[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI DEC 07 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE FAR E
TROPICAL ATLC NEAR 6N11W TO 6N14W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 4N30W 7N44W TO SOUTH AMERICA NEAR 5N53W. SMALL
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM THE EQUATOR
TO 4N FROM 4W ACROSS THE PRIME MERIDIAN...FROM 6N-8N BETWEEN
18W-25W...AND FROM 10N-13N BETWEEN 38W-46W. CLUSTERS OF ISOLATED
MODERATE CONVECTION DOT THE AREA WITHIN 120 NM EITHER SIDE OF
THE ITCZ BETWEEN 20W-46W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE EXTENDS FROM ACROSS MEXICO TO OVER THE
MISSISSIPPI VALLEY AND COUPLED WITH THE UPPER TROUGH THAT
EXTENDS OVER THE FLORIDA PENINSULA IS GIVING THE GULF NW FLOW
ALOFT. A SURFACE TROUGH EXTENDS FROM 29N90W SE TO 23N85W.
ISOLATED SHOWERS DOT THE GULF E OF THE TROUGH. A WEAK 1016 MB
HIGH IS OVER THE W GULF NEAR 26N92W LEAVING THE REMAINDER OF THE
GULF UNDER CLEAR SKIES TONIGHT. TROUGH IS EXPECTED TO LINGER
OVER THE CENTRAL GULF THROUGH FRI BEFORE DISSIPATING. HIGH
PRESSURE WILL BUILD NE OF THE REGION THROUGH THE WEEKEND. A
STRONG COLD FRONT WILL MOVE OFF THE TEXAS COAST MON MORNING AND
REACH FROM MOBILE BAY TO TAMPICO BY MON EVENING THEN REACH FROM
BIG BEND REGION OF FLORIDA TO W BAY OF CAMPECHE TUE.

CARIBBEAN SEA...
A BROAD UPPER RIDGE IN THE TROPICAL ATLC EXTENDS A RIDGE AXIS
FROM AN UPPER HIGH OVER BRAZIL ALONG THE N COAST OF SOUTH
AMERICA TO OVER COSTA RICA NEAR 11N84W GIVING THE CARIBBEAN
MAINLY SW TO W FLOW ALOFT. A SURFACE TROUGH IS ANALYZED FROM
21N82W ACROSS THE CAYMAN ISLANDS TO 10N78W. REMNANT MOISTURE
ACROSS THE N CARIBBEAN IS GENERATING SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS N OF LINE FROM THE WINDWARD
ISLANDS NEAR 12N61W 12N58W TO 15N78W AND WITHIN 75/90 NM OF LINE
FROM 16N78W TO OVER COSTA RICA. BROAD SURFACE RIDGE OVER THE W
ATLC WILL SHIFT E AND GRADUALLY COLLAPSE THROUGH FRI MAINTAINING
LIGHT TO MODERATE WINDS ACROSS MOST OF THE REGION.

ATLANTIC OCEAN...
AN UPPER TROUGH EXTENDS OVER THE FLORIDA PENINSULA INTO THE FAR
W ATLC W OF 77W. THE SURFACE TROUGH W OF THE BAHAMA ISLANDS
EXTENDS FROM 28N79W TO 23N80W. THE SURFACE TROUGH AND UPPER
TROUGH ARE INTERACTING AND GENERATING SCATTERED SHOWERS/
THUNDERSTORMS N OF 27N BETWEEN 77W-80W. AN UPPER RIDGE EXTENDS
FROM NEAR 20N67W TO BEYOND 32N72W PROVIDING DIFFLUENCE ALOFT TO
GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 21N-27N
BETWEEN 70W-78W. BROAD UPPER TROUGH COVERS THE CENTRAL ATLC N OF
20N BETWEEN 30W-55W SUPPORTING COLD FRONT THAT EXTENDS THROUGH
32N33W ALONG 24N38W TO 18N44W. A SHEAR LINE IS ANALYZED ALONG
FROM 18N44W ALONG 15N51W T 13N60W. AN UPPER RIDGE IS JUST TO THE
E EXTENDING FROM THE TROPICAL ATLC NEAR 16N28W TO BEYOND 32N21W
ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 300 NM
E OF THE FRONT N OF 21N. SURFACE RIDGE DOMINATES THE FAR E ATLC
N OF 18N E OF 27W ANCHORED BY A 1024 MB HIGH NEAR THE CANARY
ISLANDS. WEAKENING SURFACE RIDGE WILL SHIFT E AND GRADUALLY
COLLAPSE THROUGH FRI AND ALLOW A COLD FRONT TO BRUSH PAST THE
NORTHERN WATERS. THE SURFACE TROUGH W OF THE BAHAMAS WILL DRIFT
W-NW THROUGH FRI AS IT MOVES OVER FLORIDA AND COASTAL GEORGIA.
STRONG HIGH PRESSURE WILL BUILD NE OF THE AREA FRI THROUGH SUN.
A NEW COLD FRONT WILL APPROACH NW WATERS TUE.

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

$$
PAW





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