AXNT20 KNHC 261758

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
158 PM EDT Tue Sep 26 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 1630 UTC.


Hurricane Maria is centered near 33.8N 73.1W at 26/1800 UTC or about 143 nm southeast of Cape Hatteras North Carolina, moving north at 6 kt. Minimum central pressure is 974 mb. Maximum sustained winds are 65 kt with gusts to 80 kt. Maria is a very large cyclone with hurricane-force winds extending outward up to 90 nm from the center. Scattered moderate convection is within 360 nm of this system in the eastern semicircle. Stable air on the western semicircle is resulting in mainly showers within 300 nm west of the center. Buoy data indicates seas of 15 ft extending over 150 nm south of the center, with 8 ft seas about 300 nm south of the center. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.

Hurricane Lee is centered near 29.9N 53.7W at 26/1500 UTC or about 585 nm east of Bermuda. Lee is moving to the west at 9 kt. Estimated minimum central pressure is 975 mb. Maximum sustained winds are 90 kt with gusts to 110 kt. Lee is a small cyclone with numerous moderate and isolated strong convection confined to within 75 nm of the center. Lee is forecast to remain a hurricane the next couple of days as it continues west today, then moving 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 is exiting the coast of Africa with an axis extending from around 13N16W to 04N13W, moving westward at around 15 to 20 kt. Scattered moderate convection is associated with a squall line within about 150 nm west of the wave axis, south of 10N.

A tropical wave extends along 40W from 20N to 06N, moving west at 10 to 15 kt. This wave is well defined in 700 mb wind fields. However, aside from the southern portion of the wave, most of this wave is embedded within a fairly dry and stable environment per recent SSMI TPW imagery. Scattered moderate convection is south of 11N between 37W and 44W.

A tropical wave is in the eastern Caribbean along 70W/72W, from 20N to 08N, moving west at 10 to 15 kt. The wave is embedded within a weak 700 mb trough. Isolated moderate convection is within 90 nm of the wave axis north of 15N, and is partially due to upper level diffluence over the region.


The monsoon trough extends from the coast of Africa near 15N17W to 10N23W to 08N38W. The Intertropical Convergence Zone extends from 08N43W to 09N60W. Aside from convection associated with the tropical waves, scattered moderate to strong convection is from 08N to 14N between 50W and 56W. Widely scattered moderate convection is within 90 nm of the monsoon trough between 22W and 38W, and the ITCZ axis west of 56W.



A surface trough extends over the southwest Gulf from 23N95W to 18N93W, and is void of deep convection. An upper low over the eastern Gulf supports scattered thunderstorms south of 28N, east of 89W. Weak ridging extends from Ohio Valley high pressure, southwestward over the northern Gulf, supporting gentle to moderate winds over the basin outside of thunderstorm activity. Over the next 24 hours thunderstorms will continue over the southeast Gulf.


A tropical wave is over the E Caribbean. Please refer to the tropical waves section for details. A surface trough extends from 21N82W to 13N83W and is located under a broad upper level anticyclone that is supportive of scattered moderate convection from 14N to 20N between 79W and 83W. Widely scattered thunderstorms are elsewhere north of 12N between 75W and 86W. A ridge of high pressure over the SW N Atlantic supports moderate to locally fresh trades over the Caribbean, except gentle winds over the southwest Caribbean near the E Pacific monsoon trough. Little change is expected over the next 24 hours.


A tropical wave is crossing the island today. However, dry air is limiting shower and thunderstorm activity to mainly isolated in coverage. Little change is expected through Wednesday.


Two tropical waves are moving across the basin. Please refer to the tropical waves section above for details. Hurricanes Maria in the western Atlantic and Lee in the central Atlantic are discussed in the special features section above. A plume of moisture is being pulled northeast across the bahamas and surrounding waters by an upper low over the eastern Gulf of Mexico. This plume combined with upper level diffluence from the upper low supports numerous showers and scattered thunderstorms from 22N to 28N, west of 74W. Low level convergence well to the southeast of Maria, combined with upper level diffluence from an upper low to the east is supporting scattered showers and thunderstorms N of 22N between 63W and 70W. Elsewhere, surface ridging prevails across much of the remainder of the central and the eastern Atlantic, anchored by a 1021 mb high centered near 37N45W.

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

$$ Latto