AXNT20 KNHC 251557

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1156 AM EDT Mon Sep 25 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 1800 UTC.


Hurricane Maria is centered near 31.2N 72.9W at 25/1500 UTC or about 270 nm south-southeast of Cape Hatteras North Carolina, moving north at 6 kt. Minimum central pressure is 963 mb. Maximum sustained winds are 70 kt with gusts to 85 kt. Scattered moderate convection is within 180 nm in the northeast semicircle from the center. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.

Hurricane Lee is centered near 30.8N 49.9W at 25/1500 UTC or about 770 nm east of Bermuda. Lee drifting slowly to the south- southwest. Estimated minimum central pressure is 980 mb. Maximum sustained winds are 80 kt with gusts to 100 kt. Scattered moderate convection within 90 nm of the center. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.


A tropical wave extends along 33W/34W from 07N to 20N, moving west at 10 kt. The wave shows up well in GOES high density winds in the lower to mid levels of the atmosphere. No significant convection is associated with this tropical wave.

A tropical wave is in the eastern Caribbean along 65W/66W, from the U.S. Virgin Islands to central Venezuela, moving west at 10 to 15 kt. The position of the main axis of the wave was aided by 12Z sounding data. The wave is on the southwestern periphery of a 700 mb ridge and the western periphery of an upper- level trough axis to the east. No significant convection is noted at this time, but earlier convection was active through the Leeward Islands due to divergence aloft between the upper ridge and upper trough.


The monsoon trough extends from Senegal coast near 15N17W to 10N31W. The Intertropical Convergence Zone extends from 09N35W to 07N55W. Scattered moderate convection is from 11N to 19N and east of 20W.



A sharp mid to upper-level trough reaches from the Great Lakes to the western Florida Panhandle, supporting scattered showers and thunderstorms off the Panhandle coast. A broad surface trough has formed over the north Gulf related to the mid to upper level trough. Another surface trough is located over the far southwest Gulf, the remnant of the overnight troughing that forms off the western coast of the Yucatan peninsula and drifts westward overnight. A weak pressure pattern has set up overall, supporting minimal winds and seas. Little change is expected in overall conditions. By Tuesday night into Wednesday, easterly flow will increase slightly into moderate to occasional fresh conditions as ridging noses in from the lower Mississippi River valley region into the eastern Gulf waters.


Scattered showers and thunderstorms are active across much of the western Caribbean this morning. This activity is enhanced by divergence aloft on the southeastern edge of a sharp upper trough reaching into the far northwest Caribbean, and a broad mid to upper ridge extending from Nicaragua through the Windward Passage. Northerly flow aloft over the eastern Caribbean is limiting convection. Surface ridging over the central Atlantic building in the wake of the tropical wave in the eastern Caribbean will support fresh to strong trade winds, which will gradually shift from the southeast Caribbean to the south central Caribbean through mid week.


Slightly drier northerly flow aloft associated with a mid to upper level ridge across Hispaniola will limit widespread shower and thunderstorm development, although lower level moisture remains high, and some development is still possible this afternoon over higher terrain. Scattered showers and thunderstorm may form off the south coast tonight, especially ahead of tropical wave moving into the central Caribbean.


A tropical wave is moving across the basin. Refer to the section above for details. Outside the influence of Maria in the west Atlantic and Lee in the central Atlantic, surface ridging prevails across much of the remainder of the region.

For additional information please visit http://www.hurricanes.gov/marine

$$ Christensen