[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211038
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
638 AM EDT FRI OCT 21 2016

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
1030 UTC.

...SPECIAL FEATURES...

A broad area of low pressure is centered east of the northern
Bahamas. The central pressure of the low is 1001 mb and is
located near 28N73W. Scattered moderate convection and isolated
tstms are within 150 nm from the low center. To the east of the
low center, a rainband supported by a diffluent environment aloft
generates scattered showers and tstms from 20N to 36N between 60W
and 70W. Showers also continue across Hispaniola, mainly across
Dominican Republic, with GOES QPE imagery showing there
accumulations of up to 2 inches over the last 6 hours. There is
still a medium chance for this system to become a subtropical or
tropical cyclone before it merges with an approaching cold front
well offshore of the United States east coast tonight.

A tight pressure gradient between a cold front and high pressure
building in its wake will generate gale force winds in the Gulf of
Mexico tonight. The front is expected to be along 29N82W to
26N90W to 19N95W and the gale winds from 21N to 24N west of 96W with
seas to 8 ft. These conditions are forecast through Saturday. Please
see the High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC for more details.

...TROPICAL WAVES...

Tropical wave is in the central Atlantic extending from 06N to
16N with axis near 44W, moving W at 15 kt over the past 24 hours.
The wave is in a region of unfavorable to neutral deep layer wind
shear. Furthermore, CIRA LPW imagery from surface to 850 mb show
pockets of dry air in the wave environment while water vapor
imagery show dry air in the middle to upper levels. These factors
are limiting the convection to scattered showers from 06N to 14N
between 37W and 53W.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through the coast of Africa reaching the
eastern Atlantic near 09N13W to 04N20W to 03N29W. The ITCZ begins
near 03N30W and extends to 04N40W. For convection information see
the tropical waves section.

...DISCUSSION...

GULF OF MEXICO...

A middle to upper level trough extending from Wisconsin south to
a base over Louisiana and Texas coastal waters support a cold
front that extends from 31N87W SW to NE Mexico near 25N97W. Both
the front and the remnants of a surface trough in the Bay of
Campeche support scattered to isolated showers west of 92W. Gentle
to moderate NE wind is ahead of the cold front where strong dry
air subsidence from aloft support fair weather. The front is
forecast to extend along 29N82W to 26N90W to 19N95W tonight with
gale force winds developing in the basin from 21N to 24N west of
96W. See special features section for further details. The front
is expected to reach S Florida Saturday near sunrise.

CARIBBEAN SEA...

Southeasterly flow across the eastern Caribbean continues to
advect moisture to the north-central basin where upper level
divergence support scattered showers N of 16N between 66W and
75W, including Hispaniola. The GOES QPE imagery show rain
accumulations of up to 2 inches over the last 6 hours in the
Dominican Republic. This may result in life-threatening flash
floods and mud slides over portions of Hispaniola. A surface
trough extends from eastern Jamaica near 17N76W to a 1007 mb low
NE of Nicaragua near 15N82W and support isolated showers within
90 nm either side of its axis. A cold front will reach the NW
basin Saturday night. This will allow the continuation of showers
across Hispaniola over the weekend.

...HISPANIOLA...

Southeasterly flow across the eastern Caribbean advects moisture
to the north-central basin where upper level divergence support
scattered heavy showers over southern Hispaniola adjacent waters
to 16N. Over Hispaniola, the GOES QPE imagery show rain
accumulations of up to 2 inches in the Dominican Republic over the
last 6 hours. This may result in life-threatening flash floods and
mud slides over portions of Hispaniola. A cold front will reach
the NW Caribbean Saturday night. This will allow the continuation
of showers across Hispaniola over the weekend.

ATLANTIC OCEAN...

The main feature of interest in the basin is an area of low
pressure centered east of the northern Bahamas, which associated
rainband generates scattered showers and tstms from 20N to 36N between 60W
and 70W. Scattered moderate convection and isolated tstms are
within 150 nm from the low center. There is a medium chance for
this system to become a subtropical or tropical cyclone before it
merges with an approaching cold front well offshore of the United
States east coast tonight. See special features for further
details. Fresh to near gale force winds are in the SW N Atlantic
waters associated with this area of low pressure. Please see the
High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC
for more details. The other feature of interest is a tropical wave
in the central Atlantic. See the tropical waves section for
further details. Over the central Atlantic, a middle to upper
level trough support a cold front that extends from 30N28W to
28N42W with isolated showers within 60 nm either side of the
boundary. The remainder basin is under the influence of a surface
ridge and fair weather. A cold front will move over SW N Atlantic
waters tonight through the weekend.

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

$$
RAMOS
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