AXNT20 KNHC 250004
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Sun Sep 24 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
Hurricane Maria is centered near 29.4N 73.0W at 24/2100 UTC or
about 370 nm SSE of Cape Hatteras North Carolina moving N at 8
kt. Minimum central pressure based on aircraft data is 941 mb.
Maximum sustained winds are 90 kt with gusts to 110 kt.
Scattered to numerous moderate convection is within 135 nm of
the center. Scattered moderate convection is elsewhere from 27N-
33N between 67W-78W. See the latest NHC Forecast/Advisory under
AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.
Hurricane Lee is centered near 31.3N 49.7W at 24/2100 UTC or
about 775 nm E of Bermuda moving SE at 3 kt. Estimated minimum
central pressure is 980 mb. Maximum sustained winds are 80 kt
with gusts to 100 kt. Scattered moderate to strong convection is
within 60 nm of the center. See the latest NHC Forecast/Advisory
under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.
A tropical wave extending from 08N30W to 21N26W is moving W at
10 kt. The wave is supported by 700 mb troughing and weak 850 mb
vorticity N of 14N in the vicinity of the wave axis. Little deep
convection is associated with the wave axis at present. Ongoing
deep convection near the monsoon trough axis is mentioned below.
A tropical wave extending from 08N61W to 18N59W is moving W at
10-15 kt. The wave is on the southwestern periphery of a 700 mb
ridge and the western periphery of an upper level trough axis
extending from 22N54W deep into the tropics to near 04N56W.
Scattered moderate convection from 07N-12N between 55W-62W is
likely associated with the upper level trough already in place.
The monsoon trough axis extends from the African coast near
13N17W to 07N34W. The Intertropical Convergence Zone axis
extends from 07N34W to 08N52W. Scattered moderate isolated
strong convection is from 07N-12N between 17W-24W.
GULF OF MEXICO...
A middle to upper level low noted on water vapor imagery over
southern Alabama extends a trough axis across the central Gulf
to the northern Yucatan peninsula. A very weak pressure pattern
exists across the entire basin, resulting in gentle to moderate
easterly winds and areas of widely scattered showers under the
influence of the mid-level lifting dynamics in place. Little
change is expected in overall conditions. By Tuesday night into
Wednesday...E-SE flow will increase slightly into moderate to
occasional fresh breeze conditions as ridging noses in from the
lower Mississippi River valley region into the eastern Gulf
Wednesday into Thursday.
SW flow aloft prevails W of 75Wm, and a weak pressure pattern
remains in place across the central and western Caribbean. Winds
remain generally light to gentle. A weak surface trough analyzed
from 11N74W to 17N74W continues as a focus for scattered showers
and isolated tstms between 71W-76W. A tropical wave currently
along 60W will cross the Windward Islands overnight, increasing
chances for scattered showers and tstms N of eastern Venezuela.
Moderate to occasional fresh SE winds will prevail E of 72W.
A surface trough SW of the island enhanced showers and tstms
across southern portions of the island this afternoon. The
trough will slide further westward through Mon as weak ridging
builds in from the central Atlc.
Outside the influence of Maria in the SW North Atlc and Lee in
the central Atlc...surface ridging prevails across much of the
remainder of the region. A 1020 mb high is centered E-NE from
Bermuda near 34N58W and a 1020 mb high is centered across the
central Atlc near 28N39W. In addition...an upper level trough is
noted on water vapor imagery near 25N53W generating scattered
showers and tstms from 23N-29N between 42W-49W.
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