[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011717
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
117 PM EDT Fri Sep 1 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
1715 UTC.

...SPECIAL FEATURES...

Hurricane Irma is centered near 18.5N 37.8W at 01/1500 UTC or
about 750 nm west-northwest of the Cabo Verde Islands, moving
west-northwest at 11 kt. Estimated minimum central pressure is
972 mb. Maximum sustained wind speed remains at 95 kt with gusts
to 115 kt. Numerous moderate and scattered strong convection is
observed from 16N-21N between 36W-41W. See the latest Public
Advisory issued under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and
Marine Forecast/Advisories issued under AWIPS/WMO headers
MIATCMAT1/WTNT21 KNHC for more details.

...TROPICAL WAVES...

A tropical wave has emerged from the west coast of Africa over
the eastern Atlantic. The wave extends its axis from 16N24W to
05N23W, moving west around 15 kt. The wave coincides with an
amplified 700 mb trough in initial model wind fields. The SSMI TPW
satellite imagery shows the wave embedded in an area of deep
layer moisture. Satellite imagery also shows an area of Saharan
dust to the northeast of the wave. Scattered moderate convection
is found from 09N-14N between 23W-27W.

A tropical wave over the central Atlantic with axis extending
from 22N54W to 08N55W, moving west around 10 kt. The wave coincides
with an amplified 700 mb trough in initial model wind fields. The
SSMI TPW satellite imagery shows the wave is embedded in an area
of modest deep layer moisture. Satellite imagery also shows an
area of Saharan dust to the west of the wave. At this time, no
convection is related to this wave.

A tropical wave over the western Caribbean with axis extending
from 22N84W to 05N84W, moving west at 10 to 15 kt. The wave
coincides with modest 700 mb troughing in initial model wind
fields. SSMI TPW imagery shows this wave is embedded in an area of
modest deep layer moisture. Isolated showers and thunderstorms
are observed over Nicaragua and Honduras and adjacent waters south
of 20N and west of 80W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast at 11N15W to
14N29W then resumes from 14N41W to 10N53W. Aside from the
convection related to the tropical wave along 24W, isolated
moderate convection is observed within 100 nm south of the monsoon
trough between 14W-30W.

...DISCUSSION...

GULF OF MEXICO...

A surface trough extends over the Bay of Campeche from 23N97W to
19N95W. Scattered moderate convection prevails south of 25N and west
of 92W. Another surface trough is over the northeast Gulf
extending from 30N87W to 27N90W with scattered moderate convection
along and south of it affecting the waters between 24N-27W and
east of 90W. In the upper levels, an upper-level trough extends SW
over the NW Gulf from Louisiana is producing strong subsidence
over the NW Gulf. Convergent upper-level winds are generally
inhibiting convection over that area. The remainder of the Gulf
has a large amount of upper level moisture. Expect the upper-level
trough to move E and maintain generally dry conditions over the
northern Gulf over the next 24 hours.

CARIBBEAN SEA...

A tropical wave is over the western Caribbean. Refer to the
section above for details. Farther south, the eastern portion of
the E Pacific monsoon trough passes over Costa Rica and Panama
into northern Colombia enhancing isolated showers. An upper-
level trough heading southwest from the Atlantic into the
northeast Caribbean is producing upper-level convergence and
inhibiting convection over the northeast Caribbean. Satellite
derived wind data depicts moderate to fresh trades covering the
basin. A similar weather pattern will prevail through the next 24
hours.

...HISPANIOLA...

Presently there is no significant convection over the island.
Expect the dry weather pattern to prevail during the next couple
of days as a weak upper-level trough passes overhead and inhibits
convection.

ATLANTIC OCEAN...

Hurricane Irma is over the eastern Atlantic, while two tropical
waves are over the eastern and central Atlantic. Please see the
sections above for details. A surface ridge prevails over the west
Atlantic anchored by a 1019 mb high centered near 25N70W. To the
east, a cold front extends from 32N52W to 26N65W with scattered
showers and thunderstorms. The remainder of the basin is
dominated by a 1029 mb high centered south of the Azores near
37N27W. Moderate trades generally prevail south of the ridge and
north of the monsoon trough to the west of 40W.

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

$$

ERA
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