000 AXPZ20 KNHC 032113 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI AUG 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...TROPICAL WAVES... THE SOUTHERN END OF A TROPICAL WAVE OVER GUATEMALA CURRENTLY LIES ALONG 91W N OF 09N AND IS MOVING W AROUND 15 KT. SCATTERED MODERATE CONVECTION WAS FROM 04N TO 09N BETWEEN 85W AND 90W ON THE SE SIDE OF THE WAVE. WINDS ARE CURRENTLY A GENTLE BREEZE OR LESS NEAR THE WAVE. A TROPICAL WAVE LIES ALONG 104W FROM 09N TO 17N. THE WAVE IS MOVING W AROUND 5-10 KT. SCATTERED MODERATE CONVECTION WAS FROM 07N TO 10N BETWEEN 100W AND 107W...IN THE REGION CLOSEST TO THE MONSOON TROUGH...AS WELL AS ON THE NORTH END OF THE WAVE INTO MEXICO FROM 16N TO 19N BETWEEN 102W AND 106W. WINDS ARE ONLY AS STRONG AS A MODERATE BREEZE WITH THIS WAVE. THE 1608 UTC ASCAT PASS SUGGESTS THAT THE WAVE IS BECOMING POORLY DEFINED AT THE SURFACE. A TROPICAL WAVE STRETCHES FROM 17N121W TO 12N123W AND IS MOVING W AROUND 10 KT. SCATTERED MODERATE CONVECTION WAS FROM 12N TO 16N BETWEEN 117W AND 123W. THE CONVECTION IS PRIMARILY FOUND WHERE THE WAVE CROSSES A RIDGE AXIS ALOFT THAT EXTENDS FROM THE UPPER ANTICYCLONE CENTERED NEAR 15N113W. UPPER DIFFLUENCE ASSOCIATED WITH THE RIDGE AXIS IS ENHANCING THIS CONVECTION. PRECIPITABLE WATER IMAGERY STILL SHOWS PLENTIFUL LOW LEVEL MOSITURE NEAR THE WAVE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 09N83W TO 09N90W TO 13N97W TO 09N108W TO 13N120W TO 09N130W. ITCZ AXIS FROM 09N130W TO 10N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 150 NM S OF THE AXIS BETWEEN 108W AND 113W AND FROM 90 NM TO 240 NM SE OF THE AXIS BETWEEN 113W AND 120W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 120 NM N AND 150 NM S OF THE AXIS BETWEEN 123W AND 137W. ...DISCUSSION... THE 1032 MB SUBTROPICAL HIGH NEAR 42N143W IS FORECAST TO WEAKEN AS IT CONTINUES MOVING W OVER THE NEXT TWO DAYS...WEAKENING THE RIDGING OVER THE FORECAST AREA. THE BELT OF FRESH TO STRONG TRADE WINDS CURRENTLY FOUND N OF THE ITCZ AND W OF 135W WILL DIMINISH OVER THE FORECAST AREA BY SAT AFTERNOON. A STRONG SOUTH PACIFIC SUBTROPICAL RIDGE IS CURRENTLY IN PLACE AND IS FORCING A MODERATE TO FRESH SE BREEZE S OF THE MONSOONS TROUGH WITH THE STRONGEST WINDS FOUND S OF 06N BETWEEN 110W AND 120W ACCORDING TO THE 1750 UTC ASCAT PASS. CROSS-EQUATORIAL SOUTHERLY SWELL IS BEGINNING TO REACH THE COAST OF PANAMA AND COSTA RICA AND HAS MOVED AS FAR N AS 15N IN WATERS BETWEEN THE GALAPAGOS ISLANDS AND 125W. THE LEADING EDGE OF THIS SWELL HAS PERIODS IN EXCESS OF 20 SECONDS. IT WILL MOVE NORTHWARD ALONG THE CENTRAL AMERICAN AND SOUTHERN MEXICAN COAST TONIGHT AND INTO THE SOUTHERN GULF OF CALIFORNIA AND THE PACIFIC COAST OF BAJA CALIFORNIA SUR ON SAT BEFORE MAKING ITS WAY N ONTO THE CALIFORNIA COAST. INTERESTS ALONG THE COAST SHOULD BE AWARE OF THE POTENTIAL FOR HIGH SURF AND POSSIBLY SOME COMPLICATIONS ENTERING HARBORS AND INLETS. SWELL HEIGHTS TO 9 FT CAN BE EXPECTED AS FAR N AS 09N THROUGH SUN AFTERNOON. A SERIES OF WEAK ANTICYCLONES ALOFT CAN BE FOUND AT 16N98W... 15N113W AND 12N129W. UPPER DIFFLUENCE ALONG THE RIDGE AXIS STRINGING THESE ANTICYCLONES TOGETHER IS ENHANCING CONVECTION NEAR THE TROPICAL WAVES ALONG 104W AND NEAR 122W. THE WESTERN ANTICYCLONE IS ASSOCIATED WITH A BROAD REGION OF UPPER DIFFLUENCE ON ITS SOUTHERN EDGE WHICH LIES OVER THE HIGHEST PRECIPITABLE WATER VALUES OVER THE FORECAST AREA CONVERGED NEAR THE ITCZ W OF 123W. THE MONSOON TROUGH SHOULD REMAIN ACTIVE HERE OVER THE NEXT FEW DAYS AS THESE ENVIRONMENTAL CONDITIONS ARE EXPECTED TO SEE LITTLE CHANGE. THE SURFACE PRESSURE GRADIENT WILL INCREASE IN THE EVENING HOURS ALONG THE CENTRAL COAST OF BAJA CALIFORNIA OVER THE NEXT FEW DAYS AS DIURNALLY LOWER PRESSURE OVER MAINLAND MEXICO BUTTS UP AGAINST THE SUBTROPICAL RIDGE. THIS WILL BRIEFLY INCREASE THE WINDS TO A FRESH BREEZE IN THE REGION EACH EVENING. $$ SCHAUER