wind shear is to the north of the low center where enhanced satellite imagery continue to show intrusion of Saharan dry air and dust to the wave environment. These factors are limiting the convection to scattered heavy showers and isolated tstms from 09N to 13N between 35W and 42W. Scattered showers and isolated tstms are also noted E of the wave axis from 13N to 15N between 31W and 34W. A tropical wave extends is in the central Atlc with axis extending from 19N49W to 10N56W, moving W at 5-10 kt. The wave is in a region of mainly moderate to strong vertical wind shear. However, abundant moisture at the lower levels and a diffluent environment aloft support scattered showers within 90 nm either side of the wave axis. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 12N16W to 13N27W to 09N36W to 11N50W. Aside from convection associated with the tropical waves...scattered heavy showers and tstms are from 07N to 11N between E of 28W. ...DISCUSSION... GULF OF MEXICO... A middle to upper level trough is noted on water vapor imagery over the eastern CONUS with the base of the trough extending over the NE Gulf waters. Diffluent flow aloft generated by the eastern periphery of a broad upper ridge anchored over the Baja California peninsula continue to support scattered to isolated showers over the northern Gulf waters N of 27N. The convection is forecast to lift north overnight as the upper trough moves E over W Atlc waters. Otherwise, a surface ridge extends across the Florida peninsula to the central Gulf being the support for generally fair weather conditions and gentle to light southerly flow. Mostly clear skies and fair conditions are expected to persist with the ridge remaining in place across the basin through Monday. CARIBBEAN SEA... A tropical wave with potential of becoming a tropical cyclone within the next 48 hours moves from the central to the western basin tonight. Heavy showers, tstms and gusty winds are associated with this wave. See the special features section for further details. Heavy showers and tstms associated with the wave extends north to Hispaniola. In the SW Caribbean, a 1010 mb low is located near 10N80W, just at the eastern end of the EPAC monsoon trough. Scattered to isolated showers are being supported by these features S of 12N. This low is forecast to move NW, possibly merging with the low associated with the tropical wave. The wave is expected to bring increased precipitation to Central America and the Yucatan peninsula late tonight through Tuesday. Looking ahead, the arrival of a tropical wave is forecast to impact the Lesser Antilles and surrounding adjacent coastal waters by late Tuesday night into Wednesday bringing increased probabilities of convection and strong winds. ...HISPANIOLA... A tropical wave is in the central Caribbean associated with a 1010 mb. The wave is underneath upper level divergent flow, which is supporting numerous heavy showers and scattered tstms extending N to Hispaniola...the heaviest convection happening over Haiti. Fresh to near gale force winds has been noted in satellite wind data associated with this system that has a medium chance of becoming a tropical cyclone during the next 48 hours. Showers will continue to affect the Island during this time. ATLANTIC OCEAN... The Atlc continues under the influence of a surface ridge anchored by three highs...a 1024 mb high near 28N69W, another near 29N49W and a third 1024 mb high SW of the Azores. No major changes expected within the next 2 days. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos