[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030605
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 AM EDT Sun Sep 3 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
0545 UTC.

...SPECIAL FEATURES...

Hurricane Irma is centered near 18.3N 46.2W at 03/0300 UTC or
about 890 nm E of the Leeward Islands moving W at 12 kt.
Estimated minimum central pressure is 973 mb. Maximum sustained
wind speed is 95 kt with gusts to 115 kt. Numerous strong convection
is from 17N to 20N between 44W and 48W. Scattered moderate
convection is elsewhere from 15N to 21N between 42W and 52W. Some
strengthening is forecast during the next 48 hours. See the
latest NHC Forecast/Advisory under AWIPS/WMO headers
MIATCMAT1/WTNT21 KNHC for more details.

...TROPICAL WAVES...

A tropical wave is in the E Atlc just W of a 1014 mb low located
near 09N27W. The wave axis extends from 15N33W to 09N30W, moving
W at 10 kt. The wave is in a region of low vertical wind shear,
however enhanced IR imagery show some Saharan dry air and dust in
the wave environment. CIRA LPW imagery at the lower levels confirm
the presence of dry air in the vicinity of the wave. Shallow
moisture and upper level diffluence support scattered showers and
tstms from 02N to 13N between 23W and 37W.

A tropical wave is in the E Caribbean with axis extending from
21N63W to 12N67W, moving W at 15-20 kt. The wave is in a region
of low vertical wind shear, however it continues being affected by
dry air subsidence from aloft. Shallow moisture support scattered
to isolated showers over the NE Caribbean, Puerto Rico, the Mona
Passage and Hispaniola.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 13N16W to
09N27W to 10N36W. Aside from the convection associated with the
tropical wave in the E Atlc, scattered moderate convection is from
05N to 09N E of 22W.

...DISCUSSION...

GULF OF MEXICO...

Water vapor imagery indicates a middle to upper level trough
extending over the E CONUS S to a base just N of the Bay of
Campeche. The trough supports a dissipating stationary front
extending across the Florida panhandle to near 29N91W. A pre-
frontal surface trough extends from 28N83W to 21N87W. Another
surface trough is in the central Bay of Campeche extending from
25N90W to 18N94W. Upper level diffluent flow just to the E of the
trough base along with abundant low level moisture across the
southern basin continue to support scattered showers and tstms
generally S of 26N E of 93W and S of 22N W of 93W. Otherwise, mostly
light to gentle variable wind is noted across the Gulf with
locally moderate flow mainly in the far SW basin. Generally
surface lower pressure will persist in the SW Gulf in the form of
a trough the next two days while a weak ridge will build over the
eastern half of the basin.

CARIBBEAN SEA...

Upper level diffluent flow to the ESE of a trough base located N
of the Bay of Campeche in the Gulf of Mexico continue to support
scattered to isolated showers over NW Caribbean waters W of 80W.
Middle level diffluent flow, however, is supporting numerous heavy
showers and scattered tstms over Guatemala, San Salvador and the
western half of Honduras. In the SW basin, the E extension of the
EPAC monsoon trough support scattered showers and tstms S of 13N W
of 80W. A tropical wave is moving across E Caribbean waters, thus
supporting scattered to isolated showers in the NE basin as well
as Puerto Rico and Hispaniola. See the tropical waves section
above for further details. Water vapor imagery show dry air aloft
in the remainder basin, which is supporting fair weather
conditions. Otherwise, moderate to fresh trades are basin-wide.
Looking beyond this weekend, Hurricane Irma is forecast to
approach 60W Tuesday night into Wednesday.

...HISPANIOLA...

Isolated showers and tstms are expected to continue through the
overnight hours into Sunday as a tropical wave approaches from the
east. The wave is expected to pass west of the island by late
Monday with conditions gradually improving into Tuesday.

ATLANTIC OCEAN...

Hurricane Irma remains on the southwestern periphery of a ridge
anchored by a 1027 mb high centered SW of the Azores near 34N33W.
See special features section for details. A middle to upper level
trough progressing over the E CONUS supports isolated showers
over the far western SW North Atlc waters, including interior
portions of Florida. Farther east, an upper level low continue to
support a stationary front extending from 30N58W SW to 26N64W with
isolated showers occurring within 75 nm either side of the
boundary. The stationary front is forecast to weaken a dissipate
by late Sunday.

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

$$
Ramos
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