000 AXNT20 KNHC 030001 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 801 PM EDT Sun Jul 2 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. ...TROPICAL WAVES... A tropical wave is in the E Atlc with axis extending from 15N19W to 06N19W, moving west at about 5 kt within the last 24 hours. The wave is entrenched in a very moist monsoonal flow that has become well established from over inland Africa to well offshore the coast of Africa, and has overtaken some of the dry air earlier noted north and west of the wave. The wave is in a region of favorable wind shear, and middle to upper level diffluence that support scattered to isolated heavy showers from 06N to 16N E of 22W. A tropical wave is in the central Atlc with axis extending from 16N31W to 06N33W, moving W at 5 kt within the last 24 hours. Satellite enhanced imagery continue to show Saharan dry air and dust intrusion to the wave environment. CIRA LPW imagery confirm the intrusion of the dry air from the surface to 850 mb. The wave is in a region of neutral to favorable wind shear, and middle to upper level diffluence that support isolated showers from 07N to 15N between 30W and 35W. A tropical wave is in the E Caribbean with axis extending from southern Puerto Rico near 18N66W to inland Venezuela near 07N67W. A very moist environment is associated with this wave S of 16N according to CIRA LPW imagery while neutral to favorable wind shear is in this same region. These two factors support scattered to isolated showers from 13N to 16N between 63W and 72W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends from the west coast of Africa near 12N16W to 10N22W to 09N30W to 08N36W. The Intertropical Convergence Zone extends from 09N36W to 05N50W. Convection observed near the Monsoon Trough and ITCZ is mainly related to tropical waves. Refer to the section above for details. Otherwise, numerous heavy showers and isolated tstms are from 06N to 11N between 20W and 31W. ...DISCUSSION... GULF OF MEXICO... A 1021 mb surface high is centered near 28N87W, and is situated on the SW extension of the Atlantic high that reaches to the Gulf. The ridge extends westward from the 1021 mb high to Texas adjacent waters N of 25N. This feature continues to dominate the flow pattern throughout the basin, thus providing light to gentle variable winds in the northern half of the Gulf. A surface trough is in the SW basin along 22N93W to 16N94W, which is supporting scattered to isolated showers in the Bay of Campeche. Light to gentle variable winds are in the vicinity of the trough while easterlies of the same magnitude are in the SE portion of the basin. Little change is expected in the current synoptic pattern through Tuesday. CARIBBEAN SEA... The passage of a tropical wave and an upper level diffluent pattern over northern Central America continue to support isolated showers and tstms over the NW Caribbean. A broad upper level low over Cuba supports the continuation of heavy showers and tstms in the southern and eastern portion of the Island as well as adjacent waters. Upper level divergence between the low over Cuba and a broad upper ridge centered in the E Caribbean continue to support scattered heavy showers and tstms over northern and central Haiti and isolated showers over the NW Dominican Republic. In the SW basin, numerous heavy showers and tstms are over Panama and coastal waters associated with the EPAC monsoon trough. Otherwise, a tropical wave is moving over the eastern portion of the basin supporting showers. See the tropical waves section above for further details. Aside from the areas discussed above, generally fair weather prevails elsewhere. The tropical wave is forecast to move across the rest of the eastern Caribbean through early Monday, then the central Caribbean during the remainder of Monday and through Tuesday. ...HISPANIOLA... Upper level divergence between a broad upper level low over Cuba and a broad upper ridge centered in the E Caribbean continue to support scattered heavy showers and tstms over northern and central Haiti, and isolated showers over the NW Dominican Republic. The atmospheric environment is forecast to become more moist and unstable on Monday as a tropical wave currently over the eastern Caribbean approaches the island. Expect increasing shower and thunderstorms during Monday and through Tuesday. ATLANTIC OCEAN... Two tropical waves are analyzed over the basin. Refer to the Tropical Waves section above for details. A large surface trough over the central Atlantic is analyzed from near 29N46W to 11N48W moving steadily westward around 10 kt. The trough is surrounded by a dry and stable air mass. Only isolated showers are possible in the vicinity of this surface feature. A broad upper level low centered over Cuba support scattered to isolated showers and tstms over the Great Bahama Bank and across the southern-central Bahamas. The remainder of the basin remains under the influence of a broad surface ridge, anchored by a 1029 mb high centered just northeast of the Azores. This synoptic pattern will change little through Tuesday. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos