000 AXNT20 KNHC 052357 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 757 PM EDT Thu Sep 5 2019 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 2320 UTC. ...SPECIAL FEATURES... Hurricane Dorian is centered near 33.1N 78.5W at 05/2100 UTC or 40 nm SSE of Myrtle Beach, South Carolina and about 70 nm SSW of Wilmington, NC. Dorian is moving NE at 7 kt with a minimum central pressure of 960 mb. The maximum sustained wind speed is 90 kt with gusts to 110 kt. Numerous moderate with embedded scattered strong convection is seen within 150 nm N semicircle and 80 nm S semicircle. Scattered moderate to isolated strong convection is seen elsewhere within 300 nm NE quad, 160 nm SE quad, 150 nm SW quad, 200 nm NW quad. Currently, the eye of Dorian is still just off the North and South Carolina coast and approaching Bald Head Island, NC. Dorian will increase in forward speed through Saturday. It is expected to move near or over the coast of North Carolina tonight and Friday. The center should move to the southeast of extreme southeastern New England Friday night and Saturday morning, and approach Nova Scotia later Saturday or Saturday night. Slow weakening is expected during the next few days. However, Dorian is expected to remain a powerful hurricane as the center moves near the coasts of South and North Carolina. Dorian is forecast to become a hurricane-force post-tropical cyclone by Saturday night as it approaches Nova Scotia. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC or the website hurricanes.gov for more details. Tropical Storm Gabrielle is centered near 23.4N 35.9W at 05/2100 UTC or 800 nm NW of the Cabo Verde Islands and about 990 nm SSW of the Azores. Gabrielle is moving NW at 9 kt with an estimated minimum central pressure of 1002 mb. The maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered moderate convection is seen on the north side only, from 26N-30N between 31W-37W. A faster motion toward the northwest is expected for the next several days. Little change in strength will likely occur during the next day or two. Slow strengthening is forecast to occur over the weekend. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC or the website hurricanes.gov for more details. ...TROPICAL WAVES... An eastern Atlantic tropical wave extends its axis along 21W S of 19N, moving W at 10-15 kt. Scattered moderate showers with embedded thunderstorms are seen from 13N-16N between 22W-24W. Gradual development of this system is possible and a tropical depression could form while it moves westward across the tropical Atlantic Ocean through early next week. Enhanced rainfall is possible across the Cabo Verde Islands through early Friday as the disturbance moves through the region. The chance of tropical cyclone formation during the next 48 hours is low. An Atlantic tropical wave extends its axis along 58W S of 20N, moving W at 10-15 kt. It was not discernible on the 1800 UTC map but based on model data and surface features it will be added on the 0000 UTC map. Scattered showers are located about 200 nm within Leeward Islands from 15N- 21N between 51W- 57W. Only slow development of this disturbance, if any, is expected during the next couple of days while it moves slowly northwestward. The chance of tropical cyclone formation during the next 48 hours is low. A central Caribbean tropical wave extends its axis along 70W S of 17N, moving W at 15 kt. Scattered moderate to strong convection continues to be noted over W Venezuela and E Colombia from 08N- 12N between 68W-74W. Scattered showers are also seen over eastern portions of the ABC Islands. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Mauritania near 19N16W to 10N26W to 11N47W. The ITCZ is from 11N52W to 13N63W. Aside from the convection mentioned in the section above, scattered moderate showers with isolated thunderstorms are seen from 04N- 12N between 25W- 48W. Isolated showers and thunderstorms are seen along the ITCZ 09N-12N between 51W-59W. GULF OF MEXICO... Scattered showers and thunderstorms are seen in the central and western Gulf of Mexico from 23N-27N and west of 85W. Otherwise, drier air is over the northern Gulf of Mexico, with a 1018 mb surface high centered near 28N94W. The latest ASCAT pass shows moderate W winds over the far NE Gulf of Mexico, with gentle winds elsewhere in the basin. High pres will extend from NW to SE across the basin producing gentle to moderate winds through the weekend, then will extend from E to W from the NE Gulf early next week allowing for return flow and a slight increase in winds. CARIBBEAN SEA... Refer to the section above for details on the tropical waves moving across the basin. An upper-level trough over the western Caribbean is aiding in scattered moderate convection across this area from 82W-86W between 79W-86W. Some isolated thunderstorms are moving off of SW Puerto Rico into adjacent waters. Otherwise, fair weather prevails in the central and eastern Caribbean due to upper level ridging. The latest ASCAT pass shows strong trades in the south-central Caribbean from 11N-15N between 73.5W-77W. Otherwise, moderate to fresh trades are in the central Caribbean with light to gentle trades elsewhere. Weak Atlantic ridge extends from the central Atlantic to the SE Bahamas. Fresh to strong tradewinds will pulse in the S central Caribbean tonight into early Friday, and then again early next week. Otherwise, mainly moderate to fresh tradewinds are expected. ATLANTIC OCEAN... Refer to the sections above for details on Dorian, Gabrielle and two tropical waves moving across the basin. Scattered showers are still moving across the western Atlantic, N of 29N and W of 76W. Isolated thunderstorms are seen moving off of Cuba and into the northern Bahamas. Scattered showers and thunderstorms are moving south into the central Atlantic due to a small area of low pressure located a few hundred miles northeast of Bermuda. This activity is noted N of 26N between 56W-65W. A trough is extending from the low near 35N60W to 28N63W. This system has become poorly defined and significant development is not anticipated. An upper level low is seen in the central Atlantic with a surface trough analyzed from 23N41W to 27N47W. Scattered showers and thunderstorms are associated with this trough from 24N-30N between 43W-48W. Another surface trough is noted 200 nm east of the Lesser Antilles, analyzed from 16N57W to 22N55W. Scattered showers and thunderstorms are seen from 16N-23N between 49W-57W. Hurricane Dorian will produce large northerly swell over the SW N Atlantic through the weekend. This swell continues to produce high seas within the Gulfstream offshore of central and SE Florida. Much more tranquil marine conditions are forecast by early next week. $$ AKR