000 AXNT20 KNHC 061753 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SUN JAN 06 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 1745 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS E TO W ALONG THE SOUTHERN COAST OF AFRICA FROM 05E TO 08W...THEN CONTINUES W-SW TO 03N18W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W-SW TO THE COAST OF S AMERICA AT 01S48W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ABOUT 240 NM S OF THE MONSOON TROUGH...ROUGHLY WITHIN 30 NM EITHER SIDE OF A LINE FROM 04N07E TO 01N01E TO 02N14W...AND A LINE FROM 02N23W TO 03N31W TO 04N36W TO 02N50W. SIMILAR CONVECTION IS NOTED ALONG THE EQUATOR BETWEEN 28W AND 35W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL SHORTWAVE TROUGH IS ADVANCING EASTWARD ACROSS EASTERN N AMERICA WITH SOUTHWESTERLY UPPER FLOW PRECEDING THE TROUGH ACROSS THE ENTIRE GULF OF MEXICO. A STATIONARY SURFACE FRONT EXTENDS W ACROSS FLORIDA AND THE GULF OF MEXICO ALONG 28N TO 91W...THEN TURNS S INTO A 1017 MB FRONTAL WAVE LOW AT 25N93W...WITH A COLD FRONT EXTENDING S FROM THE LOW TO THE EASTERN BAY OF CAMPECHE. BROKEN TO OVERCAST LOW TO MID LEVEL CLOUDS IS OBSERVED NW OF A LINE FROM THE FLORIDA BIG BEND TO THE BAY OF CAMPECHE. UPPER DIFFLUENCE IS ENHANCING SCATTERED MODERATE ISOLATED STRONG CONVECTION...WITH FREQUENT LIGHTNING... OVER THE CENTRAL GULF WATERS WITHIN 180 NM OF 26N89W. NORTHERLY WINDS W OF THE SURFACE LOW AND COLD FRONT ARE AT 20 TO 30 KT WITH THIS NORTHERLY FLOW CONTINUING S THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC...WHERE THE NORTHERLY FLOW IS AT GALE FORCE. THE LOW IS EXPECTED TO LIFT NE THIS AFTERNOON AND DISSIPATE TONIGHT WITH REMNANTS OF THE LIFTING N THROUGH THROUGH MON NIGHT. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONE IS OVER THE SUBTROPICAL ATLANTIC JUST N OF PUERTO RICA WITH AN UPPER RIDGE EXTENDING W-SW ACROSS THE NORTHERN CARIBBEAN TO A CREST OVER THE GULF OF HONDURAS. SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE NOTED OVER THE FAR WESTERN GULF OF HONDURAS AND BELIZE WITH THE RESULTANT DENSE DEBRIS MOISTURE ADVECTED N ALONG THE PERIPHERY OF THE UPPER RIDGE ACROSS THE YUCATAN CHANNEL AND WESTERN CUBA. ADDITIONAL UPPER MOISTURE...THOUGH NOT VERY DENSE...IS INDICATED OVER THE REMAINDER OF THE NW CARIBBEAN CONTINUING NE ACROSS CUBA AND THE CENTRAL BAHAMAS. OTHERWISE VERY DRY UPPER AIR ACCOMPANIES THE UPPER RIDGE...AND IS SUPPRESSING CONVECTION ACROSS THE CARIBBEAN SEA. AT THE LOW LEVELS FRESH TO STRONG EASTERLY TRADES ARE ADVECTING FAIR WEATHER CUMULUS ACROSS THE CARIBBEAN WITH SHOWERS ENHANCED OVER THE LARGER ISLANDS WITH ELEVATED TERRAIN. THESE EASTERLIES ARE AT MINIMAL GALE STRENGTH IN THE AREA FROM 11N TO 13N BETWEEN 73W AND 78W WITH SEAS 9 TO 14 FT...BUT EXPECTED TO DIMINISH BELOW GALE STRENGTH EARLY THIS AFTERNOON. ATLANTIC OCEAN... A LONGWAVE TROUGH DOMINATES THE CENTRAL N ATLANTIC WHILE SHORTWAVE UPPER RIDGES ARE NOTED OVER THE WESTERN AND EASTERN N ATLANTIC. THE WESTERN RIDGE ORIGINATES FROM AN UPPER ANTICYCLONE CENTERED JUST N OF PUERTO RICO. THIN UPPER MOISTURE IS STREAMING NE ACROSS THE BAHAMAS WHILE DENSE UPPER MOISTURE IS NOTED OVER THE NW PORTION OF THE DISCUSSION AREA. A SURFACE COLD FRONT STRETCHES FROM 31N35W TO 26N56W WHERE THE BOUNDARY BECOMES NEARLY STATIONARY TO 28N65W...WHERE THE FRONT HAS BEGUN MOVING N AS A WARM FRONT TO ACROSS FLORIDA ALONG 28N. LOCALLY BROKEN LOW AND MID LEVEL CLOUDS...WITH EMBEDDED SHOWERS...ARE OBSERVED WITHIN 90 NM N OF THE SURFACE FRONT WHILE FAIR WEATHER CUMULUS AND STRATOCUMULUS CLOUDS ARE OBSERVED ACROSS THE REMAINDER OF THE AREA W OF 35W WITH THESE CLOUDS MOVING W IN THE FRESH EASTERLY WINDS WELL TO THE S OF THE PREVIOUSLY MENTIONED SURFACE FRONT. SURFACE HIGH PRESSURE AT 1026 MB IS CENTERED N OF THE FRONT NEAR 31N58W AND IS EXPECTED TO SHIFT E ALONG 31N OVER THE NEXT 24 HOURS WITH A RIDGE EXTENDING W TO NEAR 28N78W. THE RIDGE WILL RETRACT E ALLOWING A COLD FRONT TO MOVE TO ENTER THE NW WATERS TONIGHT WHILE LIFTING REMNANTS OF THE CURRENT FRONT N. AN UPPER TROUGH EXTENDS INTO THE AREA ALONG 32N35W TO 21N44W WITH DENSE UPPER MOISTURE OBSERVED UNDER A SHORTWAVE RIDGE E OF THE E OF THIS TROUGH TO 18W. A SECOND UPPER TROUGH EXTENDS SW ACROSS NW AFRICA ALONG 30N03E TO 20N17W CONTINUING SW TO BASE NEAR 07N32W AND IS ACCOMPANIED BY DRY UPPER AIR WITHIN 120 NM OF THE TROUGH AXIS. A BROAD RIDGE IS NOTED OVER THE FAR EASTERN TROPICAL ATLANTIC AND IS ADVECTING DENSE DEBRIS MOISTURE NE ACROSS WITHIN 540 NM EITHER SIDE OF A LINE FROM 09N14W TO TO BEYOND 21N10E. DRY UPPER AIR IS NOTED OVER THE TROPICAL ATLANTIC FROM 10N TO 22N BETWEEN 18W AND 28W WITH MOSTLY CLEAR SKIES INDICATED WHILE LOCALLY BROKEN STRATOCUMULUS IS STREAMING SW WITHIN 150 NM EITHER SIDE OF A LINE FROM 22N28W TO 10N36W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NELSON