[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011037
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
637 AM 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 0600 UTC surface analysis and satellite imagery through
1100 UTC.

...SPECIAL FEATURES...

Hurricane Irma is centered near 18.2N 36.5W at 01/0900 UTC or
about 730 nm west-northwest of the Cabo Verde Islands, moving
west-northwest at 10 kt. Estimated minimum central pressure is 967
mb. Maximum sustained wind speed remains at 100 kt with gusts to
120 kt. Numerous moderate and scattered strong convection is seen
within 60 nm of the center. Scattered moderate and isolated strong
convection is found elsewhere from 15N to 21N between 34W and
39W. Irma remains a category 3 hurricane on the Saffir- Simpson
Hurricane Wind Scale. See the latest Public Advisories 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 just emerged from the west coast of Africa
over the eastern Atlantic. The wave extends from 17N20W to 04N20W,
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 is embedded in an area of deep layer
moisture. Satellite imagery also shows an area of Saharan dust to
the northeast of the wave. Numerous moderate and isolated strong
convection is found within 60 nm of 11.5N24W. Scattered moderate
and isolated strong convection is found elsewhere from 04N to 13N
between 24W and 30W.

A tropical wave over the central Atlantic extends from 21N53W to
14N55W to 08N54W, 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. Scattered moderate
convection is seen from 17N to 19N between 48W and 50W.

A tropical wave over the western Caribbean extends from 21N83W to
09N82W, 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 thunderstorms are observed over eastern
Nicaragua and Honduras from 11N to 18N between 83W and 85W and
over western Cuba from 21N to 24N between 78W and 84W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from Senegal on the African coast at
14N17W to 13N20W to 15N30W then resumes from 15N38W to 11N52W.
The ITCZ reaches from 10N56W to 10N61W. Scattered moderate and
isolated strong convection is observed from 05N to 12N between
35W and 41W. Numerous moderate and scattered strong convection is
taking place within 60 nm of 12.5N41.5W. Scattered moderate and
isolated strong convection is observed elsewhere from 11N to 14N
between 39W and 44W.

...DISCUSSION...

GULF OF MEXICO...

A tropical wave moving from southern Mexico into the eastern
Pacific Ocean is producing scattered moderate and isolated strong
convection over the Bay of Campeche south of 23N and west of 91W.
A weak surface trough over the north central Gulf is producing
scattered showers and isolated thunderstorms within 30 nm either
side of a line from 27.5N87W to 23N91W. In the upper levels, an
upper level trough extending SW over the NW Gulf from Louisiana is
producing strong subsidence over the NW Gulf. Convergent upper-
level winds are generally inhibiting convection over the Gulf
except near western Cuba and over the Bay of Campeche. 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. See above. Farther
S, the eastern portion of the E Pacific monsoon trough passes
over Costa Rica and Panama into northern Colombia. Convection
associated with the trough is limited to isolated thunderstorms
south of 11N. A weak upper-level trough heading SW from the Atlc
into the NE Caribbean is producing upper-level convergence and
inhibiting convection over the NE Caribbean while another upper-
level trough from western Cuba to Panama is producing weak upper-
level convergence over the western Caribbean. A tropical wave over
the western Caribbean is generating convection over western Cuba.
See the tropical waves section for more details. Satellite
derived wind data depicts moderate to fresh trades covering the
basin.

...HISPANIOLA...

Presently there is no significant convection over the island.
Expect the dry weather pattern to prevail across the island 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, and tropical waves
are over the eastern and central Atlantic. Please see above. A
frontal boundary extends across the W Atlantic, analyzed as a cold
front from 32N53W to 27N64W, then continues as a weakening
stationary front to 27N71W, then as a weakening warm front to
31N81W. Scattered showers and isolated thunderstorms are observed
along and up to 60 nm ahead of the cold front to the east of 62W.
A 1019 mb surface high is centered N of the front near 31N69W. The
remainder of the basin is dominated by a 1029 mb high centered NE
of the Azores near 41N20W that ridges SW to near 26N54W. Moderate
trades generally prevail south of the ridge and north of the
monsoon trough and ITCZ to the west of 40W.

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

$$
McElroy
This weather bulletin was brought to you by:
www.nashvilleweather.net