000 AXPZ20 KNHC 042133 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT AUG 04 2012 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2000 UTC. ...TROPICAL WAVES... THE TROPICAL WAVE THAT WAS ALONG 94W AT 1200 UTC CAN NO LONGER BE TRACKED WITH OBSERVATIONAL DATA. UPPER LEVEL CONFLUENCE ASSOCIATED WITH A TROUGH THAT EXTENDS FROM AN UPPER LOW IN THE GULF OF MEXICO THROUGH THE GULF OF TEHUANTEPEC TO 10N95W IS LIKELY SUPPRESSING CONVECTION. THESE CONDITIONS IN ADDITION TO A RELATIVE LACK OF AVAILABLE MOSITURE APPEAR TO HAVE TAKEN THEIR TOLL ON THE SYSTEM. THE TROPICAL WAVE PREVIOUSLY ANALYZED ALONG 107W HAS BEEN REPOSITIONED BASED ON VISIBLE AND PRECIPITABLE WATER SATELLITE DATA. THE WAVE LIES ALONG 101W FROM 08N TO 16N. SHIP DATA AND THE 1548 UTC ASCAT PASS SHOW WINDS ARE ONLY AS STRONG AS A MODERATE BREEZE WITH THIS WAVE. SCATTERED MODERATE CONVECTION CURRENTLY LIES FROM 08N TO 11N BETWEEN 98W AND 109W AND ISOLATED MODERATE CONVECTION CAN BE FOUND ELSEWHERE WITHIN 180 NM EITHER SIDE OF THE WAVE. CONVECTION HAS WANED SOMEWHAT SINCE EARLIER TODAY WHEN THE TROPICAL OVERSHOOTING TOPS PRODUCT FROM THE GOES-R PROVING GROUND SHOWED VIGOROUS CONVECTIVE ACTIVITY NEAR THE WAVE AND THE ADJACENT MONSOON TROUGH WITH A PLETHORA OF OVERSHOOTING TOPS NOTED. THIS WAVE IS FORECAST TO CONTINUE WESTWARD AT 5 TO 10 KT OVER THE NEXT FEW DAYS. A TROPICAL WAVE STRETCHES ALONG 123W FROM 10N TO 19N WITH WEAK LOW PRES ANALYZED ALONG THE WAVE NEAR 14N. THIS WAVE IS MOVING W AROUND 5 KT. THE 1726 UTC ASCAT PASS SHOWED FRESH NE TO E WINDS WITHIN 150 NM N QUADRANT OF THE LOW PRES CENTER. THIS LOW IS EXPECTED TO GRADUALLY WEAKEN ALONG THE WAVE OVER THE NEXT DAY OR SO AS IT ENCOUNTERS 20-30 KT NE SHEAR. ISOLATED MODERATE CONVECTION WAS FROM 07N TO 11N BETWEEN 121W AND 128W. THE PRECIPITABLE WATER VALUES ARE HIGHER NEAR THIS WAVE THAN ANYWHERE ELSE IN THE FORECAST AREA. WITH BOTH THE AVAILABLE MOISTURE EXPECTED TO DIMINISH AND THE SHEAR EXPECTED TO INCREASE OVER THE SYSTEM...CONVECTION SHOULD WANE SOMEWHAT NEAR THE WAVE OVER THE NEXT FEW DAYS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N78W TO 09N83W TO 09N95W THEN CONTINUES FROM 11N106W TO 11N120W. THE ITCZ AXIS WAS ANALYZED FROM 10N126W TO 09N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 45 NM EITHER SIDE OF THE AXIS E OF 80W...INCLUDING THE GULF OF PANAMA. ISOLATED MODERATE CONVECTION WAS FROM 06N TO 10N BETWEEN 82W AND 94W. SCATTERED MODERATE CONVECTION WAS WITHIN 90 NM N AND 180 NM S OF THE AXIS BETWEEN 113W AND 119W. ...DISCUSSION... THE 1031 MB SUBTROPICAL HIGH NEAR 41N146W IS FORECAST TO WEAKEN AS IT CONTINUES MOVING W OVER THE NEXT TWO DAYS...WEAKENING THE RIDGING OVER THE FORECAST AREA. TRADE WINDS HAVE DIMINISHED TO 20 KT OR LESS ACCORDING TO THE 1908 UTC ASCAT PASS...BUT NE SWELL WILL KEEP SEAS TO 8 FT IN THE REGION OF MODERATE NE TRADES FROM 10N TO 13N W OF 138W THROUGH THIS EVENING. THE LEADING EDGE OF A CROSS-EQUATORIAL SOUTHERLY SWELL TRAIN HAS REACHED AS FAR N AS THE SE GULF OF CALIFORNIA AND THE PACIFIC COAST OF BAJA CALIFORNIA SUR. THE LEADING EDGE OF THIS SWELL HAS PERIODS IN EXCESS OF 20 SECONDS. THIS SWELL CONTINUES TO IMPACT THE REMAINDER OF THE COASTLINE SOUTH OF THE GULF OF CALIFORNIA...BUT IS BEGINNING TO DIMINISH. STILL...INTERESTS ALONG THE COAST SHOULD BE AWARE OF THE POTENTIAL FOR HIGH SURF AND POSSIBLY SOME COMPLICATIONS ENTERING HARBORS AND INLETS. SWELL HEIGHTS TO 10 FT CAN BE EXPECTED AS FAR N AS 11N W OF THE GALAPAGOS ISLANDS INTO SUN...WITH SEAS OFFSHORE OF THE COASTLINE EXPECTED TO BE PRIMARILY IN THE 5-8 FT RANGE. SEAS WILL SUBSIDE CONSIDERABLY BY MON. ALOFT...A VAST RIDGE AXIS SPANS FROM AN ANTICYCLONE OVER THE MID MISSISSIPPI VALLEY SOUTHWESTWARD TO A TROUGH SNAKING OFF THE COAST OF MEXICO FROM 32N121W TO 25N117W TO 16N103W. THE RIDGE AXIS THEN CONTINUES FROM 25N121W TO 19N140W THEN W OF THE FORECAST AREA. A SECOND ANTICYCLONE LIES NEAR 15N109W AND EXTENDS A RIDGE AXIS OVER THE TROPICAL WAVE ALONG 123W TO 08N130W. THIS ANTICYCLONE AND RIDGE WILL WEAKEN OVER THE NEXT DAY OR SO. GAPS WINDS...NORTHERLY WINDS ARE EXPECTED TO INCREASE TO 20 TO 25 KT IN THE GULF OF TEHUANTEPEC BY EARLY MON MORNING AND PERSIST THROUGH THE END OF THE PERIOD MON AFTERNOON. $$ SCHAUER