[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071703
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1203 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 1200 UTC surface analysis and satellite imagery through
1630 UTC.

...SPECIAL FEATURES...
A cold front is currently analyzed across NW portions of the SW
North Atlc...the northern Florida peninsula...and Gulf of Mexico
from 32N79W to near Tampa Bay to 22N90W to 18N94W. The front
continues moving eastward and will clear the Gulf of Mexico by
Saturday night late and remain impacting the SW North Atlc waters
through the remainder of the weekend into Monday. Near gale to
gale force northerly winds are occurring generally S of 26N W of
94W with strong to near gale force winds occurring elsewhere W of
the front. Near gale to gale force W-SW winds are forecast to
materialize by this afternoon N of 30N within 150 nm E of the
front in the SW North Atlc. 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 05N09W to
05N14W to 02N24W. The Intertropical Convergence Zone axis extends
from 02N24W to the Equator near 27W. Scattered moderate
convection is S of 05N between 16W-35W.

...DISCUSSION...

GULF OF MEXICO...
The main impact across the basin this afternoon is the Special
Features cold front that extends from near Tampa Bay into the SW
Gulf to 20N94W to 18N94W. A pre-frontal surface trough axis is
analyzed from the front near 23N88W SW to the coast of southern
Mexico near 18N93W. The front continues to be supported aloft by
a middle to upper level trough noted on water vapor imagery with
axis extending over the Ohio River valley SW to over the lower
Mississippi River valley. Scattered showers and tstms are
occurring in association with the front generally within 120 nm
either side of the boundary E of 87W. Scattered showers and
isolated tstms are elsewhere within 120 nm E of the front. Aside
from the near gale to gale force northerly winds occurring across
western portions of the basin...strong high pressure anchored by a
1041 mb high centered in the Rio Grande river valley near 28N100W
will continue to slide eastward to the mid-Atlc coast by Sunday
night. As this occurs...the current wind field of strong to near
gale winds will gradually diminish from west to east Sunday night
into Monday as SE return flow re-establishes itself across the NW
Gulf.

CARIBBEAN SEA...
Water vapor imagery continues to indicate strong subsidence over
the entire basin with the exception of scattered high level
cloudiness mainly over SW portions. In addition...a fairly weak
pressure gradient is noted across the basin with moderate to fresh
trades expected to persist through the evening and overnight
hours. Slightly stronger trades...fresh to occasional strong...are
expected within close proximity to the coast of Colombia and NW
Venezuela. By Saturday night late...a cold front is forecast to
move into the NW Caribbean resulting in strong to near gale N-NE
winds that will spread southeastward to 73W by Monday morning.

...HISPANIOLA...
Conditions remain fair with mostly sunny skies this afternoon. Dry
air and strong subsidence aloft are providing an overall stable
environment that is expected to persist the next several days
keeping overall conditions tranquil across the island.

ATLANTIC OCEAN...
Southwesterly flow aloft prevails over the SW North Atlc region as
a middle to upper level trough approaches from the west...
currently with axis extending from over the Ohio River valley
southwestward to over the lower Mississippi River valley. The
troughing supports a 1006 mb low centered off the coast of South
Carolina near 32N78W and the associated cold front analyzed SW to
near Jacksonville Florida then into the SE Gulf of Mexico.
Scattered showers and tstms are occurring N of 28N between 69W-
79W...and from 25N-31N between 79W-83W...including a large portion
of the Florida peninsula. Strong to gale force SW winds are
expected through the evening and overnight hours E of frontal
passage. 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...for the remainder of the afternoon and
evening...a ridge axis extends from the central Atlc near 30N53W
W-SW to central Cuba near 22N79W. Farther east...the same ridge
continues to influence much of the central Atlc anchored by a 1029
mb high centered near 33N45W. Finally...across the eastern
Atlc...a 1006 mb low is centered near 30N26W with a surface
trough axis extending S-SW to 27N26W to 24N29W. 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 from 25N-38N
between 16W-26W.

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

$$
HUFFMAN
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