000 AXNT20 KNHC 041140 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 740 AM 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...SPECIAL FEATURES... A 1009 mb surface low is centered near 09N34W. Scattered moderate and isolated strong convection is located within 120 nm of the center of the low. The low has a large area of cyclonic winds extending about 300 nm from the center. Satellite-derived wind data shows peak winds of near gale force in the southeastern quadrant. The low is expected to move slowly westward today, then move toward the west-northwest at 10 to 15 mph tonight and Wednesday. The system still possesses a high chance of becoming a tropical cyclone during the next 48 hours. ...TROPICAL WAVES... A tropical wave is in the eastern Atlantic with axis near 31W extending from 07N to 18N, moving west at about 20 kt within the last 24 hours. Scattered moderate convection is occurring from 08N to 12N between 29W and 34W. The wave is embedded in a moist monsoonal flow, as seen in the Total Precipitable Water imagery, and extends across the monsoon trough. Little to no surface signature of the wave is apparent from ship and scatterometer observations, though the SUNY-Albany Trough Diagnostics well depict the wave at 700 mb and the TPW shows a distinct maximum in moisture on the east side of the wave axis. A tropical wave is in the central Atlantic with axis near 40W extending from 08N to 20N, moving west at about 15 kt during the last 24 hours. No significant deep convection is occurring in association with the wave, though scattered showers exist within 120 nm of the wave axis south of 12N. This wave had spun off the surface low - described in the Special Features section - which is now to the east of the wave. The wave is only distinguishable in the Trough Diagnostics at 700 mb, with little to no surface circulation. A tropical wave is located along the Lesser Antilles and has been moving westward at about 15 kt. Its axis is near 61W and extends from 08N to 20N. ASCAT scatterometer and surface station observations indicate that the system has a well-defined surface trough. The wave has isolated moderate convection within 120 nm of the wave axis. A tropical wave is in the central Caribbean with axis near 76W extending from 10N to 20N. The wave is moving westward at about 10 to 15 kt. The wave is not readily apparent in either the surface observations, nor in the Trough Diagnostics and there is no active convection associated with it at this time. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends from the west coast of Africa near 14N17W to 08N45W. The Intertropical Convergence Zone extends from 08N45W to the coast of Suriname near 06N54W. Convection observed near the Monsoon Trough and ITCZ is mainly related to tropical waves and the surface low. Refer to the section above for details. Otherwise, widely scattered moderate convection is located from 05N to 11N between 11W and 22W. ...DISCUSSION... GULF OF MEXICO... Weak surface ridging exists across the northern Gulf. A weak surface trough exists in the southwestern Gulf from 23N90W to 18N92W. No deep convection is occurring; however, scattered showers are also occurring in the southeastern Gulf within 120 nm of the Florida peninsula as well as the Florida Straits. Winds are generally 10-20 kt across the Gulf with easterlies in the eastern Gulf and veering to southeasterlies in the western Gulf. Little change in the synoptic pattern is expect in the next couple of days. CARIBBEAN SEA... The moderate pressure gradient across the Caribbean between the Bermuda high to the north and the Colombia low to the south is generally producing 10 to 20 kt tradewind easterlies. The exception is the 25 kt easterlies just north of Colombia and Venezuela. Scattered moderate convection is located over the southwestern Caribbean including portions of Honduras and Nicaragua, in association with the eastern extension of the Northeast Pacific's monsoon trough. An upper low is centered over the northwestern Caribbean near 20N81W, as seen in both the water vapor imagery as well as rawindsonde data from Cancun, Grand Cayman, Key West, Miami, Nassau, and Kingston. This upper low is helping to promote isolated moderate convection near Jamaica and the northwestern Caribbean. The upper low is anticipated to open up to a broad trough in the next day or two, but still helping to promote some enhanced convection. ...HISPANIOLA... Currently there is no deep convection over Hispaniola. Expect diurnal peak in convection to diminish some on this afternoon and early evening before being enhanced again on Wednesday as the moisture associated with the wave over the Lesser Antilles reaches Hispaniola. ATLANTIC OCEAN... Two tropical waves are analyzed over the basin. Refer to the Tropical Waves section above for their details. Also a surface low is detailed in the Special Features section. A large 1031 mb Bermuda/Azores high centered north of the area near 36N41W is dominating the weather across the tropical north Atlantic. Away from the surface low described above, winds generally are 10 to 20 kt across the basin. This synoptic pattern will change little through Wednesday. For additional information please visit http://www.hurricanes.gov/marine $$ Landsea