Tropical Weather Discussion
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421
AXNT20 KNHC 231723
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
123 PM EDT Sat Sep 23 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
1645 UTC.

...SPECIAL FEATURES...
Hurricane Maria is centered near 25.4N 72.3W at 23/1500 UTC or
about 215 nm E of Eleuthera Island and about 280 nm E of Nassau
Bahamas moving N-NW at 7 kt. Estimated minimum central pressure
is 952 mb. Maximum sustained wind speed is 100 kt with gusts to
125 kt. Scattered to numerous moderate convection is within 135 nm
of center. Scattered moderate convection is elsewhere from 22N-30N
between 69W-76W. Widely scattered moderate convection is from
20N-29N between 63W-69W...and from 27N-31N between 76W-80W. See
the latest NHC Forecast/Advisory under AWIPS/WMO headers
MIATCMAT5/WTNT25 KNHC for more details.

Tropical Storm Lee is centered near 31.9N 49.4W at 23/1500 UTC or
about 780 nm E of Bermuda and about 1155 nm WSW of the Azores
moving N at 2 kt. Estimated minimum central pressure 1007 mb.
Maximum sustained wind speed is 40 kt with gusts to 50 kt.
Widely scattered moderate convection is from 31N-33N between
49W-51W. See the latest NHC Forecast/Advisory under AWIPS/WMO
headers MIATCMAT4/WTNT24 KNHC for more details.

...TROPICAL WAVES...
Tropical wave extends from 09N22W to 22N20W moving W at 5-10 kt.
The wave coincides with a 700 mb low...the northern vortex...
centered near 21N21W and associated 700 mb troughing between
16W-28W. No significant deep convection is associated with the
wave axis at this time. Ongoing deep convection remains S of the
monsoon trough axis and will be mentioned below.

Tropical wave extends from 05N56W to 17N55W moving W at 10-15 kt.
The wave remains on the southwestern periphery of a 700 mb ridge
anchored near 22N40W and lies beneath an upper level trough axis
extending from 25N52W to a broad base deep in the tropics near
05N55W. Widely scattered moderate convection is from 05N-12N
between 49W-61W.

...ITCZ/MONSOON TROUGH...
The monsoon trough axis extends from the African coast near
14N17W to 09N23W to 06N33W. The Intertropical Convergence Zone
axis extends from 06N33W to 05N38W to 06N46W. Scattered moderate
convection is from 06N-13N between 14W-21W.

...DISCUSSION...

GULF OF MEXICO...
A middle to upper level low is noted on water vapor imagery
centered over the Florida panhandle near 31N85W with a trough axis
extending southward over the eastern Gulf to a broad base over the
Yucatan peninsula and NW Caribbean Sea. An overall weak pressure
pattern across the basin is resulting in gentle to moderate
easterly winds with areas of isolated showers and tstms generally
occurring from 23N-29N between 84W-89W under the influence of the
middle to upper level lifting dynamics in place. W of 90W...dry
and stable northerly flow aloft and generally gentle to moderate
E-SE winds are providing for fair conditions and mostly clear
skies this afternoon. Through the remainder of the weekend into
the middle of next week...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 Arklatex region into the
eastern Gulf Wednesday into Thursday.

CARIBBEAN SEA...
West-southwesterly flow aloft prevails W of 72W this afternoon as
Hurricane Maria is well north of the basin and an overall weak
pressure pattern remains in place across the central and western
Caribbean. As a result of the weaker pressure pattern...winds
remain generally light to gentle and variable at times. A couple
of weak surface troughs are analyzed...one from the coast of
eastern Cuba near 20N78W to the central coast of Honduras near 16N
86W...the other extending south of Hispaniola near 17N71W to
12N70W. Across the NW Caribbean...skies remain mostly clear with
fair conditions prevailing this afternoon. To the east...the other
surface trough is providing focus for widely scattered showers and
tstms from 13N-18N between 69W-72W. In addition...across the SW
Caribbean...the monsoon trough axis extends along 08N/09N with
scattered showers and strong tstms occurring S of 12N between
75W-83W. Finally...a tropical wave currently along 56W will
continue approaching the Lesser Antilles through Sunday and
increase the probability of isolated showers and tstms...otherwise
moderate to occasional fresh SE winds will prevail E of 70W.

...HISPANIOLA...
A surface trough currently extends from the south-central coast
near 17N71W to 12N71W across the central Caribbean Sea and
continues to provide focus for scattered showers and tstms across
the southeastern portion of the island this afternoon. The
troughing will slide westward through Sunday as weak ridging
builds in from the central Atlc from the east.

ATLANTIC OCEAN...
Outside the influence of Maria across the SW North Atlc
waters...surface ridging prevails across much of the remainder of
the central and eastern Atlc. A 1021 mb high is centered E-NE from
Bermuda near 34N56W and a 1021 mb high is centered across the
central Atlc near 31N40W. Between these two highs...Tropical Storm
Lee continues to influence the waters from 30N-35N between 45W-
53W. In addition...a middle to upper level low is centered near
27N53W generating scattered showers and tstms from 25N-32N between
39W-45W.

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

$$
HUFFMAN




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