000 AXNT20 KNHC 291801 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON OCT 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... THE CENTER OF HURRICANE SANDY AT 29/1800 UTC IS NEAR 38.3N 73.1W. SANDY IS ABOUT 95 NM TO THE SOUTHEAST OF ATLANTIC CITY NEW JERSEY...AND ABOUT 150 NM TO THE SOUTH-SOUTHEAST OF NEW YORK CITY. SANDY IS MOVING NORTHWEST 24 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 94 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 80 KNOTS WITH GUSTS TO 100 KNOTS. PLEASE READ THE FORECAST/ADVISORY UNDER THE AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC...AND THE PUBLIC ADVISORY UNDER MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. MODERATE CONVECTION PERSISTS WITHIN 60 NM OF THE CENTER. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH THE COASTAL GUINEA-BISSAU NEAR 12N16W TO 08N18W TO 06N28W. THE ITCZ CONTINUES FROM 06N28W TO 08N41W...THEN FROM 0845W TO 07N58W. SCATTERED MODERATE CONVECTION IS NOTED FROM 07N TO 09N BETWEEN 20N AND 25N. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED 07N TO 10N BETWEEN 40W AND 43W. ...DISCUSSION... THE GULF OF MEXICO... A SHORT WAVE MID TO UPPER LEVEL TROUGH OVER THE LOWER MISSISSIPPI VALLEY IS ROUNDING THE BASE OF A BROAD LOW CENTERED OVER THE TENNESSEE VALLEY...LEAVING GENERALLY ZONAL FLOW ALOFT IN PLACE ACROSS THE GULF INTO TUE. RESIDUAL STRATOCUMULUS CLOUDS ARE SLOWLY DISSIPATING ACROSS THE EASTERN GULF...BEHIND A COLD FRONT THAT PASSED THROUGH THE GULF YESTERDAY DRIVEN BY THE BROAD NORTHERLY FLOW AROUND HURRICANE SANDY IN THE WESTERN ATLC. FRESH TO STRONG NW TO N WINDS PERSIST OVER THE FAR EASTERN GULF...BUT HAVE STARTED TO DIMINISH OVER MOST OF THE CENTRAL AND WESTERN GULF WATERS. AREAS OF SHOWERS WITH A FEW THUNDERSTORMS ARE ACTIVE IN THE BAY OF CAMPECHE ALONG A REMNANT BOUNDARY OF THE OLD FRONT...SUPPORTED IN PART BY CONVERGENT NORTHERLY FLOW AND MID TO UPPER LEVEL MOISTURE ORIGINATING FROM THE EASTERN PACIFIC. HIGH PRES WILL BUILD OVER THE NW GULF...THEN INTO THE CENTRAL GULF BY TUE...ALLOWING WINDS AND SEAS TO DIMINISH FROM W TO E. THE CARIBBEAN SEA... THE MAIN DRIVER OF WEATHER IN THE CARIBBEAN FOR THE PAST COUPLE OF DAYS HAS BEEN A BROAD UPPER TROUGH THAT WAS DIGGING THROUGH THE GULF OF MEXICO...THEN WRAPPING AROUND HURRICANE SANDY IN THE NW ATLC. AN ASSOCIATED COLD FRONT PENETRATED INTO THE FAR NW CARIBBEAN YESTERDAY...AND IS STARTING TO STALL AND DISSIPATE FROM CENTRAL CUBA TO THE GULF OF HONDURAS. THIS FEATURE SHOWS UP WELL ON VISIBLE SATELLITE IMAGERY...AND IS FOLLOWED BY MODERATE TO FRESH NW FLOW. A PORTION OF THE UPPER TROUGH BECAME CUT OFF OVER THE SW CARIBBEAN OVER THE PAST COUPLE OF DAYS. CLUSTERS OF SHOWERS AND TSTMS PERSIST OVER THE S CENTRAL CARIBBEAN THIS AFTERNOON...DRIVEN IN PART BY UPPER LEVEL DIVERGENCE BETWEEN THE UPPER LOW PRES AND AN UPPER ANTICYCLONE CENTERED E OF THE CARIBBEAN. BOUY OBSERVATIONS INDICATE THAT THE PREVAILING WINDS ARE STARTING TO CHANGE FROM MOSTLY W TO NW IN THE WAKE OF SANDY...TO A RETURN OF EASTERLY TRADES OVER THE EASTERN CARIBBEAN. IN FACT BUOY 42059 NEAR 15N68W IS SHOWING LIGHT SE FLOW...JUST E OF THE CONVECTION. THIS IS AN INDICATION THAT A WEAK SURFACE TROUGH MAY BE FORMING OVER THE CENTRAL CARIBBEAN. EXPECT WINDS OVER THE NW CARIBBEAN TO VEER MORE NE BETWEEN THE TROUGH AND HIGH PRES BUILDING OVER THE GULF OF MEXICO. THE ATLANTIC OCEAN... W OF 60W...WARNINGS HAVE BEEN DROPPED OVER THE AREA N OF 28N AS HURRICANE SANDY CONTINUES TO MOVE N. W WINDS WILL PERSIST NEAR GALE FORCE HOWEVER THROUGH LATE TODAY ESPECIALLY OFF NE FLORIDA. A COLD FRONT EXTENDING FROM 31N75W THROUGH THE CENTRAL BAHAMAS IS DISSIPATING CURRENTLY. HIGH PRES WILL BUILD W TO E S OF 25N...WITH FRESH TO STRONG W FLOW N OF 25N THROUGH LATE IN THE WEEK. SCATTERED LOW CLOUDS PERSIST IN THE COOL NW TO W FLOW. BETWEEN 30W AND 60W...A DEEP LAYER ANTICYCLONE PERSISTS NEAR 17N55W. TO ITS EAST...A MID LATITUDE MID TO UPPER LEVEL TROUGH IS MOVING E THROUGH 40W...BRIEFLY COMING IN PHASE WITH A DEEP LAYER TROUGH IN THE TROPICS ALONG 45W. AT THE SURFACE...AN ASSOCIATED COLD FRONT TROUGH EXTENDS FROM 31N33W TO 25N37W...WITH A TRAILING TROUGH FROM 20N45W...NEARLY IN PHASE WITH A GENERALLY STATIONARY TROUGH S OF 15N ALONG 40W. E OF 40W... A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 35N39W CYCLONIC CIRCULATION CENTER TO 26N40W. NORTHWESTERLY-TO-WESTERLY WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF 25N BETWEEN AND 50W. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 32N34W TO 25N39W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO STRONG TO THE NORTH OF 22N BETWEEN 25W AND 34W. BROKEN TO OVERCAST MULTILAYERED CLOUDS ISOLATED MODERATE TO LOCALLY STRONG CONVECTIVE PRECIPITATION ARE ELSEWHERE TO THE NORTH OF 17N BETWEEN 20W AND 50W. A LINE OF MODERATE CONVECTION PRECEDES THE FRONT...WITH MODERATE TO STRONG CONVECTION NEAR THE TROUGH S OF 15N ALONG 40W. W OF 30W CONVECTION HAS DIMINISHED FROM YESTERDAY OFF THE COAST OF AFRICA S OF THE CANARAY ISLANDS...AS A VIGOROUS SHORT WAVE DIGGING INTO THE REGION LIFTED TO THE NE AND WEAKENED. AN ASCAT PASS FROM 11 UTC INDICATED SOME CYCLONIC TURING PERSISTED...REGARDED TO BE ALONG THE MONSOON TROUGH. GLOBAL MODELS TO INCLUDE THE GFS AND ECMWF INDICATE A WEAK CIRCULATION MAY FORM OVER THE NEXT COUPLE OF DAYS ALTHOUGH SUPPORTING CONVECTION MAY BE LIMITED. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ CHRISTENSEN