[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201745
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1245 PM EST SUN NOV 20 2016

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...

An area of low pressure of 1006 mb continues to meander over the
SW Caribbean located near 11N80W. Although the system's circulation
appears to have become a little better defined, the associated
thunderstorm activity is rather limited at this time. Environmental
conditions are marginally conducive for development, and a
tropical depression could form during the next couple of days
while the low moves slowly and erratically. An Air Force
reconnaissance aircraft is scheduled to investigate the area later
this afternoon. The latest Tropical Weather Outlook gives this
system a medium change of tropical cyclone formation during the
next 48 hours.

Gulf of Mexico Gale Warning: A strong cold front is moving across
the Gulf waters. At 1200 UTC, the front extends from south Florida
to 23N87W to the central Bay of Campeche near 18N94W. Strong high
pressure behind the front extends a ridge across eastern Mexico
and the western Gulf and is producing gale force winds along the
coast of Veracruz, Mexico mainly S of 23N and W of the front.
Fresh to strong northerly winds are blowing elsewhere in the wake
of the front. Scatterometer data confirmed the presence of these
winds. The front will exit the Gulf tonight and winds are forecast
to diminish below gale force at 1800 UTC. High pressure behind
the front will dominate the Gulf waters over the next several days
while shifting eastward.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends across Africa into the east Tropical
Atlantic near 12N16W to 11N20W where it transitions to the ITCZ
and continues along 8N30W to 10N41W to 9N60W. Scattered moderate
convection is noted from 5N to 10N between 24W and 28W. No
significant convection elsewhere.

...DISCUSSION...

...GULF OF MEXICO...

A gale warning remains in effect for the SW Gulf in association
with a strong cold front currently moving across the area. Please,
see Special Features section for details. High pressure is
bridging the cold front and dominates the entire area. Visible
satellite imagery shows cold air stratocumulus clouds, associated
with the advection of cold air over relatively warm waters,
covering the Gulf waters N of the front and W of 87W. Clear skies
dominates the NE Gulf under the influence of a fresh to locally
strong northerly wind flow. Aloft, strong upper-level subsidence
and implied dry air mass is noted across the Gulf N of 24N while
SW-W flow is S of 24N, with these winds advecting some mid-upper
level moisture from the EPAC across central Mexico into the Gulf
region. Moderate to fresh southerly return flow will set up over
the NW Gulf late on Monday and persist through Tuesday night ahead
of the next cold front forecast to enter the region on Wednesday.

...CARIBBEAN SEA...

An area of low pressure continues to meander over the SW Caribbean.
Please, see Special Features section for details. A stationary
front extends from the eastern tip of Dominican Republic to near
16N73W. A recent Ascat pass indicates fresh NE winds within about
60 nm W of the frontal boundary. A cluster of moderate to isolated
strong convection is near the southern end of the front and covers
the area from 14N-17N between 71W-75W. Scattered showers and
thunderstorms are affecting the ABC Islands and regional waters.
A diffluent pattern aloft is helping to induce this convective
activity. A moist and unstable atmosphere is forecast to persist
across the basin roughly SE of a line from Dominican Republic to
the coast of Nicaragua near Puerto Cabezas through Monday. A band
of showers with embedded thunderstorms, related to the low pressure
area in the SW Caribbean, is affecting the Caribbean coast of
Costa Rica. This pattern is forecast to persist over the next 2 or
3 days, depending on the movement of the low pressure. A ridge
from the Atlantic and low-topped trade wind showers will continue
to dominate the Lesser Antilles. A cold front, currently extending
across the Gulf of Mexico, will move into the NW Caribbean tonight.
This will bring fresh to strong winds over a large area of the
basin, particularly from the Windward Passage to Costa Rica
through Tuesday. A tight pressure gradient is forecast to persist
across parts of the central and western Caribbean between the
above mentioned low pressure and the high pressure behind of the
front. In fact, the most recent scatterometer pass revealed the
presence of fresh to strong N-NE winds in the lee of Cuba to NE
Honduras and W of the low pressure to the coast of Nicaragua.

...HISPANIOLA...

Moisture will diminish across Haiti on Monday, but atmospheric
conditions are expected to remain moist and unstable over
Dominican Republic, mainly across the eastern part of the island,
due to the proximity of the nearly stationary frontal boundary.

...ATLANTIC OCEAN...

A cold front enters the forecast region near 31N53W, then continues
SW to near 23N60W where it becomes stationary, extending over
Hispaniola and the central Caribbean. A recent Ascat pass indicates
fresh to strong southerly winds just ahead of the front N of 28N.
Isolated showers are along the frontal boundary. A second cold
front extends from 31N71W to SE Florida followed by fresh to
strong winds. This front is forecast to reach from 28N65W to
central Cuba early on Monday, and from 26N65W to eastern Cuba on
Tuesday. The first front will remain nearly stationary over the
next 24-48 hours while gradually weakening. A surface trough is
analyzed from 21N33W to 16N35W to 12N38W and is generating
isolated showers and thunderstorms. Multilayered clouds, with
possible embedded showers, are between the trough and the west
coast of Africa. Fresh to strong winds are seen on the east side
of the trough to about 27W due to the pressure gradient between
the trough and a ridge across the eastern Atlantic. A surface
trough, reflection of an upper-level low, persists across the
Atlantic and stretches from 25N40W to 20N41W. Some shower activity
persists in association with this trough. Moderate to fresh easterly
winds are between the northern end of trough and a 1027 mb high
pressure located W of the Azores near 38N38W.

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

$$
GR
This weather bulletin was brought to you by:
www.nashvilleweather.net