[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT DEC 13 2014

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.

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

THE MONSOON TROUGH CROSSES THE AFRICAN COAST NEAR 05N09W AND
CONTINUES OVER THE EASTERN ATLANTIC TO NEAR 06N20W. THE ITCZ
BEGINS AT 06N20W AND CONTINUES ALONG 7N30W TO 7N40W TO 6N48W.
SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 150 NM OF
EITHER SIDE OF THE MONSOON TROUGH AND ITCZ AXIS OVER THE
TROPICAL ATLANTIC.

...DISCUSSION...

GULF OF MEXICO...

A 1028 MB HIGH CENTERED OVER THE TENNESSEE VALLEY HAS A N-S AXIS
EXTENDING ACROSS THE CENTRAL GULF OF MEXICO. THIS IS PRODUCING
NORTH TO NORTHEASTERLY FLOW OF 10 TO 15 KT ACROSS THE EASTERN
GULF AND EAST TO SOUTHEAST FLOW OF 10 TO 15 KT ACROSS THE
WESTERN GULF. ISENTROPIC LIFT OCCURRING IN THE RETURN FLOW
ACROSS THE TX/LA COAST AND OFFSHORE WATERS IS PRODUCING
SCATTERED SHOWERS FROM 27N TO 30N BETWEEN 92W AND 96W. OTHER
PATCHES OF SHOWERS ARE OCCURRING IN THE MOIST LOW LEVELS IN THE
SW GULF. SUBSIDENCE AND DRY AIR SUPPORT FAIR WEATHER ACROSS THE
REMAINDER OF THE BASIN. OVER THE NEXT 24 HOURS A DISTURBANCE
MOVING ACROSS THE PLAINS WILL COMBINE WITH RETURN FLOW IN THE NW
GULF TO SUPPORT SHOWERS OVER THAT PORTION OF THE BASIN.

CARIBBEAN SEA...

UPPER LEVEL DIFFLUENCE ACROSS MUCH OF THE SW CARIBBEAN IS
INTERACTING WITH A VERY MOIST AIRMASS TO PRODUCE SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 9N TO 17N BETWEEN 75W
AND 84W. ELSEWHERE...SCATTERED SHOWERS ARE OCCURRING WITHIN 100
NM OF A LINE FROM THE NICARAGUA/HONDURAS BORDER NEAR 15N83W NE
TO THE EASTERN TIP OF CUBA NEAR 20N75W. THESE ARE ASSOCIATED
WITH REMNANT MOISTURE CONVERGENCE ALONG A FORMER FRONTAL ZONE.
DRY AIR AND SUBSIDENCE SUPPORTS FAIR WEATHER ACROSS THE EXTREME
NW CARIBBEAN AND MUCH OF THE CENTRAL AND EASTERN PORTIONS OF THE
BASIN. 15 TO 20 KT TRADE WINDS DOMINATE MUCH OF THE BASIN WITH A
FEW PATCHES OF 25 KT OBSERVED OVER THE SW BASIN. OVER THE NEXT
24 HOURS CONVECTION WILL CONTINUE OVER THE SW CARIBBEAN. A COLD
FRONT MOVING S TOWARD E CUBA WILL BECOME STATIONARY OVER E CUBA
ON SUNDAY. SHOWERS WILL BE POSSIBLE OVER CUBA AND THE OFFSHORE
CARIBBEAN WATERS N OF JAMAICA SUNDAY AND SUNDAY NIGHT.

HISPANIOLA...

A NEARLY STATIONARY SURFACE TROUGH EXTENDS OVER THE W ATLANTIC
INCLUDING THE TURKS AND CAICOS. SHOWERS ASSOCIATED WITH THIS
TROUGH ARE JUST NW OF HAITI TODAY. A COLD FRONT MOVING S ACROSS
THE BAHAMAS WILL FORCE THE TROUGH SE OVER THE NEXT TWO DAYS.
SHOWER AND THUNDERSTORM ACTIVITY WILL INCREASE OVER THE ISLAND
SUNDAY AND SUNDAY NIGHT AS THE TROUGH MOVES NEAR THE ISLAND AND
THE COLD FRONT STALLS OUT OVER E CUBA.

ATLANTIC OCEAN...

AN UPPER TROUGH WITH AXIS ALONG 65W SUPPORTS A COLD FRONT OVER
THE WESTERN ATLANTIC FROM 31N64W TO 27N70W TO NEAR 26N80W
INCLUDING THE N BAHAMAS. ISOLATED SHOWERS ARE WITHIN 50 NM OF
THE COLD FRONT. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM OF
A LINE FROM 26N62W TO 31N55W ASSOCIATED WITH LIFT FROM THE UPPER
TROUGH. A NEARLY STATIONARY SURFACE TROUGH EXTENDS FROM 25N66W
TO 21N73W...INCLUDING THE TURKS AND CAICOS. SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ARE WITHIN 70 NM OF THE TROUGH AXIS.
FARTHER EAST...A PAIR OF SURFACE TROUGHS ARE OVER THE CENTRAL
ATLANTIC. THE FIRST TROUGH EXTENDS FROM 23N50W TO 21N46W WITH
ISOLATED SHOWERS AND THUNDERSTORMS WITHIN 70 NM NE OF THE TROUGH
AXIS. THE SECOND SURFACE TROUGH EXTENDS FROM 17N38W TO 21N36W
AND IS INTERACTING WITH AN UPPER LOW CENTERED NEAR 26N39W.
ISOLATED MODERATE CONVECTION IS WITHIN 80 NM OF THE SURFACE
TROUGH AXIS. WIDELY SCATTERED MODERATE CONVECTION IS FROM 21N TO
29W BETWEEN 29W AND 39W. OVER THE EASTERN ATLANTIC...A COLD
FRONT EXTENDS FROM 31N29W TO 31N15W. SHOWERS ARE OCCURRING
WITHIN 75 NM S OF THE FRONT. N TO NE WINDS UP TO 30 KT ARE N OF
THE FRONT. OVER THE NEXT 24 HOURS THE COLD FRONT OVER THE W
ATLANTIC WILL MOVE E TO NEAR 31N60W TO 24N70W. THE PORTION OF
THE FRONT OVER THE BAHAMAS WILL BECOME STATIONARY. CONVECTION
WILL CONTINUE TO THE E OF THE UPPER TROUGH AS IT MOVES FROM 65W
TO NEAR 60W. STRONG WINDS WILL CONTINUE TO BE POSSIBLE N OF THE
FRONT IN THE FAR EASTERN ATLANTIC THROUGH SUNDAY NIGHT.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
LATTO


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