000 AXNT20 KNHC 051136 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST WED DEC 05 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE FAR E TROPICAL ATLC NEAR 8N13W TO 8N15W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 6N21W 6N35W 9N52W TO SOUTH AMERICA NEAR 9N61W. NUMEROUS TO SCATTERED STRONG CONVECTION IS FROM 3N-7N BETWEEN 25W-31W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 120 NM N OF THE ITCZ BETWEEN 21W-25W AND WITHIN 120 NM S OF THE ITCZ BETWEEN 31W-33W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM N OF THE ITCZ BETWEEN 16W-21W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 75 NM OF LINE FROM THE COAST OF LIBERIA NEAR 6N10W TO 3N16W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 5N-9N BETWEEN 40W-43W. ...DISCUSSION... GULF OF MEXICO... A NARROW UPPER TROUGH EXTENDS INTO THE GULF FROM OVER LOUISIANA TO NEAR 22N95W SUPPORTING A COLD FRONT THAT AT 05/0900 UTC EXTENDS ACROSS PORT ARTHUR TEXAS ALONG 29N94W WHERE IT BECOMES STATIONARY TO A NEWLY DEVELOPED 1019 MB LOW ALONG THE COAST NEAR BROWNSVILLE THEN CONTINUES AS A COLD FRONT SW INTO NE MEXICO. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 45/60 NM OF LINE FROM 26N94W TO NE MEXICO NEAR MATAMOROS AND WITHIN 45 NM ALONG THE COAST OF MEXICO N OF TAMPICO. A WEAK 1018 MB LOW IS OVER LAKE PONTCHARTRAIN WITH A SURFACE TROUGH EXTENDING INTO THE GULF TO 25N93W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 180 NM E OF THE TROUGH WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS W OF THE TROUGH TO THE ABOVE FRONT. AN UPPER RIDGE EXTENDS ALONG 80W FROM CUBA TO BEYOND 32N COVERING THE FAR E GULF. THE SURFACE RIDGE IS SHIFTING E AHEAD OF THE FRONT ANCHORED BY A PAIR OF 1025 MB HIGHS...ONE IS LOCATED NEAR 33N72W AND THE SECOND ALONG THE COAST OF GEORGIA/SOUTH CAROLINA BORDER. ISOLATED SHOWERS ARE OVER THE SE GULF FROM 23N-26N E OF 87W ACROSS S FLORIDA AND THROUGH THE STRAITS OF FLORIDA. FRONT WILL STALL OVER THE W/CENTRAL GULF WED AND DISSIPATE THROUGH THU. HIGH PRESSURE WILL BUILD ACROSS THE REGION FRI THROUGH THE WEEKEND. CARIBBEAN SEA... A BROAD UPPER RIDGE IN THE TROPICAL ATLC EXTENDS A RIDGE AXIS ALONG THE N COAST OF SOUTH AMERICA TO OVER COSTA RICA NEAR 10N84W GIVING THE CARIBBEAN MAINLY SW TO W FLOW ALOFT. MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR ALOFT DOMINATES MOST OF THE CARIBBEAN THIS MORNING. LIGHT TO MODERATE NE TO E TRADE WINDS ACROSS THE CARIBBEAN CONTINUE TO BANK SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM ALONG THE COAST OF E HONDURAS TO W PANAMA BETWEEN 80W-84W. A SHEAR LINE IS ANALYZED FROM THE CENTRAL ATLC NEAR 17N60W BETWEEN THE LEEWARD AND WINDWARD ISLANDS TO 15N73W GENERATING SCATTERED SHOWERS WITHIN 120 NM N OF THE SHEAR LINE. THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY CLEAR SKIES THIS MORNING. BROAD SURFACE RIDGE OVER THE W ATLC WILL MAINTAIN THE TRADE WINDS ACROSS MOST OF THE REGION WITH GRADUALLY DIMINISHING FRESH TO STRONG WINDS IN THE NW CARIBBEAN AND ATLC PASSAGES THROUGH WED. THE PRESSURE GRADIENT WILL WEAKEN THU AND FRI AND INCREASE IN THE CENTRAL CARIBBEAN OVER THE WEEKEND AS HIGH PRESSURE REBUILDS TO THE N. ATLANTIC OCEAN... AN UPPER RIDGE COVERS THE FAR E GULF INTO THE FAR W ATLC W OF 70W. A WEAKENING SURFACE RIDGE DOMINATES THE W ATLC ANCHORED BY A PAIR OF 1025 MB HIGH...ONE IS LOCATED NEAR 33N72W AND THE SECOND ALONG THE COAST OF GEORGIA/SOUTH CAROLINA BORDER. THE EASTERLY SURFACE FLOW OVER THE FAR W ATLC IS GENERATING SCATTERED SHOWERS FROM 26N-29N W OF 78W TO OVER FLORIDA. A SURFACE TROUGH IS JUST E OF THE BAHAMA ISLANDS EXTENDING FROM 28N74W TO 22N73W. AN UPPER TROUGH EXTENDS INTO THE CENTRAL ATLC THROUGH 32N51W TO 23N51W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 31N36W ALONG 25N45W THROUGH A 1010 MB LOW NEAR 24N51W TO 17N60W WHERE A SHEAR LINE CONTINUES INTO THE CARIBBEAN NEAR THROUGH THE LEEWARD/WINDWARD ISLANDS. AN UPPER RIDGE IS TO THE E EXTENDING FROM 20N40W TO BEYOND 32N32W PROVIDING DIFFLUENCE ALOFT TO GENERATE DENSE CLOUD COVER WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 20N TO BEYOND 32N BETWEEN 35W-47W. AN UPPER TROUGH IS WELL N OF THE DISCUSSION AREA SUPPORTING A COLD FRONT THAT EXTENDS TO 31N36W. A SURFACE RIDGE DOMINATES THE REMAINDER OF THE E ATLC N OF 14N E OF 30W ANCHORED BY A 1028 MB HIGH NE OF MADEIRA ISLANDS. FRESH NE WINDS S OF 27N WILL LINGER EVEN AFTER THE HIGH PRESSURE N OF THE AREA WEAKENS AND SHIFTS EAST TODAY. A TROUGH JUST E OF THE BAHAMAS WILL AMPLIFY AS IT DRIFTS W INTO FLORIDA THROUGH FRI. A WEAK COLD FRONT WILL BRUSH PAST THE N WATERS WED THROUGH THU. STRONG HIGH PRESSURE WILL BUILD NE OF THE AREA THU NIGHT THROUGH SUN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW