[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 270602 CCA
TWDAT

Tropical Weather Discussion...CORRECTED
NWS National Hurricane Center Miami FL
202 AM EDT Sun Aug 27 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.

Corrected for designation of Harvey

Based on 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...SPECIAL FEATURES...
Tropical Storm Harvey is centered near 29.3N 97.4W at 27/0600 UTC
or about 40 nm NW of Victoria Texas and about 60 nm ESE of San
Antonio Texas remaining stationary. Estimated minimum central
pressure is 998 mb. Maximum sustained wind speed is 40 kt with
gusts to 50 kt. Scattered moderate and isolated strong convection
is from 29N-32N between 94W-96W. Scattered moderate convection is
elsewhere from 28N-33N between 90W-99W. 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.

A 1011 mb low is centered across the northern Florida peninsula
near 29N82W. Surface troughing extends N-NE to the offshore waters
of Jacksonville and SW across Tampa Bay to 26N84W in the eastern
Gulf of Mexico. Scattered to numerous moderate and isolated strong
convection is from 25N-28N between 81W-84W with scattered moderate
convection elsewhere from 24N-29N between 80W-87W. The surface
low remains under the influence of a relative divergent flow aloft
on the eastern periphery of an upper level ridge anchored over the
central Gulf of Mexico near 26N90W. The low is forecast to track
NE through Sunday into the SW North Atlc waters and move along the
coast to the Mid-Atlc region by Tuesday night.

...TROPICAL WAVES...
A tropical wave extends from 15N28W to 25N25W moving W at 5-10
kt. The wave coincides with amplified 700 mb troughing between
23W-33W. Infrared satellite imagery shows the presence of Saharan
dust surrounding the wave environment N of the monsoon trough
axis. No significant deep convection is associated with the wave
at this time.

A tropical wave extends from 11N51W to 22N52W moving W at 15-20
kt. The wave coincides with broad troughing at 700 mb between 48W-
56W and continues to generate scattered moderate convection from
16N- 21N between 51W-58W.

A tropical wave extends from 10N66W to 20N65W moving W at 15-20
kt. This wave has moved across the central Atlc waters and Lesser
Antilles the past few days as a surface trough and continues to
provide scattered showers across the eastern Caribbean Sea and
adjacent Atlc coastal waters N of Puerto Rico and the US/UK Virgin
Islands this evening.

A tropical wave extends from 13N97W to 20N96W moving W at 15 kt.
Global model guidance suggests subtle 700 mb troughing and a
maximum in 850 mb relative vorticity S of 19N between 93W-100W
moving over portions of southern Mexico and the adjacent East
Pacific waters. Scattered moderate and isolated strong convection
is from 15N-19N between 91W-100W.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from the African coast near 17N16W to
12N40W to 12N48W. Scattered moderate convection is from 03N-15N
between 10W-22W. Isolated moderate convection is from 08N-14N
between 39W-48W.

...DISCUSSION...

GULF OF MEXICO...
With the surface circulation of Harvey inland across southern
Texas...scattered showers and tstms continue across the NW Gulf
waters generally N of 27N W of 91W. Harvey remains on the
northwestern periphery of an upper level ridge anchored over the
central Gulf near 26N90W that extends influence over the Lower
Mississippi River valley...the entire Gulf basin...and the
Florida peninsula. To the east of Harvey...upper level divergence
associated with the ridging supports the Special Features low
centered across the Florida peninsula near 29N82W. The remainder
of the Gulf is under mostly moderate southerly winds with the
exception of gentle to moderate cyclonic winds across the eastern
Gulf in closer proximity to the low across Florida. Harvey is
expected to remain in the vicinity of the Texas coast through mid-
week with a ridge axis extending from the Florida peninsula to
the SW Gulf as the Florida low moves NE into the SW North Atlc
waters.

CARIBBEAN SEA...
Much of the NW Caribbean and portions of Central America are under
the influence of NE flow aloft with convective debris upper level
cloudiness moving over the NW Caribbean. To the east...an upper
level low is centered over the Windward Passage region generating
widely scattered showers and tstms from 17N-20N between 72W-
79W...including portions of western Hispaniola and Jamaica. As
the upper level low continues to retrograde...upper level ridging
will build in over the eastern portion of the basin through
Monday. A tropical wave currently across the eastern Caribbean
along 66W will likely benefit with a favorable divergent
environment aloft supporting scattered showers and isolated tstms
occurring within 210 nm either side of the wave axis. Lastly...
moderate to fresh trades prevail and this overall synoptic pattern
is expected to persist through Tuesday.

...HISPANIOLA...
An upper level low is centered over the Windward Passage region
this evening supporting widely scattered showers and tstms across
western portions of the island. As the low moves westward through
Sunday night...a tropical wave is expected to move across the
island and adjacent coastal waters bringing scattered showers and
isolated tstms through early Monday.

ATLANTIC OCEAN...
Upper level ridging and an overall divergent upper level pattern
prevails over the SW North Atlc this evening generating scattered
showers and tstms remaining W of a line from 32N65W near Bermuda
to 29N76W to the coast of western Cuba near 23N79W. Water vapor
imagery also indicates long wave upper level troughing offshore of
the eastern CONUS with the base of this trough remaining
generally N of 33N. The trough supports a stationary front
extending from 34N64W to coastal Georgia near 32N81W to the
Florida panhandle. An upper level low is centered near 30N48W and
supports a surface trough analyzed from 26N57W to 31N53W.
Isolated showers and tstms are occurring from 28N-33N between
46W-53W. The remainder of the central and eastern Atlc is under
the influence of a surface ridge anchored by a 1029 mb high
centered W-NW of the Azores near 40N35W.

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

$$
HUFFMAN
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