000 AXPZ20 KNHC 110236 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT APR 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE ITCZ AXIS WAS ANALYZED FROM 06N87W TO 05N91W TO 05N102W TO 03N115W TO 05N130W. SCATTERED MODERATE CONVECTION WAS WITHIN 150 NM N AND 210 NM S OF THE AXIS BETWEEN 105W-110W. A TROUGH LIES W OF THE AXIS FROM 12N131W TO 05N134W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 330 NM E AND 180 NM W OF THE TROUGH. ...DISCUSSION... A SURFACE RIDGE AXIS EXTENDS FROM A 1018 MB HIGH CENTER NEAR 28N120W THROUGH 17N108W TO 13N96W. 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 EVENING. HOWEVER...WINDS SHOULD REMAIN A SOLID FRESH BREEZE OVER W WATERS THROUGH EARLY SAT AS A SURFACE TROUGH N OF THE ITCZ OVER W WATERS 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 SURFACE TROUGH CURRENTLY STRETCHES FROM 12N131W TO 05N134W. 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 30N126W TO 25N129W TO 21N140W. SHOWERS LIE PRIMARILY WITHIN 180 NM E OF THE FRONT N OF 24N AS WELL AS 210 NM S AND SE QUADRANTS OF THE 1011 MB SURFACE LOW NEAR 29N131W. THE 1902 UTC ASCAT-B PASS SHOWED WINDS TO NEAR GALE FORCE WITHIN 180 NM W SEMICIRCLE. SINCE THEN...WINDS HAVE LIKELY COME DOWN A NOTCH. SEAS ARE IN THE 10-14 FT RANGE IN THIS AREA. ALOFT...THE LOW ASSOCIATED WITH THIS SYSTEM IS FILLING. THE SYSTEM WILL BREAK DOWN AT THE SURFACE THROUGH SAT...WITH THE WINDS DIMINISHING BELOW ADVISORY CRITERIA OVERNIGHT AND SEAS SUBSIDING BELOW 8 FT BY SUN MORNING. SPLIT FLOW OVER THE CENTRAL PACIFIC HAS DIRECTED A 125 KT JET ACROSS THE AREA FROM 19N140W THROUGH 22N125W TO GUAYMAS MEXICO. THIS JET IS PROPELLING WANING TROPICAL MOISTURE ALOFT ACROSS THE FORECAST AREA. A BAND OF CIRRUS LIES WITHIN 480 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