000 AXPZ20 KNHC 212149 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT FEB 21 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 2100 UTC. ...SPECIAL FEATURES... NW WATERS GALE WARNING...A 968 MB STORM SYSTEM LOCATED N OF THE HAWAIIAN ISLANDS AND CENTERED NEAR 34N159W THIS AFTERNOON IS PRODUCING HURRICANE FORCE WINDS WELL NW OF THE AREA. THIS SYSTEM WILL MOVE NORTHEASTWARD AND CROSS 150W LATE MON AS IT GRADUALLY WEAKENS. THIS VERY LARGE AND COMPLEX SYSTEM WILL DRAG A COLD FRONT INTO THE FAR NW CORNER OF THE DISCUSSION AREA OVERNIGHT MONDAY...WITH STRONG SOUTHERLY WINDS AHEAD OF THE FRONT EXPECTED TO INCREASE TO GALE FORCE ACROSS THE WATERS N OF 28N W OF 138W MONDAY EVENING. THIS GALE EVENT WILL BE SHORT LIVED AS THESE STRONG TO GALE FORCE WINDS LIFT OUT OF THE AREA TO THE N OVERNIGHT MONDAY. ADDITIONALLY...THIS POWERFUL SYSTEM WILL GENERATE EXTREMELY LARGE NW SWELL BEHIND THE COLD FRONT. SEAS ARE EXPECTED TO BUILD IN EXCESS OF 20 FT ACROSS THE NW WATERS BY EARLY TUE MORNING. THE LEADING EDGE OF THE SWELL WILL PROPAGATE E AND SE ACROSS THE DISCUSSION AREA THROUGHOUT THE ENTIRE WORK WORK. LOOKING AHEAD...THIS VERY LARGE NW SWELL WILL STRONGLY IMPACT THE WEST COAST OF THE U.S. AND BAJA CALIFORNIA EARLY WED THROUGH THU. ...INTERTROPICAL CONVERGENCE ZONE... THE ITCZ AXIS WAS ANALYZED FROM 05N88W TO 01N98W TO 02N109W TO 02N120W TO 03N125W TO 02N140W. NO SIGNIFICANT DEEP CONVECTION WAS NOTED NEAR THE AXIS. ...DISCUSSION... THE PATTERN OVER THE EASTERN AND CENTRAL NORTH PACIFIC HAS BECOME AMPLIFIED. SUBTROPICAL HIGH PRES IS BUILDING AT THE SURFACE OVER N WATERS...WITH 1027 MB HIGH PRES ANALYZED NEAR 32N127W. A RIDGE AXIS EXTENDS SW FROM THE HIGH TO 24N140W. SCATTEROMETER DATA SHOWS PATCHES OF FRESH TO STRONG NE TRADE WINDS IN THE AREA FROM 06N-19N BETWEEN 119W-134W. THE STRONG SUBTROPICAL HIGH IS ALSO FORCING A TIGHT PRES GRADIENT ALONG THE W COAST OF BAJA CALIFORNIA WHERE SCATTEROMETER DATA SHOWS A FRESH TO STRONG N-NW BREEZE WITHIN 150 NM OF THE COAST N OF 25N. THE FRONT DISCUSSED IN THE SPECIAL FEATURES SECTION WILL SQUEEZE THE SUBTROPICAL HIGH WELL NORTHWARD BY MON...CAUSING TRADE WINDS AND WINDS OFF THE W COAST OF BAJA CALIFORNIA TO DIMINISH BELOW THE ADVISORY CRITERIA OF 20-25 KT BY MON AFTERNOON. GAP WINDS... GULF OF CALIFORNIA...N-NW WINDS ARE EXPECTED TO REACH A FRESH TO STRONG BREEZE ACROSS THE GULF OF CALIFORNIA FROM 23N-28N THIS EVENING AS HIGH PRES BUILDS OVER THE GREAT BASIN WHILE PRESSURES FALL OVER CENTRAL MEXICO. THE TIGHTEST PRES GRADIENT WILL GRADUALLY SHIFT NORTHWARD IN THE GULF BY MON EVENING...WITH WINDS OVER ADVISORY CRITERIA EXPECTED FROM 25N-29N INTO EARLY TUE BEFORE DIMINISHING. SEAS SHOULD BUILD TO 8 FT OVERNIGHT MON NIGHT IN THE SOUTH-CENTRAL PORTION OF THIS AREA UNDER PERSISTENT STRONG WINDS WITH A LONG FETCH. GULF OF TEHUANTEPEC...THE PRES GRADIENT BETWEEN HIGH PRES TO THE NORTH AND RELATIVE LOW PRES FARTHER SOUTH IN THE DEEP TROPICS IS WEAKENING ACROSS THE ISTHMUS OF TEHUANTEPEC...BUT IT IS STILL BELIEVED TO BE SUPPORTING MAXIMUM SUSTAINED WINDS TO 25 KT IN THE GULF OF TEHUANTEPEC S OF 14N. THIS SHOULD BE THE LAST GASP OF WINDS OVER ADVISORY HERE THROUGH THE END OF THE FORECAST PERIOD ON TUE AFTERNOON...WITH WINDS EXPECTED TO DIMINISH BY SUNSET. GULF OF PAPAGAYO...THE PRES GRADIENT BETWEEN HIGH PRES OVER THE NW CARIBBEAN AND LOWER PRES TO THE SW CONTINUES TO DRIVE FUNNELING WINDS ACROSS SOUTHERN NICARAGUA AND NORTHERN COSTA RICA...INCLUDING INTO THE GULF OF PAPAGAYO. WINDS HAVE DIMINISHED TO A FRESH TO STRONG BREEZE THIS AFTERNOON. NOCTURNAL DRAINAGE FLOW SHOULD INCREASE WINDS TO NEAR GALE FORCE EARLY MON MORNING AND THEN DIMINISH TO BELOW ADVISORY CRITERIA AFTER SUNRISE MON AS THE PRES GRADIENT ACROSS CENTRAL AMERICA SLACKENS. SWELL FROM THE GULF OF TEHUANTEPEC HAS MIXED WITH THAT FROM THE GULF OF PAPAGAYO TO CREATE A LARGE SWATH OF SEAS IN THE 8-9 FT RANGE GENERALLY FROM 03N-11N BETWEEN 94W-110W. THESE CONDITIONS WILL PERSIST INTO TONIGHT AS NW AND SW SWELL CONTRIBUTE TO THE COMBINED SEAS HERE. THIS AREA WILL SHRINK WESTWARD BEGINNING EARLY MON AND SUBSIDE BELOW 8 FT BY MON EVENING. GULF OF PANAMA...WEAKENING RIDGING N OF THE AREA HAS LOOSENED THE PRES GRADIENT ACROSS THE GULF OF PANAMA THIS AFTERNOON. FRESH TO STRONG N-NE WINDS WITH SEAS TO 8 FT ARE EXPECTED TO PERSIST GENERALLY FROM 04N-07N BETWEEN 79W-81W THROUGH SUNRISE MON BEFORE DIMINISHING AS THE HIGH PRES OVER THE NW CARIBBEAN WEAKENS. $$ SCHAUER