[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271800
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 AM EST Fri Jan 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.

...SPECIAL FEATURES...

A cold front extends from SW Florida to near 23N90W where it
becomes stationary along 21.5N94W to 20N95W to 18N94W. Then, the
front continues, as a stationary front, across the eastern
slopes of the Sierra Madre mountain in Mexico. The cold front
will continue to move slowly SE, reaching the Straits of Florida
by Saturday morning while the stationary front will lift N as a
warm front across the western Gulf. Computer model suggests that
a low will form along the frontal boundary over the western Gulf
early on Saturday, with a new cold front moving across the Gulf
region Saturday afternoon through Sunday. NW to N gale force
winds and building seas are forecast S of 25N west of the front
Saturday afternoon into Sunday morning. See latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more
details.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough enters the Atlantic Ocean through Sierra Leone
at 07N12W and continues to 06N15W. The Intertropical Convergence
Zone axis extends from 06N15W to 03N30W to 01N40W to the South
American coast and near the Equator at 51W. Scattered moderate
convection is from 00N-05N between 20W-30W, within about 120 nm
north of the ITCZ axis between 30N-38N, and from 00N-06N W of
45W.


...DISCUSSION...

GULF OF MEXICO...

A frontal boundary extends across the Gulf region. Please, see
Special Features section for details. Doppler radar indicates a
few showers in association with the front across south Florida
and regional waters, including the Florida keys. A band of
multilayered clouds is related to the front, and visible
satellite imagery hints that a weak low is developing across the
SW Gulf. Low clouds are aslo noted baking up along the eastern
slopes of the Sierra Madre mountain. Currently, N-NE winds in
the 15-20 kt range are noted north of the front. In the upper
levels, zonal flow and abundant mid-upper level moisture
dominate the northern Gulf while a ridge with moderate to strong
upper level subsidence and implied dry air mass is noted over
the southern Gulf, including SE Mexico and the Yucatan
Peninsula.

CARIBBEAN SEA...

The southern tip of a stationary front is over the NE Caribbean
and extends from the northern Leeward Islands to near 16N65W.
Moderate to locally fresh NE winds are N of the front. Patches
of low level clouds with embedded light showers are noted in
association with the frontal boundary affecting the northern
Leeward Islands. Part of this activity is also reaching the
US/UK Virging Islands. Similar cloudiness is aslo noted across
the remainder of the basin, more concentrated south of Cuba and
over the Cayman Islands. Moisture associated with the front will
continue to affect the NE Caribbean today and tonight while the
front is forecast to gradually dissipated across this area
through Saturday. Scatterometer data provide observations of
near gale force winds near the coast of Colombia ,with fresh to
strong winds across the remainder of the south- central
Caribbean. These winds are forecast to persist over the next
several days, with pulsing winds no near gale force at night
near the coast of Colombia. A cold front is expected to reach
the Yucatan Channel by Sunday morning. Aloft, a ridge/trough
/ridge pattern dominates the basin producing moderate to strong
upper level subsidence across the entire region. The upper-level
trough extends from the northern Leeward Islands to the Guajira
Peninsula and supports the aforementioned stationary front.

...HISPANIOLA...

Mostly fair conditions and clear skies prevail over Hispaniola
as strong subsidence continues to provide an overall stable
environment over the region. On Saturday,  expect some increase
in moisture, under a SE flow, with the risk of light showers.

ATLANTIC OCEAN...

A cold front enters the forecast area naer 31N73W and continues
SW to south-central Florida into the Gulf of Mexico. A recent
ASCAT pass shows very well the wind shift associated with the
front as well as moderate to fresh winds on either side of the
front, forecast to reach the Straits of Florida by Saturday
morning, then stall and weaken.  A second cold front stretches
from 31N36W to 21N47W, then continues as a stationary front from
this point to the northern Leeward Islands. A surge of moisture
with embedded light showers is associated with the front over
the NE Caribbean. This activity is forecast to drift NW across
the NE Caribbean the rest of today and tonight. Between fronts,
a 1022 mb high pressure is centered near 27N55W. This system is
forecast to move eastward to a position near 28N40W by Saturday
morning. The remainder of the area is under the influence of
another high pressure of 1025 mb located just NW of the Canary
Islands near 30N19W. The high will move NE and away from the
forecast region in about 12-24 hours. The next cold front is
expected to move off NE Florida on Sunday, reaching a position
from 31N73W to the NW Bahamas and western Cuba Saturday
afternoon.

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

$$
GR
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