[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 310608
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
208 AM EDT Thu Aug 31 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 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURES...

Tropical Depression Harvey is centered over NW Louisianan near
31.2N 92.6W at 31/0300 UTC , moving NNE at 8 kt. Estimated
minimum central pressure is 998 mb. Maximum sustained wind speed
is 30 kt with gusts to 40 kt. Rain is noted on radar over SE Texas
and W Louisiana. Isolated showers and thunderstorms are occurring
along the northern Gulf coast from Mobile to the western Florida
panhandle. Catastrophic flooding is still expected over southeast
Texas and southwest Louisiana. See the 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.

T.S. Irma is centered near 16.4N 32.2W at 31/0300 UTC or about
450 nm W of the Cabo Verde Islands, moving W at 10 kt. Estimated
minimum central pressure is 999 mb. Maximum sustained wind speed
is 55 kt with gusts to 65 kt. Numerous moderate and scattered
strong convection is found within 60 nm of the center. Scattered
moderate convection is observed elsewhere from 12N to 20N between
29W and 37W. See the latest Intermediate Public Advisory under
AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the full
Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC
for more details.

...TROPICAL WAVES...

A tropical wave over the central Atlantic extends from 24N48W to
10N50W, moving west at 15 kt. The wave coincides with an
amplified 700 mb trough in initial model wind fields. TPW
satellite imagery shows an area of modest deep layer moisture.
Satellite imagery also shows an area of Saharan dust to the west
of the wave. Scattered moderate convection is seen from 09N to 11N
between 47W and 52W.

A tropical wave over the central Caribbean extends from 22N75W to
08N77W, moving west at 10 kt. The wave coincides with modest 700
mb troughing in initial model wind fields and curvature of low-
level winds in scatterometer data. SSMI TPW imagery shows this
wave is embedded in an area of modest deep layer moisture.
Scattered moderate convection is over E Cuba and Haiti. Isolated
thunderstorms are occurring over the Windward Passage, eastern
Cuba and SW of Jamaica.

A tropical wave over central America extends from 22N88W to
10N88W, moving west at 10 to 15 kt. The wave coincides with subtle
700 mb troughing in initial model wind fields. TPW satellite
imagery shows this wave is embedded in an area of modest deep
layer moisture. Scattered moderate and isolated strong convection
is found mostly inland from the Yucatan Peninsula to S Nicaragua
from 08N to 18N between 83W and 90W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from Senegal on the African coast near
14N17W to the Cabo Verde Islands near 16N24W. The monsoon trough
resumes W of Irma from 14N34W to 10N40W to 10N48W. The ITCZ
continues from 10N53W to 10N61W. Besides the convection associated
with Irma, scattered moderate and isolated strong convection is
present from 05N to 10N between 32W and 44W.

...DISCUSSION...

GULF OF MEXICO...

Tropical Depression Harvey is centered over Louisiana near 32N92W.
Convection associated with Harvey has all but departed the Gulf.
Only some residual showers and thunderstorms linger over the
western Florida Panhandle and near Mobile Alabama. Please see the
special features section above for additional details. The tail
end of a stationary front is over N Florida from 29N80W to 31N86W.
Scattered moderate convection is N of the front over S Georgia.
Further S, scattered moderate convection is over W Cuba. An area
of scattered showers has developed over the Bay of Campeche south
of 23N and west of 93W. Harvey is expected to slowly weaken and
reach NW Mississippi by Thursday evening. Little change is
expected across the remainder of the basin.

CARIBBEAN SEA...

Two tropical waves are moving across the Caribbean waters. See
the Tropical Waves section above for additional details. The
eastern portion of the E Pacific monsoon trough passes over the
southwest Caribbean along 10N. Low-level convergence near the
trough is producing scattered moderate convection over northern
Colombia and eastern Nicaragua. Satellite-derived wind data
depicts moderate to fresh trades covering the basin.

...HISPANIOLA...

The showers and thunderstorms that were associated with a tropical
wave have shifted westward over the Windward Passage and eastern
Cuba as a tropical wave moves away over Cuba and the western
Caribbean. Expect a drier weather pattern during the next couple
of days as the tropical wave moves farther W of the island.

ATLANTIC OCEAN...

T.S. Irma is over the eastern Atlantic, while a tropical wave is
moving over the central Atlantic. Refer to the appropriate
sections above for details about these features. A surface trough
extends from 30N45W to 26N46W. Scattered moderate convection is
present from 24N to 29N between 44W and 47W. The remainder of the
basin is dominated by a 1028 mb high centered over the Azores near
39N26W which ridges west-southwestward through a 1019 mb high
centered SE of Bermuda near 26N59W to the eastern Gulf of Mexico.

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

$$
McElroy
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