[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210603
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
203 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

A broad area of low pressure is centered east of the northern
Bahamas. The central pressure of the low is 1002 mb and is located
near 27N73W. Scattered moderate convection and isolated tstms are
within 150 nm from the low center. However, 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 Friday night. To the east
of the low center, a rainband supported by a diffluent
environment aloft generates numerous heavy showers and tstms from
22N to 30N between 64W and 68W. 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. Life-threatening flash floods and mud slides are
possible over portions of Hispaniola.

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 Friday night. The front is expected to be along 29N82W to 25N96W
to 19N95W and the gale winds S of 24N west of the frontal
boundary with seas to 9 ft. 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 45W, moving W at 15-20 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 07N to 14N between 38W and 53W.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through the coast of Africa reaching the
eastern Atlantic near 15N17W to 08N22W to 04N28W. Aside of the
convection related to the tropical wave, isolated showers are from
01N to 10N east of 30W.

...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 29N91W SW to southern Texas near 26N97W.
Ahead of the front, a surface trough extends from 26N92W to
18N94W. Both the front and the surface trough support scattered to
isolated showers west of 91W. 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 25N96W to 19N95W by Friday night with gale force winds
developing in the basin S of 24N west of the front. 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 heavy showers N of 15N between 66W
and 76W, 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 18N76W to NE Nicaragua near 14N83W andsupport 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 15N. 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 numerous heavy showers and tstms from 22N to
30N between 64W and 68W. 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 Friday night. See
special features for further details. Fresh to near gale force
winds are in the SW N Atlantic waters associated with this low.
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. The remainder basin
is under the influence of a surface ridge.

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

$$
RAMOS
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