000 AXNT20 KNHC 040005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT Mon Jul 3 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 over the eastern Atlantic with axis extending from 19N27W to 07N28W, moving westward at 20 kt within the last 24 hours. The wave is in a region of favorable wind shear, however the northern portion of the wave N of 12N is being affected by Saharan dry air also noticed in CIRA LPW imagery. S of 12N, the wave continue embedded in the moist monsoonal flow, which along with middle to upper level diffluence support scattered heavy showers from 09N to 12N between 25W and 31W. A tropical wave is over the central Atlantic with axis extending from 15N34W to 05N34W, moving west at about 5 kt within the last 24 hours. A broad 1011 mb surface low is detached from the wave, and is best satellite estimated position is near 09N33W based on low-level cloud motion and on Ascat data. The atmospheric conditions are similar to the wave east of it already described above. Scattered showers are from 05N to 11N between 30W and 40W. A tropical wave is moving across the Lesser Antilles. Its axis extends from 19N58W to 08N59W. The wave is in a region of unfavorable wind shear and abundant Saharan dry air, which is limiting convection to isolated showers S of 20N between 57W and 63W. A tropical wave is in the central Caribbean with axis extending from 19N70W to 10N72W, moving westward at 10-15 kt. Satellite derived data indicate the wave is in a region of unfavorable wind shear, however the wave is associated with abundant moisture from the surface to 850 mb that along with upper level diffluence support scattered heavy showers and tstms across Hispaniola and southern adjacent waters to 15N. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends from the west coast of Africa near 13N17W and continues along 10N28W to 08N44W. The Intertropical Convergence Zone extends from 08N44W to the coast of Guyana near 07N58W. 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 10N between 16W and 23W. ...DISCUSSION... GULF OF MEXICO... A 1019 mb surface high is centered near 28N86W or in the SW extension of the Atlantic high that reaches the northern and central Gulf. This feature continues to dominate the flow pattern basin-wide where it provides light to gentle variable winds. Otherwise, shallow moisture and upper level diffluence support scattered to isolated heavy showers within 90 nm off the coast of Florida and across the Florida straits. Isolated showers are in the Bay of Campeche. Otherwise, high pressure will remain in place through the next 48 hours, maintaining generally gentle to moderate east-southeast winds throughout except for gentle winds from the west to northwest in direction over the NE Gulf. CARIBBEAN SEA... An upper level cyclonic circulation centered over the NW Caribbean continues to support numerous heavy showers and tstms across Cuba and adjacent waters, including the Yucatan Channel as well as N of 19N W of 75W. Upper level diffluence between this low and a ridge covering the central and eastern Caribbean, along with abundant low level moisture associated with a tropical wave moving across the central Caribbean continue to support scattered heavy showers over Hispaniola, Windward Passage and Mona Passage. Another tropical wave is entering the E Caribbean tonight where it is already generating scattered to isolated showers across the Lesser Antilles. See the tropical waves section above for further details. Otherwise, the eastern segment of the eastern Pacific monsoon trough reaches to NW Colombia and support scattered to isolated heavy showers in the SW basin. The upper level low will slowly move west-northwest across the NW Caribbean through Wednesday while weakening but will bring an increase of moisture along with scattered showers and isolated thunderstorms to the remainder of the NW Caribbean, Cuba and portions of the northern Yucatan Peninsula. Easterly winds will pulse from fresh to strong over the south-central Caribbean through Wednesday. ...HISPANIOLA... Upper level diffluence between an upper level cyclonic circulation centered over the NW Caribbean and a ridge covering the central and eastern Caribbean, along with abundant low level moisture associated with a tropical wave moving across the central Caribbean continue to support scattered heavy showers over Hispaniola, Windward Passage and Mona Passage. Trailing moisture associated with the wave is expected to increase showers and thunderstorms over portions of Hispaniola and the nearby waters through Tuesday. ATLANTIC OCEAN... Three tropical waves are analyzed over the basin. Refer to the Tropical Waves section above for details. A broad upper level low centered over the NW Caribbean support scattered to isolated showers and tstms over the Great Bahama Bank. The remainder of the basin remains under the influence of a broad surface ridge, anchored by a 1029 mb high centered N of the area. This synoptic pattern will change little through Wednesday. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos