[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221752
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1252 PM EST Wed Nov 22 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
1630 UTC.

...SPECIAL FEATURES...
A 1012 mb low is centered near 25N89W with a cold front surging
southward to the west of the low. As of 1500 UTC, a pre-frontal
trough extends from the low to near Vera Cruz, Mexico. The low
and cold front will merge later today as the low moves NE.
Frequent gusts to gale force have been occurring this morning over
the NW Gulf to the NW of the cold front. Sustained gale force
winds will occur over the SW Gulf with the passage of the pre-
front trough, and re- enforced by the cold front. The gusts over
the NW Gulf will diminish below gale force late this evening. The
sustained gale over the SW Gulf will end Friday morning. See the
latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/
FZNT02 KNHC for more details.

A new area of low pressure of 1013 has developed near 28N71W.
gale force winds are forecast to develop this evening over the SE
semicircle of the low. This gale will persist over this portion
of the low through tonight as the low moves NE and north of 31N.
See the latest NWS High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/ FZNT02 KNHC for more details.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from the African coast near 09N13W to
06N20W. The Intertropical Convergence Zone extends from 06N20W to
06N35W to 08N48W. A surface trough is just east of where the ITCZ
terminates and extends from 11N50W to 06N52W. Scattered moderate
convection is from 06N to 11N between 40W and 60W, and from 03N
to 11N between 11W and 35W.

...DISCUSSION...

GULF OF MEXICO...
A complex system is dominating the Gulf basin today. A stationary
front extends across central Florida to a weakening 1013 mb low
near 28N85W. The stationary front continues to another low of 1012
mb near 25N89W. As of the 1500 UTC analysis, a pre-frontal trough
extended from the low to the SW Gulf near Vera Cruz, while a cold
front lagged just behind the lows over the north central Gulf
from 31N85W to 26N94W, then surges southward over the western Gulf
to near Tampico, Mexico. This location of the front was confirmed
by both surface observation dewpoints and scatterometer wind data.
Scattered moderate convection with numerous embedded
thunderstorms is occurring within 300 nm SE of the cold front.
Frequent gusts to gale force are occurring over the NW gulf NW of
the front, and sustained gale force winds are developing behind
the pre-frontal trough over the SW Gulf. Please refer to the
special features section for more details. Fresh to strong NE
winds are elsewhere NW of the cold front. Mainly gentle to
moderate winds are SE of the pre-frontal trough and lows. Over the
next 24 hours the cold front will merge with the central Gulf
low. The central Gulf low will move NE and absorb the NE gulf low.
Thunderstorms will continue SE of the cold front.

CARIBBEAN SEA...
A surface trough extends from 21N80W to 11N80W. This trough is
interacting with moist SW flow in the mid to upper levels to
support a cluster of moderate convection from 16N to 22N between
77W and 80W, and a broad area of shower activity S of 16N W of the
trough axis. Mainly gentle to moderate winds are over the western
Caribbean W of 78W. Moderate to locally fresh E to SE winds are
over the Caribbean E of 78W. Over the next 24 hours showers and
thunderstorms will continue near the surface trough.

...HISPANIOLA...
Clear skies and relatively tranquil conditions are noted across
the island today. Scattered thunderstorms may begin to affect the
south portion of the island later today as an upper trough to the
west digs SE toward the region.

ATLANTIC OCEAN...
A weakening cold front extends from 31N75W to 28N79W, where it
transitions to a dissipating stationary front over central
Florida. No convection is noted with this front. A new area of low
pressure of 1013 mb as of 1500 UTC was centered near 27N71W. A
developing warm front extends from 25N66W to the low. A developing
cold front extends from the low to near 24N76W. A pre-frontal
trough extends from the low to near 22N75W. A cluster of moderate
convection is within 210 nm E of the low. Widely scattered
thunderstorms are within 210 NM SE of the developing cold front.
Strong southerly winds are between the pre- frontal trough and
warm front N of 25N. Fresh to strong SE winds extend from the warm
front NE to beyond the 31N border of our area of discussion, W of
60W. The winds over the SE semicircle of the low are expected
increase to near gale or gale force later this evening as the low
moves NE and deepens. Please refer to the special features
section for more details on this gale. Farther east, a cold front
enters the area of discussion near 31N43W and extends to 28N55W
where it transitions to a stationary front to 39N62W, then
transitions to a warm front to beyond 31N67W. No deep convection
is noted with this front at this time. A weakening frontal system
covers the E Atlantic waters. A cold front enters the area of
discussion near 31N17W to 23N26W where it transitions to a
stationary front to a 1012 mb low near 21N42W. A surface trough
extends from this low to near 17N53W. No deep convection is
associated with this system. Over the next 24 hours the new low
over the western Atlantic will exit the area of discussion with a
trailing front over the SW N Atlantic waters. The cold front over
the central Atlantic will continue eastward. The frontal system
over the E Atlantic will dissipate, while the associated low
drifts SW.

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

$$
Latto
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