[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271748
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1248 PM EST Wed Dec 27 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
1715 UTC.

...ITCZ/MONSOON TROUGH...
The monsoon trough enters the Atlantic Ocean through Liberia,
Africa and continues to near 05N10W. The Intertropical Convergence
Zone axis extends from 05N10W to 03N20W to 05N35W to the Equator
near 52W. Scattered moderate convection is from 01N-06N between
27W-41W.

...DISCUSSION...

GULF OF MEXICO...
A weak low pressure persits across the north-central Gulf and now
is located near 29N90W. A cold front extends from the low center
to just S of Brownsville, Texas into NE Mexico and along the Rio
Grande River valley. A stationary front will also extends eastward
from the low center to across northern Florida, with a warm front
sector between the low and 86W. Mainly low-level clouds with
embedded showers, and patches of fog are noted in the vicinity of
the low/front. The pressure gradient between the low/front and
strong high pressure N of area is resulting in fresh to strong
NE-E winds behind the frontal boundary. The remainder of the basin
is under the influence of a surface ridge extending from the SE
CONUS. The ridge is providing gentle to moderate E-SE winds S of
the frontal boundary, with the exception of moderate to locally
fresh NE-E winds near the Yucatan Peninsula likely associated with
the thermal trough. The low will shift E to near 27N88W this
evening, then weaken to a trough tonight that will meander along
86W through early Fri before losing identity. The cold front will
move southward across the Gulf waters through Thursday night while
gradually dissipate. High pressure will build in in the wake of
the front. Looking ahead, the next strong cold front is expected
to emerge off the Texas and Louisiana coasts Sunday evening
followed by strong to gale-force winds and building seas of up to
14-15 ft.

CARIBBEAN SEA...
The most recent scatterometer data show fresh to strong winds
across the south-central Caribbean near the coast of Colombia,
moderate to fresh winds over the remainder of the central
Caribbean and eastern Caribbean, and gentle to moderate winds
over the western Caribbean. Patches of low-level moisture
embedded in the trade wind flow are producing isolated to
scattered passing showers across the Greater and Lesser Antilles
from time to time. Little change in this weather pattern is
expected during the next couple of days. Expect strong to near
gale force nocturnal winds near the coast of Colombia tonight.
Strong NE winds are then expected along the NW coast of Colombia
during the overnight and early morning hours through the upcoming
weekend. E swell currently across the tropical Atlantic waters,
including the E Atlantic passages, will begin to subside from the
NE on Thu.

...HISPANIOLA...
Isolated to scattered showers carried by the trade winds will
continue to affect the island from time to time. Mostly dry and
stable conditions are expected to persist during the next couple
of days under the influence of a mid to upper-level ridge and
associated strong subsidence. A larger patch of moisture may
cross the island Thursday night into Fri, slightly increasing the
likelihood of showers.

ATLANTIC OCEAN...
A cold front enters the discussion area near 31N59W extending SW
to 30N62W, and becoming stationary to near the NW Bahamas. Mainly
low clouds with embedded isolated showers are occurring along the
frontal boundary. The stationary front will lift N as a weak warm
front today with a surface low developing near 31N79W by early
Thu. The low will move NE dragging a new cold front SE through the
Central Bahamas by Fri. Another surface low will develop near
29N78W on Thu night, and race E-NE passing N of Bermuda on Fri
night. In fact, a recent scatterometer pass hints the formation
of a low across the front near 29N74W. The remainder of central
and eastern Atlantic is under the influence of a surface ridge
anchored by a 1033 mb high centered S of the Azores near 34N28W.
The pressure gradient between this high and lower pressure in the
vicinity of the ITCZ/monsoon trough is resulting in a large area
of fresh to strong winds between the coast of Africa and the
Lesser Antilles, with seas of up to 11-12 ft. The high pressure
will move E and weaken some over the next 24 hours.

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

$$
GR
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