000 AXPZ20 KNHC 102137 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI APR 10 2015 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE PRIMARY ITCZ AXIS WAS ANALYZED FROM 06N88W TO 03N96W TO 04N106W TO 02N115W TO 05N130W TO 02N140W. SCATTERED MODERATE TO STRONG WITHIN 90 NM EITHER SIDE OF THE PRIMARY AXIS BETWEEN 100W AND 110W. A SECONDARY ITCZ AXIS LIES S OF THE EQUATOR BUT HAS NO SIGNIFICANT DEEP CONVECTION ASSOCIATED WITH IT. ...DISCUSSION... A SURFACE RIDGE AXIS EXTENDS FROM A 1018 MB HIGH CENTER NEAR 29N121W THROUGH 23N120W TO 12N96W. RECENT ASCAT DATA SHOW AN AREA OF MODERATE TO FRESH TRADE WINDS SW OF THE RIDGE AXIS. THIS HIGH IS EXPECTED TO DISSIPATE SAT AS A COLD FRONT OVER THE NW PART OF THE AREA CONTINUES TO ENCROACH UPON IT. THE MAIN SUBTROPICAL HIGH HAS ALREADY REORGANIZED N OF THE HAWAIIAN ISLANDS...BUT THIS HIGH CENTER WILL ALSO RAPIDLY WEAKEN AS IT IS CHASED EASTWARD N OF THE AREA BY ANOTHER PROGRESSIVE COLD FRONT. THIS PATTERN SHOULD KEEP TRADE WINDS BELOW THE ADVISORY CRITERIA OF 20-25 KT THROUGH THE END OF THE FORECAST PERIOD SUN AFTERNOON. HOWEVER...WINDS SHOULD REMAIN A SOLID FRESH BREEZE OVER W WATERS THROUGH EARLY SAT AS A SURFACE TROUGH ENHANCES THE PRESSURE GRADIENT. THE FRESH BREEZE HERE IS HELPING TO KEEP SEAS TO 9 FT OVER WATERS W OF 120W WHERE NW...NE AND SW SWELL ARE COMBINING. SEAS ARE EXPECTED TO SUBSIDE BELOW 8 FT BY MIDDAY SAT AS THE PRESSURE GRADIENT DIMINISHES. THE TROUGH CURRENTLY STRETCHES FROM 11N131W TO 03N133W. IT LIES IN AN AREA OF DEEP LOW LEVEL MOISTURE AND BROAD SPEED DIFFLUENCE ALOFT THAT IS PROMOTING THE ENHANCEMENT OF DEEP CONVECTION. THIS CONVECTION IS DESCRIBED IN THE SECTION ABOVE. THESE CONDITIONS SHOULD CHANGE LITTLE THROUGH SAT. THE COLD FRONT ENCROACHING ON THE SUBTROPICAL HIGH STRETCHES FROM 30N127W TO 28N127W TO 23N140W. SHOWERS LIE PRIMARILY WITHIN 180 NM E OF THE FRONT N OF 26N AS WELL AS 150 NM S AND SE QUADRANTS OF THE 1012 MB SURFACE LOW NEAR 31N132W. THE 1902 UTC ASCAT-B PASS SHOWED NW WINDS TO NEAR GALE FORCE LIE N OF 28N BETWEEN 131W AND 137W. SEAS ARE IN THE 10-15 FT RANGE IN THIS AREA. ALOFT...THE LOW ASSOCIATED WITH THIS SYSTEM IS FILLING. LIGHTNING ACTIVITY HAS WANED. THE SYSTEM WILL BREAK DOWN AT THE SURFACE THROUGH SAT...WITH THE WINDS DIMINISHING BELOW ADVISORY CRITERIA BY SAT MORNING AND SEAS SUBSIDING BELOW 8 FT BY SUN MORNING. SPLIT FLOW OVER THE CENTRAL PACIFIC HAS DIRECTED A 130 KT JET ACROSS THE AREA FROM 19N140W THROUGH 22N125W TO MAZATLAN MEXICO. THIS JET IS PROPELLING WANING TROPICAL MOISTURE ALOFT ACROSS THE FORECAST AREA. A BAND OF CIRRUS LIES WITHIN 570 NM SE OF THE JET AXIS FROM THE OUTFLOW ASSOCIATED WITH THE SURFACE TROUGH OVER SW WATERS NORTHEASTWARD INTO THE SOUTHERN GULF OF CALIFORNIA AND BEYOND INTO NW MEXICO. THIS UPPER JET IS EXPECTED TO BECOME MORE ZONAL AS THE TROUGH ASSOCIATED WITH THE COLD FRONT OVER NW WATERS PUSHES E. THIS SHOULD SHIFT THE MAIN MOISTURE PLUME ALOFT SOUTHWARD INTO MAINLAND MEXICO. GAP WINDS... GULF OF PAPAGAYO...THE PRESSURE GRADIENT BETWEEN RIDGING OVER THE WESTERN CARIBBEAN AND THE ITCZ TO THE S IS CURRENTLY STRONG ENOUGH TO SUPPORT A PULSING FRESH TO STRONG NE BREEZE IN THE GULF OF PAPAGAYO WITH THE ASSISTANCE OF NOCTURNAL DRAINAGE FLOW. THE WINDS ARE BELOW ADVISORY CRITERIA AT THE MOMENT...BUT ARE EXPECTED TO RETURN IN THE EARLY MORNING HOURS SAT. WINDS WILL DROP OFF AGAIN SAT AFTERNOON. THE PRESSURE GRADIENT SHOULD THEN WEAKEN ENOUGH TO PREVENT WINDS FROM REACHING ADVISORY CRITERIA AGAIN THROUGH THE END OF THE FORECAST PERIOD SUN AFTERNOON. $$ SCHAUER