000 AXPZ20 KNHC 060256 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON AUG 06 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0115 UTC. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS FROM 1008 MB LOW PRES NEAR 12N106W TO 17N105W. SCATTERED MODERATE TO ISOLATED STRONG WAS WITHIN 90 NM OF THE CENTER EXCEPT 0 NM IN THE SE QUADRANT. SCATTERED MODERATE CONVECTION WAS ELSEWHERE WITHIN 75 NM ON EITHER SIDE OF THE WAVE FROM 12N TO 16N. FURTHER DEVELOPMENT OF THE LOW PRES SYSTEM IS POSSIBLE AS IT CONTINUES NW AROUND 10-15 KT. THE LOW MAY BECOME A TROPICAL CYCLONE WITHIN THE NEXT 48 HOURS. A TROPICAL WAVE EXTENDS FROM 10N128W TO 17N129W. THIS WAVE IS MOVING W AT 10 KT. UPPER LEVEL CONFLUENCE AND 20-30 KT NORTHERLY WINDS ALOFT HAVE MOVED OVER THE WAVE...SQUELCHING ANY SIGNIFICANT DEEP CONVECTION. WHILE THE CONVECTION HAS WANED...THE PRES GRADIENT BETWEEN THE SURFACE TROUGHING ASSOCIATED WITH THE WAVE AND THE SUBTROPICAL RIDGE SHOULD BE STRONG ENOUGH FOR FRESH TO STRONG WINDS TO BUILD NEAR THE WAVE OVER THE NEXT FEW DAYS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N78W TO 10N85W TO 10N100W TO 09N106W TO 10N122W. THE ITCZ AXIS WAS ANALYZED FROM 10N130W TO 09N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS FROM 06N TO 10N BETWEEN 90W AND 98W...FROM 05N TO 08N BETWEEN 84W AND 90W...AND WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 107W AND 111W. ...DISCUSSION... A WEAK SUBTROPICAL RIDGE EXTENDS OVER N WATERS WITH 1021 MB HIGH PRES CENTERED NEAR 31N131W. THE RIDGE WILL SLOWLY BUILD BEGINNING MON AS THE SUBTROPICAL HIGH CONSOLIDATES NW OF THE FORECAST AREA. LIGHT TO MODERATE WINDS ARE CURRENTLY UNDERNEATH THIS RIDGE ACROSS THE WATERS N OF THE MONSOON TROUGH/ITCZ AXIS...WITH MODERATE TO FRESH WINDS FOUND NEAR THE AFOREMENTIONED TROPICAL WAVES. THE PRES GRADIENT BETWEEN THE MONSOON TROUGH/ITCZ AND THE SE PACIFIC SUBTROPICAL HIGH IS SUPPORTING MODERATE TO FRESH SOUTHERLY FLOW W OF 95W AS OBSERVED BY THE MOST RECENT ASCAT PASSES. SWELL PERIODS REMAIN ABOVE 18 SECONDS IN THE SOUTHERN GULF OF CALIFORNIA AND ALONG THE CENTRAL AND NORTHERN PACIFIC COAST OF BAJA CALIFORNIA NORTE. THIS CROSS-EQUATORIAL SOUTHERLY SWELL TRAIN HAS IMPACTED THE ENTIRE COASTLINE WITHIN THE FORECAST AREA OVER THE PAST FEW DAYS. THIS SWELL IS BEGINNING TO SUBSIDE...BUT WILL CONTINUE TO PRIMARILY IMPACT THE COASTLINE OF MEXICO OVERNIGHT TONIGHT PRODUCING DANGEROUS SURF AND RIP CURRENTS AT THE BEACHES. HIGHEST ASSOCIATED SIGNIFICANT WAVE HEIGHTS ARE ACROSS THE S CENTRAL WATERS WITH SEAS TO 8 FT. THE SWELL WILL GRADUALLY DECAY MON AND TUE WITH SEAS SUBSIDING TO LESS THAN 8 FT BY MON AFTERNOON. AN ANTICYCLONE OVER NEW MEXICO EXTENDS A RIDGE SOUTH OF THE UPPER LOW NEAR 22N118W TO ANOTHER ANTICYCLONE CENTERED NEAR 18N136W. DIFFLUENCE ALONG THE EASTERN PORTION OF THIS RIDGE AXIS HAS ENHANCE THE CONVECTION ALONG THE SIERRA MADRE OCCIDENTALS THIS EVENING. STRONGER UPPER DIFFLUENCE CAN BE FOUND S OF THE RIDGE AXIS OVER THE TROPICAL WAVE ALONG 105W/106W WHERE WEAK SOUTHEASTERLY FLOW LIES NEAR THIS RIDGE AXIS AND A 40 KT NE WINDS CAN BE FOUND S OF 07N. BROAD DIFFLUENCE ALOFT IS ALSO ENHANCING THE DEEP CONVECTION FOUND BETWEEN 85W-100W...WHERE THE PRECIPITABLE WATER VALUES ARE HIGHEST WITHIN THE FORECAST AREA. GAP WINDS...FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED TO BEGIN IN THE GULF OF TEHUANTEPEC BY MON MORNING AND ARE FORECAST TO PERSIST AT LEAST THROUGH THE END OF THE FORECAST PERIOD ON TUE EVENING. THIS GAP WIND EVENT WILL BE INDUCED BY RELATIVELY HIGHER SURFACE PRESSURES OVER THE SW GULF OF MEXICO AHEAD OF ATLANTIC TROPICAL STORM ERNESTO AND LOWER PRES ASSOCIATED WITH THE MONSOON TROUGH WHICH WILL BE DRIFTING NORTHWARD AS ERNESTO APPROACHES CENTRAL AMERICA AND THE YUCATAN. $$ SCHAUER