000 AXPZ20 KNHC 070328 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT NOV 07 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...TROPICAL LOWS... .LOW PRES IS CENTERED NEAR 12N91W ESTIMATED AT 1008 MB AND IS NOW MOVING SLOWLY N IN RESPONSE TO THE UPPER TROUGH IMMEDIATELY TO ITS W WHICH IS ALSO CONTRIBUTING BOTH SOUTHWESTERLY WIND SHEAR AND DRY AIR ENTRAINMENT. CURRENTLY SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS NOTED N OF 13N BETWEEN 91W AND 93W. .LOW PRES IS CENTERED NEAR 13N117W ESTIMATED AT 1010 MB. THE SURFACE LOW IS UNDER AN UPPER ANTICYCLONE AND THE ASSOCIATED UPPER DIFFLUENCE HAS BEEN ENHANCING CONVECTION...BUT OVERALL CONVECTION HAS BEEN DECREASING THE PAST FEW HOURS. CURRENTLY SCATTERED MODERATE TO STRONG CONVECTION IS NOTED WITHIN 30 NM OF 13N117W. ...ITCZ... THE ITCZ AXIS EXTENDS ALONG 11N85W TO 12N91W TO 08N98W TO 13N116W TO 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90 NM EITHER SIDE OF A LINE FROM 07N105W TO 11N110W. ...DISCUSSION... AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 11N112W WITH A SHORT WAVE RIDGE SHIFTING NE AND NOW CRESTING NEAR 21N107W. A TROPICAL RIDGE EXTENDS SW FROM THE ANTICYCLONE TO A SHARP CREST AT 11N127W WITH ANOTHER RIDGE EXTENDING SE FROM THE ANTICYCLONIC CENTER TO 06N98W. UPPER LEVEL DIFFLUENCE ENHANCED ITCZ CONVECTION EARLIER BETWEEN 132W AND 137W WITH THE DEBRIS STILL SPREADING NE ALONG THE W PERIPHERY OF THIS TROPICAL RIDGE... ROUGHLY WITHIN 150 NM EITHER SIDE OF LINE 08N136W TO 18N115W. DEBRIS MOISTURE FROM EARLIER CONVECTION NEAR A SURFACE LOW UNDER THE UPPER ANTICYCLONIC CENTER...DESCRIBED ABOVE...REMAINS WITHIN 120 NM OF 15N115W. UPPER DIFFLUENCE IS ALSO ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 104W AND 111W WITH THE DEBRIS MOISTURE SPREADING S BUT EVAPORATING ALONG 03N. AN UPPER RIDGE IS NOW AMPLIFYING NE INTO THE DISCUSSION AREA ALONG 27N140W TO 32N127W. AN UPPER CYCLONE IS NEAR 30N118W WITH A TROUGH EXTENDING SW TO 22N123W. DENSE UPPER MOISTURE IS OBSERVED OVER THE NE SEMICIRCLE OF THIS CYCLONE AND IS SPREADING NE ACROSS SOUTHERN CALIFORNIA AND ARIZONA AND NEW MEXICO. ELSEWHERE THE UPPER LEVELS APPEAR DRY N OF 20N W OF 117W. AN UPPER TROUGH EXTENDS S ALONG EASTERN OLD MEXICO INTO A SMALL MID TO UPPER CYCLONE AT 19N96W WITH THE TROUGH CONTINUING S TO A BASE OVER THE DEEP TROPICS AT 08N93W. THIS CYCLONE HAS DEEPENED WITH A SURFACE LOW OVER THE SW BAY OF CAMPECHE AT 19.5N95W AND ANALYZED AT 1010 MB. ISOLATED CONVECTION IS SLIGHTLY ENHANCED ALONG THE ITCZ JUST S OF THIS TROUGH BASE...BETWEEN 94W AND 100W WITH MOST OF THE DEBRIS MOISTURE EVAPORATING QUICKLY AS UPPER DRY AIR IS SWEEPING S ACROSS OLD MEXICO AND OVER THE TROPICAL PACIFIC N OF 09N BETWEEN 92W AND 107W. AN UPPER ANTICYCLONE IS OVER THE CENTRAL CARIBBEAN NEAR 14N74W WITH A RIDGE EXTENDING W TO NEAR 13N83W. SOME CONVECTION WAS ENHANCED ALONG THE PACIFIC COAST OF COLOMBIA BUT IS DISSIPATING AND THE DEBRIS MOISTURE IS SPREADING W AND NW ALONG THE UPPER RIDGE. AT THE LOW LEVELS A RIDGE IS BRIDGING SEVERAL DISSIPATING FRONTAL TROUGHS OVER THE NW WATERS AND CRESTING NEAR 15N110W. ALTHOUGH ASSOCIATED N WINDS ARE ONLY AT 15-20 KT IN THE WAKE OF THE FRONTS...THE FRONTS ARE ACCOMPANIED BY NW SWELLS THAT WILL CONTINUE TO BUILD TO NEAR 18 FT LATE SAT ALONG 30N BETWEEN 125W AND 135W. GAP WINDS... GALE FORCE WINDS ARE EXPECTED TO CONTINUE THROUGH THE GULF OF TEHUANTEPEC TONIGHT DIMINISHING BELOW GALE AFTER SUNRISE SAT MORNING. A RECENT SHIP REPORT OF 50 KT...AND THE DEVELOPMENT OF THE SURFACE LOW PRES IN THE BAY OF CAMPECHE...RESULTED IN RAISING THE INITIAL CONDITIONS TO 30 TO 45 KT. UNCERTAINTY CONTINUES IN THE FORECAST AS THE STRENGTH AND POSITION OF LOW PRES IN THE BAY OF CAMPECHE...THE PERSISTENT LOW PRES NEAR 12N91W THAT IS NOW DRIFTING N...AND TROPICAL DEPRESSION IDA IS NOW OVER THE EASTERN GULF OF HONDURAS AND IS FORECAST TO MOVE NORTHWARD AND STRENGTHEN. DEPENDING ON THE ORIENTATION OF THE LOW PRES CENTERS N OF THE AREA...ANOTHER N SURGE MAY OCCUR AS EARLY AS SUN IN THE GULF OF TEHUANTEPEC OR THE LOW POSITIONS MAY ACTUALLY IMPEDE THE N FLOW THROUGH THE ISTHMUS OF TEHUANTEPEC. $$ NELSON