AXNT20 KNHC 260000

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
800 PM 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 1800 UTC surface analysis and satellite imagery through 2315 UTC.


Hurricane Maria is centered near 32.0N 73.0W at 26/0000 UTC or about 230 nm south-southeast of Cape Hatteras North Carolina, moving north at 6 kt. Minimum central pressure is 965 mb. Maximum sustained winds are 70 kt with gusts to 85 kt. Maria is a very large cyclone with hurricane-force winds extending outward up to 90 nm from the center. Scattered moderate convection extends out to 240 nm from the center in the northeast semicircle. Dry air is entraining into the overall circulation with scattered moderate convection out to 150 nm in the southwest semicircle. The Morehead City, N.C. WSR-88D indicated narrow bands of scattered showers approaching the N.C. coast between Cape Lookout and Cape Hatteras with additional showers over the northern Outer Banks and the Albemarle Sound. NOAA Buoy 41025 just southeast of Cape Hatteras recently reported seas to 14 FT. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.

Hurricane Lee is centered near 30.5N 50.6W at 25/2100 UTC or about 735 nm east of Bermuda. Lee is now moving to the west- southwest at 7 kt. Estimated minimum central pressure is 983 mb. Maximum sustained winds are 75 kt with gusts to 90 kt. Lee is a small cyclone with scattered moderate isolated strong convection confined to within 60 nm of the center. Lee is forecast to remain a hurricane and turn toward the west later tonight or Tuesday, and then move toward the west-northwest by Wednesday. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.


A tropical wave extends along 34W/35W 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. Most of the wave is embedded within a fairly dry and stable environment per recent TPW imagery. As such no significant convection is associated with this tropical wave.

A tropical wave is in the eastern Caribbean along 66W/67W, from Puerto Rico to north-central Venezuela, moving west at 10 to 15 kt. The wave is situated on the eastern periphery of an upper level anticyclone over the NW Caribbean in an area dominated by mid to-upper level northerly flow. No significant convection is noted at this time.


The monsoon trough extends from Senegal coast near 15N17W to 10N33W. The Intertropical Convergence Zone extends from 09N35W to the coast of South America near 06N55W. Scattered moderate isolated strong convection is from 10N to 15N between 20W and 25W. Scattered moderate convection was noted from 06N to 09N between 32W and 41W.



A sharp mid to upper-level trough extends from the Ohio River Valley through a small cyclone near 28N86W to the Yucatan channel, supporting scattered showers and thunderstorms over the Straits of Florida and the Florida Keys. A surface reflection of the upper level trough extends from near Apalachicola, Florida to 26N87W. The surface trough located over the far southwest Gulf earlier has dissipated. Overall, a weak pressure pattern dominated the basin with light to moderate winds over the Gulf except for fresh winds along the Texas coast. 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 remain active across much of the western Caribbean this evening. 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.


Although slightly drier northerly flow aloft associated with a mid to upper level ridge prevailed over the island today, scattered strong thunderstorms developed over much of Haiti this afternoon and have continued into this evening. Low level moisture remains high with precipitable water values of 2.23" noted in the Santo Domingo rawindsonde at 1200 UTC today. Scattered showers and thunderstorms may re-form off the south coast tonight and early Tuesday, ahead of the 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 Hurricanes Maria in the western Atlantic and Lee in the central Atlantic, surface ridging prevails across much of the remainder of the west-central Atlantic, anchored by a 1022 mb high centered near 35N58W.

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

$$ Cobb