000 AXPZ20 KNHC 062120 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2000 UTC. ...SPECIAL FEATURES... 1008 MB LOW PRES IS NEAR 13N109W WITH AN ATTENDANT TROPICAL WAVE EXTENDING N OF THE LOW TO 20N109W. THIS WAVE AND LOW ARE MOVING W-NW AROUND 10 KT. SCATTERED MODERATE CONVECTION WAS WITHIN 180 NM W OF THE WAVE S OF 17N AND WITHIN 360 NM E OF THE WAVE FROM 14N TO 16N. 20-25 KT WINDS ARE BELIEVED TO BE WITHIN 60 NM OF THE CENTER OF THE LOW. HOWEVER...THERE HAVE BEEN FEW SHIP OBSERVATIONS AND THE 1646 UTC ASCAT PASS JUST CLIPPED THE WESTERN SIDE OF THE CIRCULATION THIS AFTERNOON. OUTSIDE THE CIRCULATION...SEAS ARE TO 8 FT IN SUBSIDING SOUTHERLY SWELL AROUND THE LOW FROM 09N TO 16N BETWEEN 103W AND 111W BASED ON AN EARLIER JASON1 PASS. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR DEVELOPMENT...AND THIS LOW MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS ALONG 133W FROM 10N TO 17N. SIGNIFICANT DEEP CONVECTION ASSOCIATED WITH THE WAVE IS CONFINED TO NEAR THE WESTERN EDGE OF ITCZ FOUND JUST S OF THE WAVE. THIS CONVECTION IS DESCRIBED IN THE SECTION BELOW. 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 W CENTRAL WATERS DURING THE NEXT FEW DAYS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 07N78W TO 10N90W TO 09N99W TO 13N109W TO 10N115W TO 10N125W. THE ITCZ AXIS WAS ANALYZED FROM 10N125W TO 10N130W TO 09N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 45 NM N AND 60 NM S OF THE AXIS E OF 79W AS WELL AS WITHIN 120 NM S OF THE AXIS W OF 131W. WEAK LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 09N99W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS AROUND THE LOW FROM 06N TO 12N BETWEEN 96W AND 103W. ...DISCUSSION... A WEAK SUBTROPICAL RIDGE EXTENDS OVER N WATERS WITH 1023 MB HIGH PRES CENTERED NEAR 31N134W. THE RIDGE WILL BUILD THROUGH TUE AS THE SUBTROPICAL HIGH CONSOLIDATES NW OF THE FORECAST AREA AND SLOWLY BEGIN TO WEAKEN WED AS A COLD FRONT APPROACHES IT FROM THE NW. ASIDE FROM THE TROPICAL WAVE AND LOW DISCUSSED IN THE SPECIAL FEATURES SECTION...LIGHT TO MODERATE WINDS ARE CURRENTLY UNDERNEATH THIS RIDGE ACROSS THE WATERS N OF THE MONSOON TROUGH/ITCZ AXIS. MODERATE TO FRESH WINDS ARE EXPECTED TO BUILD NEAR THE TROPICAL WAVE ALONG 133W BY LATE TUE. AN ANTICYCLONE OVER NEW MEXICO EXTENDS A RIDGE NORTH OF THE UPPER LOW NEAR 20N121W TO ANOTHER ANTICYCLONE CENTERED NEAR 18N136W AND EXTENDS A SECOND RIDGE AXIS SOUTHWARD THROUGH THE MOUTH OF THE GULF OF CALIFORNIA TO S OF THE UPPER LOW NEAR 10N120W. DIFFLUENCE ASSOCIATED THIS SOUTHERN RIDGE AXIS CAN BE FOUND OVER THE TROPICAL WAVE AND LOW ALONG 109W. THIS WAVE IS ASSOCIATED WITH THE HIGHEST PRECIPITABLE WATER VALUES IN THE FORECAST AREA AND THE DIFFLUENCE ALOFT IS HELPING TO LIFT THIS MOISTURE AND SUSTAIN DEEP CONVECTION NEAR THE WAVE AND LOW. GAP WINDS...FRESH TO STRONG NORTHERLY WINDS ARE FUNNELING THROUGH CHIVELA PASS INTO THE GULF OF TEHUANTEPEC. THEY ARE FORECAST TO PERSIST THROUGH WED MORNING. THIS GAP WIND EVENT WAS INDUCED BY THE PRESSURE GRADIENT BETWEEN RELATIVELY HIGHER SURFACE PRESSURES OVER THE SW GULF OF MEXICO AHEAD OF ATLANTIC TROPICAL STORM ERNESTO AND LOWER PRESSURE WITH THE MONSOON TROUGH SOUTH OF TEHUANTEPEC WHICH WILL BE DRIFTING NORTHWARD BEFORE ERNESTO MOVES INTO THE YUCATAN PENINSULA EARLY WED. $$ SCHAUER