[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271636
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1136 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 while gradually
dissipated 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. Little change is expected through
Saturday.

ATLANTIC OCEAN...

A cold front is over the W Atlantic from 32N72W to central
Florida near 27.5N80W. Scattered showers are within 90 nm of the
front. A 1022 mb high is centered E of the Bahamas near 26N58W
producing fair weather. A cold front is over the central
Atlantic from 32N36W and continues S-SW to 26N40W to 20N53W. A
stationary front continues to the NE Caribbean Sea near 17N60W.
Scattered showers are within 120 nm E of front. A 1024 mb high
is centered over the E Atlantic near 31N24W. A cold front is
over the E Atlantic from 32N09W to 29N12W to 25N23W. Scattered
showers are within 90 nm of the front. Of note in the upper
levels, an upper level trough is N of 20N between 35W-55W
supporting the central Atlantic frontal system. Expect both
fronts to move E over the next 24 hours with showers.

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

$$
GR
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