000 AXPZ20 KNHC 282128 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN JUL 28 2013 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 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 09N80W TO LOW PRES NEAR 09N96.5W 1010 MB TO 10N120W TO 12N127W TO 11N133W. THE ITCZ AXIS EXTENDS FROM 11N133W TO 11N140W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM S OF A LINE FROM 07N82W TO 09N93W...WITHIN 150 NM IN THE W QUADRANT OF THE LOW...WITHIN 150 NM S OF THE MONSOON TROUGH BETWEEN 109W AND 120W...WITHIN 60 NM S OF THE MONSOON TROUGH BETWEEN 120W AND 126W...AND ALSO FROM 07N TO 11N BETWEEN 120W AND 130W. IN ADDITION...SCATTERED MODERATE CONVECTION IS FROM 20N TO 24N E OF 110W...INCLUDING THE OPENING TO THE GULF OF CALIFORNIA...AND ALSO N OF 14N BETWEEN 93W AND 96W...INCLUDING THE GULF OF TEHUANTEPEC. ...DISCUSSION... A MID TO UPPER LEVEL SHORT WAVE TROUGH EXTENDING FROM THE NORTHERN CALIFORNIA COAST TO 25N135W IS SLOWLY DRIFTING SE... COMING INTO PHASE WITH AN UPPER LEVEL LOW NEAR 17N124W. STRONG TO GALE FORCE NORTHERLY WINDS ARE OCCURRING AT THE SURFACE W OF THE REDWOOD COAST OF CALIFORNIA. GLOBAL WAVE MODELS INDICATE SEAS TO 8 FT GENERATED BY THESE WINDS SPREADING S TO 30N DURING THE NEXT 24 HOURS...THEN SUBSIDING THROUGH 48 HOURS. THE SUBTROPICAL RIDGE IS RE-ESTABLISHING ITSELF ACROSS THE WATERS N OF 15N W OF 110W...IN THE WAKE OF TROPICAL STORM FLOSSIE...NOW WELL W OF THE AREA. FOR MORE INFORMATION ON FLOSSIE PLEASE SEE BULLETINS UNDER AWIPS/WMO HEADERS HFOTCMCP1/WTPA21 PHFO WHICH CAN BE ACCESSED ONLINE AT WWW.WEATHER.GOV/CPHC. ANY OUTER ASSOCIATED WINDS HAVE SHIFTED W OF 140W WHILE A SMALL AREA OF RELATED AND REMNANT SWELL TO 8 FT IS OVER THE FORECAST WATERS FROM 18N TO 24N W OF 138W. SEAS E OF 140W WILL SUBSIDE TO LESS THAN 8 FT THIS EVENING. THE MAIN FORECAST ISSUE ACROSS THE EASTERN PACIFIC CONCERNS THE DEVELOPMENT AND MOVEMENT OF AN AREA OF 1010 MB SURFACE LOW PRES CURRENTLY NOTED NEAR 09N96.5W ALONG THE MONSOON TROUGH. ASSOCIATED CONVECTION IS DESCRIBED IN THE SECTION ABOVE. THE MAIN UPPER SUPPORT FOR THE LOW APPEARS TO BE THE DIVERGENCE BETWEEN AN UPPER LOW CENTERED OVER SOUTHERN MEXICO NEAR 17.5N96.5W AND A RIDGE CENTERED OVER NICARAGUA. RECENT DATA FROM ASCAT SCATTEROMETER PASSES INDICATE FRESH TO STRONG WINDS WITHIN 75 NM IN THE N AND E QUADRANTS OF THE LOW...AS WELL AS WITHIN 75 NM S OF THE MONSOON TROUGH BETWEEN 96W AND 99W. LOWER LEVEL SUPPORT IS LIKELY DUE TO THE REMNANTS OF A TROPICAL WAVE THAT MIGRATED INTO THE EASTERN PACIFIC A COUPLE OF DAYS AGO. THE GFS MODEL REMAINS THE MOST AGGRESSIVE WITH DEVELOPING THE LOW WHILE THE MAJORITY OF OTHER GLOBAL MODELS REMAIN MORE CONSERVATIVE WITH DEVELOPMENT. A BLENDED SOLUTION WILL CONTINUE TO BE FOLLOWED FOR THE OFFICIAL FORECAST WITH FRESH TO STRONG WINDS CONTINUING TO ACCOMPANY THE LOW AS WELL AS SEAS OF 8-9 FT DURING THE NEXT 48 HOURS AS IT REACHES NEAR 12N105W BY TUE AFTERNOON. CROSS EQUATORIAL S TO SW SWELL RESULTING IN COMBINED SEAS OF 8-9 FT CONTINUES TO PROPAGATE ACROSS THE DEEP TROPICS TO THE S OF 09N BETWEEN 92W AND 127W. THE AFFECTED AREA IS FORECAST TO SHIFT N COVERING THE WATERS NEAR THE MONSOON TROUGH MERGING WITH THE AREA AROUND SURFACE LOW PRES DESCRIBED ABOVE BY 24 HOURS...AS WELL AS BETWEEN THE WATERS E OF THE GALAPAGOS AND 80W TO 06N. BY 48 HOURS THE SWELL WILL SUBSIDE TO LESS THAN 8 FT EXCEPT FOR THE AREA AROUND THE LOW. $$ LEWITSKY