000 AXNT20 KNHC 040600 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 200 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 0000 UTC surface analysis and satellite imagery through 0600 UTC. ...SPECIAL FEATURES... A 1010 mb surface low is centered near 09N33W. Scattered moderate and isolated strong convection is located within 120 nm in the western semi-circle of the low. The low has a large area of cyclonic winds extending about 300 nm in diameter and ASCAT scatterometer data showed peak winds of near gale in the southeastern quadrant. The low is expected to move slowly westward today, and then move toward the west-northwest at 10 to 15 mph by tonight and on Wednesday. The system has 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 30W 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 28W and 33W. 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 37W extending from 05N to 15N, moving west at about 10 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 well-defined tropical wave is locate along the Lesser Antilles and has been moving westward at about 15 to 20 kt. Its axis is near 62W and extends from 10N to 20N. However, scatterometer data arriving after the 00 UTC analysis was completed shows that the wave axis may be closer to 59W. The wave has isolated moderate convection within 120 nm of the wave axis. A tropical wave is in the central Caribbean with axis near 74W 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 12N16W to 08N44W. The Intertropical Convergence Zone extends from 08N45W to the coast of Guyana near 08N59W. 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, scattered moderate convection is located from 06N to 10N between 16W and 23W. ...DISCUSSION... GULF OF MEXICO... A 1019 mb surface high is centered over the northeastern Gulf near 28N87W. A weak surface trough exists over the Yucatan of Mexico for 22N88W to 16N93W. Scattered moderate convection is occurring mainly over Mexico within 120 nm of the trough axis. 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. Isolated 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 over Cuba, the northwestern Bahamas, 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... During the afternoon and early evening, scattered moderate convection occurred over central Haiti and Dominican Republic. This is currently waning. Expect convection to diminish some on Tuesday 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 details. A large Bermuda/Azores high centered north of the area near 35N41W 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