[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211746
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1246 PM EST WED DEC 21 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
1700 UTC.

...SPECIAL FEATURES...

.None.

...THE ITCZ/THE MONSOON TROUGH...

The ITCZ emerges from Liberia on the western coast of Africa at
06N10W to 02N22W to 03N39W to the Brazilian coast of South
America at 01N49W. Scattered moderate and isolated strong
convection is noted from 01N to 04N between 16W and 23W and from
03S to 02N between 23W and 35W.

...DISCUSSION...

...THE GULF OF MEXICO...

As of 1200 UTC, a quasi-stationary front extends from near Ft
Myers Florida at 27N82W to 24N93W to 22N95W to the Bay of Campeche
at 18N93W. The front is beginning to weaken and has no associated
deep convection. Over the SW Gulf of Mexico S of 22N and W of
front, winds are NW to N 20-25 kt, with seas to 10 ft. The
remainder of the Gulf has 10-20 kt NE to E winds. An upper-level
high is centered over central Mexico near 21N101W. An upper-level
ridge extends eastward from central Mexico over the Gulf of
Mexico. Upper-level convergence on the east side of the ridge is
creating strong subsidence. The upper-level high over Mexico will
gradually shift eastward during the next couple of days, keeping
the ridge over the Gulf of Mexico. The front is expected to
dissipate during the next 24 hours. Another frontal boundary will
sink southward toward the northern Gulf coast on Friday, then
stall. Moderate to fresh E to SE winds will generally prevail over
the Gulf on Saturday and Sunday.

...THE CARIBBEAN SEA...

15-25 kt NE surface winds predominate over the Caribbean. Lighter
winds and some showers are found in the vicinity of the monsoon
trough over the extreme SW Caribbean just north of Panama and
Costa Rica. In the upper levels, convergent upper-level flow from
the NW is producing strong subsidence over the central and western
Caribbean. An upper-level low is centered over the central
Caribbean south of Hispaniola near 17N69W. Divergent upper-level
winds on the east side of the low are triggering scattered
moderate convection mainly south of Puerto Rico from 14N to 18N
between 64W and 68W. The convection is expected to slowly spread W
to the central Caribbean during the next day or so. The upper-
level low will weaken toward the end of the week, which will cause
the associated convection to diminish as it shifts westward in
tandem with the low.

...HISPANIOLA...

A sharp transition line between deep moisture and pronounced
drying and subsidence is currently oriented southwestward from
the Mona Passage to between Colombia and Haiti near 14N73W. The
line will shift W during the next day or so and allow showers over
Puerto Rico to spread slowly west across the Dominican Republic
tonight and Thursday, then possibly Haiti on Friday before the
upper-level low weakens.

...THE ATLANTIC OCEAN...

A quasi-stationary front extends over the western Atlantic from
31N71W to Stuart Florida at 27N80W. Scattered showers are present
along and up to 120 nm N of the front to the east of the Florida
peninsula. A weak surface trough is producing scattered showers
between Florida and the Bahamas between 25N and 28N. This trough
is expected to quickly weaken and dissipate. Another weak surface
trough is over the central Atlantic from 22N56W to 26N54W.
Scattered showers are within 120 nm of the trough. This trough has
little in the way of associated convection. Another surface trough
is over the eastern Atlantic from 22N25W to 27N28W. The troughs
over the central Atlantic and eastern Atlantic are associated with
mid to upper-level lows. The system over the central Atlantic is
weaker and should dissipate during the next couple of days.
Scattered showers are observed on the east side of this trough
from 22N to 27N between 21W and 26W. A 1036 mb high is centered
over the eastern Atlantic near the Azores at 38N27W. A ridge axis
extends WSW from the high to 32N60W. Expect the front to dissipate
over the next 24 hours before a new cold front moves eastward from
the southeastern United States on Friday.

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

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