[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080003
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
702 PM EST SAT JAN 7 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

A cold front is currently analyzed across NW portions of the SW
North Atlc, the Florida Keys, and Gulf of Mexico from 25N80W to
western Cuba near 22N84W to the NE Yucatan Peninsula near 20N87W.
The front continues moving eastward and will clear the Gulf of
Mexico tonight and remain impacting the SW North Atlc waters
through the remainder of the weekend into Monday. Gale force winds
are in the Gulf of Mexico S of 22N W of 93W with seas from 15 to 23
ft. In the Atlantic, fresh to near gale force winds with frequent
gusts to gale force are W of the front. Near gale to gale force
SW winds are N of 30N within 60 nm E of the front with seas
building to 11 ft. Both gale events are forecast to end by Sunday
afternoon. See 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 07N13W to
07N16W where the Intertropical Convergence Zone axis begins and
continues along 02N22W to 0N32W to the NE coast of Brazil near
01S44W. Scattered to isolated showers are from 01S to 07N between
17W-35W.

...DISCUSSION...

GULF OF MEXICO...

The main impact across the basin tonight continue to be the
Special Features cold front that extends from 25N80W to western
Cuba near 22N84W to the NE Yucatan Peninsula near 20N87W. The
front continues to be supported aloft by a middle to upper level
trough noted on water vapor imagery with axis extending over the
Great Lakes SW to a base over the Bay of Campeche. Shallow
moisture along with upper level diffluence support scattered
showers across the Florida Straits and the Yucatan Channel. A
strong pressure gradient between the front and strong high
pressure building behind it support gale force winds S of 22N W
of 93W with seas from 15 to 23 ft. Also, frequent gusts to gale
force winds are possible in the north-central basin. Otherwise,
the strong ridge anchored by a 1044 mb high centered over Texas will
continue to slide eastward to the mid-Atlc coast by Monday
morning. As this occurs, the current wind field will gradually
diminish from west to east Sunday night into Monday as SE return
flow establishes across the NW Gulf.

CARIBBEAN SEA...

Water vapor imagery continues to indicate strong subsidence over
most regions of the basin with the exception of the SE and SW
Caribbean where abundant low to middle level moisture support
widespread scattered to isolated showers. Scattered showers are
also in the Yucatan Channel associated with a cold front moving
across the Florida Straits, the Yucatan Channel and the Yucatan
Peninsula. This front will move over NW Caribbean waters later
tonight with fresh to strong winds behind it that will increase to
near gale force by Sunday afternoon as the front continue to move
E-SE across the NW basin waters. A fairly weak pressure gradient across
the basin maintain moderate trades across the E basin. Fresh to
strong trades are over the south-central basin with the strongest
winds along the coast of Colombia. This area of winds will
expand to the remainder SW basin Sunday where it will merge with
the area of strong to near gale force winds associated with the
cold front.

...HISPANIOLA...

Dry air and strong subsidence aloft are providing an overall
stable environment that is expected to persist through Sunday
evening. However, a cold front entering the NW Caribbean later
tonight will slide E-SE to the eastern tip of Cuba by late Sunday
where it will stall through Monday night. The front will then move
across Hispaniola and Puerto Rico Tuesday through Wednesday
morning. This will support showers across the Island from Sunday
evening through Wednesday evening.

ATLANTIC OCEAN...

Southwesterly flow aloft prevails over the SW North Atlc region as
a middle to upper level trough approaches from the west. This
upper trough with axis extending from the Great Lakes to a base
over the Bay of Campeche supports a 1006 mb low centered off the
mid-Atlantic coastal waters. A cold front extends from this low SW
to 30N75W to the northern Bahamas to the Straits of Florida. Fresh
to near gale force winds with frequent gusts to gale force are W
of the front. Near gale to gale force SW winds are N of 30N within
60 nm E of the front with seas building to 11 ft. Enhanced satellite
imagery and GOES lighting density data show scattered showers and
tstms within 210 nm SE-E of the front and isolated showers W of
the boundary. As the front passes...winds will shift northerly
ranging from strong to near gale strength. This N-NE wind field
will quickly move southeastward across the region through Monday
as strong high pressure anchors to the north across the mid-Atlc
coast. Otherwise, surface high pressure anchored N of the area
extends a ridge axis S-SW across the remainder SW N Atlc and the
central Atlc, thus providing fair weather conditions. Across the
eastern Atlc, a 1006 mb low is centered near 29N26W with a surface
trough axis extending S-SW to 26N25W. This low is supported aloft
by a broad cut-off middle to upper level low centered near 29N26W.
Widely scattered showers and isolated tstms are occurring
generally east of the surface low N of 25N between 17W-25W.

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

$$
Ramos
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