[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011705
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
105 PM EDT Sun Oct 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
1700 UTC.

...SPECIAL FEATURES...
A frontal boundary curves westward from 1011 mb low pres centered
near 30N72W to 27.5N76W to the vicinity of Vero Beach Florida
near 29N81W. A strong pressure gradient N of the boundary and to
the NW of the low is generating near gale to gale force NE to E
winds W of 73W and N of 29N. The gradient is forecast to gradually
relax during the next 24 hours as the boundary weakens and slowly
sinks southward. This will allow the gale force winds in this
area to subside. See the latest NWS High Seas Forecast under
AWIPS/WMO headers MIAHSFAT2/ FZNT02 KNHC for more details.

...TROPICAL WAVES...
A tropical wave that has just emerged from the African coast
extends from 03N18W to 12N16W moving W around 20 kt. The wave is
embedded in an area of deep-layer moisture and coincides with
modest troughing at 700 mb. Scattered moderate and isolated strong
convection is seen from 04N to 10N between 14W and 21W.

A tropical wave over the Central Atlantic extends from 07N41W to
21N48W moving W at 10-15 kt. The wave coincides with 700 mb
troughing and continues to interact with an upper-level low
centered near 16N47W. Divergent upper-level winds on the east side
of the low are supporting a large area of scattered moderate and
isolated strong convection from 05N to 18N between 33W and 43W and
from 16N to 19N between 43W and 48W.

A tropical wave over the Central Caribbean extends from 09N74W to
18N71W moving W around 10 kt. An upper-level low centered over
Haiti continues to interact with the wave and produce numerous
moderate and scattered strong convection from 12N to 16N between
69W and 72W. Scattered moderate and isolated strong convection is
found elsewhere from 11N to 17N between 68W and 75W. A surface
trough...fractured energy from the tropical wave...extends from
19N71W to 23N69W. The trough is also being induced by the upper
level low. Divergent upper-level winds east of the low are
triggering scattered moderate and isolated strong convection from
19N to 22N between 68W and 71W. The upper level low will weaken
slowly and retrograde SW but remain close enough to produce active
convection across Puerto Rico and Hispaniola through Monday.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from Sierra Leone on the African coast
near 08N13W to 07N25W. The Intertropical Convergence Zone
continues from 07N25W to 07N33W to 08N38W. Other than convection
associated with tropical waves, there is no significant convection
associated with the monsoon trough and ITCZ.

...DISCUSSION...

GULF OF MEXICO...
Broad surface troughing covers the Gulf, with more pronounced
troughing observed over the NE Gulf from 24N87W to 29N83W and
along the coast of Mexico from 19N94W to 22N97W to 24N97W. The
surface trough along the Mexican coast is supporting scattered
moderate and isolated strong convection within 90 nm of the Gulf
coast of Mexico from 18N to 25N. A frontal boundary passes just
south of the northern Gulf coast from near Corpus Christi Texas to
the Mississippi Delta to the Florida Big Bend. A tight pressure
gradient N of the front is supporting near gale-force winds
between the front and the Northern Gulf Coast east of Louisiana.
This area of winds will spread southward over the NE Gulf during
the next couple of days as the front sags southward and weakens.
Near gale force winds will subside to strong as the pressure
gradient north of the boundary slowly relaxes.

CARIBBEAN SEA...
Active convection will continue in conjunction with the tropical
wave crossing the central Caribbean as a weakening upper-level low
noted on water vapor imagery over Haiti moves SW generally in
tandem with the wave during the next 24 hours. Scattered showers
and tstms are occurring generally over the Dominican Republic with
these features. Elsewhere...an upper-level low centered over the
NE Yucatan is generating scattered moderate and isolated strong
convection west of a line from 15N79W to 22N83W. This activity
includes western Cuba and the Straits of Yucatan.
Otherwise...moderate to fresh E-SE trades will persist through
Monday, except for light to moderate winds over the SW Caribbean
south of 12N.

...HISPANIOLA...
Currently the island remains under the influence of an upper
level low centered over Haiti and a tropical wave moving W in
tandem with the upper level feature. The upper level low will
move SW ahead of the tropical wave and continue generating
scattered showers and tstms across the region through tonight.

ATLANTIC OCEAN...
Outside of the influence of the strengthened pressure gradient
across the far NW portion of the SW North Atlc and far NE Gulf of
Mexico generating near gale to gale force winds...broad surface
ridging extends SW from a 1028 mb surface high centered E of the
Azores near 39N18W. The ridging dominates the Atlantic to the east
of 70W.

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

$$
McElroy
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