000 AXNT20 KNHC 150604 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 204 AM EDT Tue Aug 15 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Hurricane Gert is centered near 31.2N 72.3W at 15/0300 UTC or about 385 nm W of Bermuda moving N at 7 kt. Estimated minimum central pressure is 986 mb. Maximum sustained wind speed is 65 kt with gusts to 80 kt. Numerous moderate convection is from 30N- 32N between 71W-74W. Scattered moderate convection is elsewhere from 28N-34N between 71W-74W. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details. ...TROPICAL WAVES... A tropical wave is W of the Cape Verde islands with axis extending from 24N24W to 11N27W, moving W at 10 kt. The wave is in a region of low vertical wind shear, however intrusion of Saharan dry air and dust to the wave environment limit the convection. Shallow moisture confined to the vicinity of the monsoon trough and upper level diffluent wind support scattered moderate convection from 10N to 14N between 28W and 33W. Slow development of this system is anticipated during the next day or two, but conditions are forecast to become a little more conducive for tropical cyclone formation by later in the week while the system moves westward over the tropical Atlantic. A tropical wave is in the central Atlc with axis extending from 23N45W to 08N49W, moving W at 25 kt. The wave is entering a region of moderate to strong vertical wind shear and is being severely affected by extensive Saharan dry air and dust, which is hindering convection at the time. A tropical wave is in the E Caribbean with axis extending from 21N63W to 10N66W, moving W at 25 kt. The wave is in a region of strong vertical wind shear and dry air subsidence, which is hindering deep convection at the time. Shallow moisture observed in CIRA LPW imagery and upper level diffluent flow ahead of the wave axis in the N-central Caribbean support isolated showers over northern Puerto Rico and adjacent waters as well as the Mona Passage. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the coast of W Africa near 15N16W to 12N37W to 08N49W. The Intertropical Convergence Zone axis extends from 08N52W to the coast of Venezuela near 08N60W. Numerous heavy showers and scattered tstms are coming off the W African coast associated with the next tropical wave. The convection extends from 06N to 13N E of 21W. Scattered moderate convection is from 07N to 16N between 30W and 46W associated with a 1011 mb low located near 12N37W. ...DISCUSSION... GULF OF MEXICO... Weak surface ridging prevails across the basin, which along with dry air subsidence support mainly fair weather conditions. A broad upper level low is centered just N of the Yucatan Peninsula, which supports isolated showers there and in the Yucatan Channel. Diffluent flow in the NW periphery of the low support similar shower activity off the SE coast of Louisiana, Mississippi and Alabama. Winds are gentle to moderate and from the S-SE in the western half of the basin and light variable elsewhere. The ridge will remain in place across the Gulf waters the next couple of days. A surface trough will develop each evening across the Yucatan Peninsula shifting W to the Bay of Campeche during the overnight hours. Locally higher winds can be expected west of the trough axis. CARIBBEAN SEA... A tropical wave is moving through the eastern Caribbean. Please see section above. The tropical wave will propagate westward across Puerto Rico early this morning, then will move over central Caribbean waters early on Wednesday. Isolated showers are occurring ahead of the wave over northern Puerto Rico and adjacent waters, the Mona Passage and Hispaniola, but mainly due to shallow moisture and a diffluent wind environment aloft. A broad upper level low centered just N of the Yucatan Peninsula support isolated showers in the Yucatan Channel extending to NW Caribbean waters N of 17N W of 81W. Otherwise, fresh to near gale force winds are in the south-central basin forecast to continue through Thursday. ...HISPANIOLA... An upper level low over the central Atlc will drift WSW to the north and across the Island over the next couple of days. This low aloft along with the passage of a tropical wave will support scattered to isolated showers over the Island and adjacent waters through Thursday. ATLANTIC OCEAN... Scattered showers are NE of the Bahamas between 70W-76W associated with the rainbands of Hurricane Gert centered north of the area. See Special features. Otherwise, the remainder basin generally N of 20N is under the influence of the Azores high. For information about tropical waves, see section above. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos