000 AXNT20 KNHC 051129 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 729 AM EDT Wed Jul 5 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 11N35W. A tropical wave extends through the low from 06N to 20N. Scattered moderate and isolated strong convection is located within 120 nm in low's western semicircle. No observations of the peak winds have been available in the last several hours, though it is likely that the strongest winds are 25-30 kt. Environmental conditions remain favorable for a tropical cyclone to form within the next day or two while the low moves westward or west-northwestward at 10 to 15 mph across the tropical Atlantic. The system retains a high chance of becoming a tropical cyclone during the next 48 hours. ...TROPICAL WAVES... A tropical wave over the central Atlantic has an axis near 52W extending from about 07N to 22N, moving west at about 20 kt during the last 24 hours. This wave had spun off the surface low now well to the east of the wave axis. Isolated moderate convection is noted within 180 nm of the axis south of 12N. The wave has little to no surface circulation and has no signature in the Total Precipitable Water imagery, though it is readily apparent at 700 mb in the SUNY-Albany Trough Diagnostics. A tropical wave located over the eastern Caribbean has an axis near 68W extending from about 10N to 21N, moving west at around 15 kt during the past 24 hours. ASCAT scatterometer and surface station observations both show the wave has a well-defined surface trough. Rawindsondes at Santo Domingo and San Juan as well as the Trough Diagnostics suggest that the 700 mb wave axis may be slightly westward of the surface trough. Scattered moderate convection prevails within 180 nm of the axis north of 15N. A tropical wave over the western Caribbean and Honduras has an axis near 87W from 10N to 21N. The wave is moving westward at about 15-20 kt. The wave can be seen in as a trough in both surface observations and in 700 mb winds from Cayman Island, Cancun, Merida, and Belize City rawindsondes. Scattered moderate and isolated strong convection is located within 120 nm of the axis north of 15N as well as from 15N-20N between 81W-85W. The combination of a tropical upper tropospheric trough extending east-west at 23N and this wave is helping to enhance this convection. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the Senegal coast at 14N17W to 06N24W, with a break, and then resuming at 12N30W extending across the Special Feature low near 11N35W, then to 09N40W. The Intertropical Convergence Zone then extends from 09N40W to 09N52W. Aside from the convection related to the Special Feature's low/wave, scattered moderate isolated strong convection is observed from 00N to 07N between 35W and 42W as well as north of 05N and east of 17W to the West African coast. ...DISCUSSION... GULF OF MEXICO... A weak surface ridge extends across the northern Gulf. A tropical upper tropospheric trough extends east-west at 23N. Isolated showers in the southeastern Gulf are being enhanced by this upper low. Scatterometer, ship, and buoy observation indicate that the surface winds across the Gulf are light to moderate breeze. Little change in this pattern is expected during the next couple of days. CARIBBEAN SEA... Two tropical waves are moving across the Caribbean. Refer to the section above for details. The convection over the western Caribbean is related to the combination to the westernmost tropical wave along 87W and a tropical upper tropospheric trough centered along 23N. The moderate pressure gradient over the Caribbean between the Bermuda high to the north and the Colombian low to the south is maintaining gentle to fresh tradewinds over the basin, except over the waters north of Colombia and Venezuela where fresh to strong easterlies are pulsing every night lasting through the early morning hours. Expect the upper-level trough to weaken through Thursday, which should allow convection in this area to decrease. Little change is expected in the surface winds during the next couple of days. ...HISPANIOLA... Scattered showers are occurring over eastern Dominican Republic early this morning. Expect convection - especially late afternoon and early evening enhanced by diurnal heating and orographic lifting - to increase on Wednesday and Thursday as the moisture associated with a tropical wave approaches from the east. ATLANTIC OCEAN... Two tropical waves are analyzed over the basin. Refer to the Special Features and Tropical Waves sections above for details. Aside from the convection associated with surface low and monsoon trough described above, no other significant convection is currently occurring. A broad 1030 mb surface high is centered north of our area near 35N40W. 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 the next couple of days. For additional information please visit http://www.hurricanes.gov/marine $$ Landsea