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000
AXNT20 KNHC 121759
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU DEC 12 2013

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.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE TROPICAL
ATLC NEAR 7N11W TO 4N16W WHERE THE ITCZ BEGINS AND CONTINUES
ALONG 2N31W ACROSS THE EQUATOR NEAR 42W TO INLAND OVER SOUTH
AMERICA. SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF ISOLATED
STRONG CONVECTION ARE WITHIN 120 NM N OF THE MONSOON TROF/ITCZ
BETWEEN 12W-18W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER TROUGH IS PUSHING S TO OVER THE SE GULF COAST
STATES SUPPRESSING THE UPPER RIDGE THAT REMAINS OVER THE NW
CARIBBEAN. THIS IS GIVING THE GULF WATERS NEAR ZONAL WESTERLY
FLOW ALOFT. THE BROAD UPPER TROUGH ABOVE HAS DEVELOPED A WEAK
LOW IN THE W ATLC WITH A WEAK COLD FRONT EXTENDING FROM THE W
ATLC NEAR 25N80W ALONG THE FLORIDA KEYS TO 23N86W WHERE THE
REMNANT DISSIPATING STATIONARY FRONT CONTINUES ALONG 22N92W TO S
MEXICO NEAR 18N94W. SCATTERED SHOWERS ARE WITHIN 45 NM OF COLD
FRONT. SURFACE RIDGE CONTINUES TO BUILD S IN WAKE OF THE FRONT
ANCHORED BY A PAIR OF 1037 MB HIGH OVER THE MIDDLE/LOWER
MISSISSIPPI VALLEY. DENSE LOW/MID CLOUDS WITH POSSIBLE ISOLATED
SHOWERS ARE WITHIN 75 NM ALONG THE COAST OF MEXICO S OF 26N W OF
95W. BROKEN TO OVER CAST LOW/MID CLOUDS WITH POSSIBLE ISOLATED
SHOWERS COVERS MOST OF THE REMAINDER OF THE GULF S OF 28N
LEAVING THE N GULF COAST UNDER CLEAR SKIES THIS AFTERNOON.
STATIONARY FRONT WILL DISSIPATE WHILE THE COLD FRONT MOVES S AND
DISSIPATES THROUGH FRI. SURFACE RIDGE WILL CONTINUE TO BUILD
ACROSS REGION THROUGH FRI. A SECOND COLD FRONT WILL MOVE INTO NW
GULF SAT AFTERNOON AND REACH FROM FAR W FLORIDA PANHANDLE TO
NEAR TAMPICO MEXICO LATE SAT THEN FROM CENTRAL FLORIDA TO
CENTRAL BAY OF CAMPECHE SUN AND FROM SW FLORIDA TO E BAY OF
CAMPECHE MON.

CARIBBEAN SEA...
THE UPPER RIDGE COVERS THE NW CARIBBEAN W OF 70W. A SURFACE
TROUGH REMAINS BENEATH THIS UPPER RIDGE JUST INLAND ALONG THE
COAST OF THE YUCATAN/BELIZE WITH SCATTERED TO HEAVY SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS S OF 20N TO THE COAST OF
HONDURAS AND GUATEMALA W OF 82W TO INLAND OVER THE
YUCATAN/BELIZE. A NARROW ELONGATED UPPER LOW IS OVER THE NE
CARIBBEAN WITH THE AXIS EXTENDING FROM NEAR GUADELOUPE IN THE
LEEWARD ISLANDS TO THE N COAST OF HISPANIOLA NEAR 70W. A BROAD
SURFACE TROUGH EXTENDS ACROSS THE CENTRAL CARIBBEAN FROM 16N73W
ACROSS HAITI INTO THE SW ATLC NEAR 20N73W TO 24N71W. THE
EASTERLY TRADE WINDS ARE GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 75 NM OF 16N FROM 67W-75W AND ARE BANKING
SCATTERED SHOWERS/THUNDERSTORMS OVER THE SW CARIBBEAN SW OF LINE
FROM 13N84W TO 9N80W. SURFACE RIDGE ACROSS CENTRAL ATLC WILL
SHIFT E THROUGH FRI. ANOTHER STRONG HIGH PRESSURE WILL MOVE OFF
THE E COAST THU NIGHT AND FRI THEN SHIFT E THROUGH THE WEEKEND
TO TIGHTEN THE PRESSURE GRADIENT AND INCREASE TRADE WINDS ACROSS
THE CARIBBEAN MON.

HISPANIOLA...
CURRENTLY SOME PASSING ISOLATED SHOWERS ARE MOVING ACROSS THE S
COAST OF THE ISLAND ASSOCIATED WITH THE ACTIVITY IN THE CENTRAL
CARIBBEAN. THE UPPER LOW OVER THE NE CARIBBEAN IS GIVING
HISPANIOLA NORTHERLY FLOW ALOFT AND COUPLED WITH DRY STABLE AIR
WILL KEEP SHOWERS TO A MINIMUM TODAY WITH SOME POSSIBLE ISOLATED
SHOWERS CLIPPING THE S COAST. THIS TREND WILL CONTINUE THROUGH
MON.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE SE CONUS DIPS INTO THE W ATLC
SUPPORTING A NEWLY DEVELOPED 1020 MB LOW THAT AT 11/1500 UTC IS
CENTERED NEAR 30N75W WITH A COLD FRONT EXTENDING ACROSS GRAND
BAHAMA ISLAND INTO THE GULF OF MEXICO NEAR 25N80W. SCATTERED
SHOWERS ARE WITHIN 45 NM OF COLD FRONT. A REMNANT STATIONARY
FRONT EXTENDS E FROM THE LOW ALONG 29N73W TO JUST E OF BERMUDA
NEAR 32N66W. AN UPPER RIDGE DOMINATES THE REMAINDER OF THE W
ATLC INTO THE CENTRAL ATLC W OF 40W ANCHORED NEAR 23N53W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF THE STATIONARY
FRONT. BROKEN TO OVERCAST LOW/MID CLOUDS WITH POSSIBLE ISOLATED
SHOWERS ARE WITHIN 120 NM N OF THE COLD FRONT. A SURFACE RIDGE
DOMINATES THE REMAINDER OF THE W ATLC AND CENTRAL ATLC FROM 20W-
70W ANCHORED BY A 1028 MB HIGH NEAR 28N39W. AN UPPER TROUGH
EXTENDS INTO THE FAR E ATLC NEAR 32N15W TO AN UPPER LOW NEAR
25N18W TO 20N25W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM
31N16W TO 19N20W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
WITHIN 150 NM OF THE UPPER LOW. W ATLC COLD FRONT WILL DRIFT SE
THROUGH THIS EVENING AND FRI REACHING FROM NEAR 32N60W TO
STRAITS OF FLORIDA FRI EVENING WHERE IT WILL WEAKEN AND
DISSIPATE THROUGH SAT. NEXT COLD FRONT WILL MOVE OFF THE NE
FLORIDA COAST SUN AND EXTEND FROM 32N72W TO SE FLORIDA EARLY MON.

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

$$
PAW