[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251811
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
211 PM EDT Fri Aug 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
1700 UTC.

...SPECIAL FEATURES...
Hurricane Harvey is centered near 27.1N 96.3W at 25/1800 UTC or
about 75 nm ESE of Corpus Christi Texas and about 80 nm S of Port
O'Connor Texas moving NW at 9 kt. Estimated minimum central
pressure is 945 mb. Maximum sustained wind speed is 95 kt with
gusts to 115 kt. Numerous moderate and scattered strong convection
is present within 90 nm of the center. Scattered moderate
convection is observed elsewhere from 25N to 31N between 90W and
98W. See latest Intermediate Public Advisory under AWIPS/WMO
headers MIATCPAT4/ WTNT34 KNHC and the full Forecast/Advisory
under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.

...TROPICAL WAVES...
A tropical wave extends from 12N27W to 22N24W moving W around 10
kt. A weak 1010 mb low is analyzed along the wave axis near
17N26W. The wave coincides with amplified 700 mb troughing.
Infrared satellite imagery shows the presence of Saharan dust
flanking the north side of the wave. Scattered moderate and
isolated strong convection is found from 11N to 14N between 28W
and 31W.

A tropical wave extends from 11N40W to 19N44W moving W around 10
kt. A weak 1010 mb low is analyzed along the wave axis near 14N43W
and is providing focus for scattered moderate and isolated strong
convection within 30 nm of the low center. The wave coincides
with amplified 700 mb troughing.

A tropical wave extends from 08N89W to 18N88W moving W at 10-15
kt. Global model guidance suggests subtle 700 mb troughing between
85W-90W moving over portions of Central America and the East
Pacific waters to the S. Scattered moderate and isolated strong
convection is present from 10N to 13N between 87W and 97W.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from 20N17W to 13N28W to 14N32W to
12N40W to 11N44W. The Intertropical Convergence Zone axis
continues from 11N44W to 11N55W then resumes from 10N58W to
10N62W. No significant deep convection is associated with the
monsoon trough or ITCZ at this time.

...DISCUSSION...

GULF OF MEXICO...
The primary weather threat for the Gulf of Mexico continues to be
Hurricane Harvey which continues to track NW toward the southern
Texas coast. Harvey continues to be steered by the western
flank of deep layer ridging extending from over the Lower
Mississippi River valley southward over the central Gulf to over
the northern Yucatan peninsula. A weak 1011 mb surface low is
centered on the Florida coast close to Sarasota near 27N82W.
Troughs extend westward from the low to 26N86W and northward from
the low to 30N84W. The low is interacting with a small upper-
level trough extending W from the Atlc over central Florida to
generate scattered moderate and isolated strong convection from
24N to 27N between 80W and 85W...including most of the southern
Florida peninsula. As Harvey slows down and impacts the NW Gulf
waters and coastal Texas through the upcoming weekend...the
troughing and weaker low pressure across the eastern Gulf waters
are expected to maintain unsettled conditions across the Florida
peninsula before the low moves NE into the SW North Atlc waters
on Sunday or Sunday night.

CARIBBEAN SEA...
Much of the NW Caribbean and portions of Central America remain
under the influence of divergent NE upper-level winds. This is
supporting scattered moderate and isolated strong convection from
20N to 23N between 81W and 85W. Otherwise...farther east...much
of the central and eastern Caribbean are beneath a subsident air
mass associated with an upper-level trough that crosses the
Caribbean from the Mona Passage to western Venezuela. Accordingly,
mostly fair conditions are currently seen at the surface.
Moderate to fresh trades prevail and this overall synoptic pattern
is expected to persist through the weekend into Monday.

...HISPANIOLA...
Mostly clear skies prevail this morning across the island with
these overall conditions expected to persist through the weekend.
Isolated afternoon showers and tstms are possible across western
Hispaniola with maximum daytime heating and instability...along
with local sea breeze effects.

ATLANTIC OCEAN...
Upper level ridging and an overall divergent upper level pattern
remains in place to the west of an upper-level trough extending
from near Bermuda to the Mona Passage. This setup is generating
scattered showers and tstms N of 27N and W of 77W and N of 26N
between 66W and 70W. A stationary front extending from SE Georgia
near 31N81W to SW Louisiana near 30N94W has little convection
associated with it. Farther east across the remainder of the
central and eastern Atlc...ridging prevails anchored by a 1027 mb
high centered W-NW of the Azores near 40N42W.

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

$$
McElroy
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