000 AXNT20 KNHC 041822 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 221 PM EDT Tue Jul 4 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...SPECIAL FEATURES... A 1009 mb surface low is centered near 10N34W. Scattered moderate and isolated strong convection is located in the northeast and southwest quadrants of the low within 360 nm of the center. The low is surrounded by a large area of cyclonic winds extending about 400 nm from the center. The latest satellite-derived wind data shows peak winds of near gale force in the southeastern quadrant. The low is expected to move slowly W today, then move toward the WNW at 10 to 15 mph tonight and Wednesday. The system retains a high chance of becoming a tropical cyclone during the next 48 hours. ...TROPICAL WAVES... A tropical wave over the eastern Atlantic has an axis extending from 07N32W to 18N32W, moving west at about 20 kt during the last 24 hours. The wave is embedded in a moist monsoonal flow, as seen in the Total Precipitable Water imagery, and extends across the monsoon trough. This wave is reflected by a surface trough in satellite derived wind data as well as initial model 700 mb wind fields. No significant deep convection is occurring in association with this wave. A tropical wave over the central Atlantic has an axis extending from 08N44W to 20N39W, moving west at about 20 kt during the last 24 hours. This wave had spun off the surface low currently to the east of the wave axis. The convection formerly associated with this wave has consolidated around the surface low. This low is described in the Special Features section. The wave exhibits a modest signature in initial model 700 mb wind fields. A tropical wave located over the far eastern Caribbean has an axis reaching from 10N65W to 21N62W, moving west at around 15 kt during the past 24 hours. Satellite-derived wind data and surface station observations both show the wave has a well defined surface trough. The wave has scattered moderate and isolated convection from 19N to 21N between 60W and 63W. A tropical wave over the western Caribbean has an axis running from 10N80W to 19N80W. The wave is moving westward at about 20 kt. The wave only exhibits subtle troughing in surface observations and initial 700 mb model fields. Scattered moderate and isolated strong convection is present within 120 nm either side of a line from 13N79W to 18N86W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends from Senegal on the west coast of Africa near 14N16W to low pres 1009 mb near 10N34W to 08N42W. The Intertropical Convergence Zone extends from 09N46W to just N of the coast of Suriname near 07N55W. Convection observed near the Monsoon Trough and ITCZ is associated with tropical waves and the surface low. Refer to the Tropical Waves and Special Features sections above for details. Otherwise, widely scattered moderate convection is located from 05N to 09N between 10W and 18W. ...DISCUSSION... GULF OF MEXICO... Weak surface ridging crosses the northern Gulf from central Florida to the Texas Coastal Bend. A weak surface trough extends into northern Florida from 29N85W. No deep convection is currently associated with this trough. Winds over the Gulf generally run between 10 and 20 kt across the Gulf. Easterlies over the eastern Gulf veering to southeasterlies over the western Gulf. Little change in this pattern is expected during the next couple of days. CARIBBEAN SEA... The moderate pressure gradient over the Caribbean between the Bermuda high to the north and the Colombia low to the south is maintaining moderate to fresh tradewinds over the basin. The exception is fresh to strong easterlies north of Colombia and Venezuela. Convection over the SW Caribbean in the vicinity of Honduras and Nicaragua appears to be associated with with the eastern extension of the NE Pacific monsoon trough and a tropical wave mentioned in the Tropical Waves section. Water vapor satellite imagery indicates an upper-level low is centered over the NW Caribbean just S of Cuba near 21N79W. This low is interacting with the tropical wave to trigger convection over the western Caribbean. The upper-level low is expected to weaken and move NW by Thu, which should allow convection in this area to decrease. ...HISPANIOLA... Currently there is no deep convection over Hispaniola as an upper- level ridge resides overhead. Expect convection to increase on Wednesday as the moisture associated with the wave over the Lesser Antilles arrives. ATLANTIC OCEAN... Two tropical waves are analyzed over the basin. Refer to the Tropical Waves section above for details. Also a surface low is described in the Special Features section. A large 1030 mb high is centered SW of the Azores near 35N41W. The high continues to dominate the weather across the tropical north Atlantic. To the south of the high and away from the surface low described above, moderate to fresh trade winds prevail across the basin. This synoptic pattern will change little through Wednesday night. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy