000 AXPZ20 KNHC 221018 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN FEB 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... GALE WARNING...A LARGE AND POWERFUL 964 MB STORM SYSTEM LOCATED N OF THE HAWAIIAN ISLANDS AND CENTERED NEAR 37N155W TONIGHT IS PRODUCING GALE FORCE WINDS OUTWARD TO 800 NM OF THE CENTER... WITH HURRICANE FORCE WINDS ACROSS PORTIONS OF THIS SYSTEM AND WELL NW OF THE AREA. THIS STORM WILL MOVE NORTHEASTWARD AND CROSS 150W THIS AFTERNOON 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 TONIGHT...WITH STRONG SOUTHERLY WINDS AHEAD OF THE FRONT EXPECTED TO INCREASE TO GALE FORCE ACROSS THE WATERS N OF 28N W OF 138W LATE THIS AFTERNOON. THIS GALE EVENT WILL BE SHORT LIVED AS THESE STRONG TO GALE FORCE WINDS LIFT OUT OF THE AREA TO THE N OVERNIGHT TONIGHT. 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 LATE THU...AND THE REST OF MAINLAND MEXICO AND CENTRAL AMERICA THU THROUGH SAT. ...INTERTROPICAL CONVERGENCE ZONE... THE ITCZ EXTENDS FROM 04N90W TO 03.5N96W TO 02N120W TO BEYOND00N140W. WIDELY SCATTERED MODERATE TO STRONG CONVECTION NOTEDWITHIN 120 NM N OF ITCZ BETWEEN 90W AND 95W. ...DISCUSSION... THE UPPER LEVEL PATTERN OVER THE EASTERN AND CENTRAL NORTH PACIFIC HAS BECOME AMPLIFIED DURING THE PAST 24 HOURS. A 1027 MB SUBTROPICAL HIGH PRES WAS ANALYZED AT THE SURFACE JUST N OF THE AREA NEAR 34N128W. A RIDGE AXIS EXTENDS SW FROM THE HIGH TOSEOFTHE BIG ISLAND OF HAWAII NEAR 18N151W. RECENT SCATTEROMETER DATA SHOWED ZONES OF FRESH TO STRONG NE TRADE WINDS IN THE AREA FROM 06N-22N BETWEEN 118W-135W. THE STRONG SUBTROPICAL HIGH IS ALSO FORCING A TIGHT PRES GRADIENT ALONG THE W COAST OF BAJA CALIFORNIA WHERE SCATTEROMETER DATA ALSO SHOWED A FRESH TO STRONG N-NW BREEZE WITHIN 150 NM OF THE COAST N OF 25N. SEAS ACROSS THESE COASTAL WATERS OF BAJA WERE RUNNING 8- 10FT IN FRESH NW SWELL. THE FRONT ASSOCIATED WITH THE STRONGSTORM SYSTEM N OF HAWAII WILL SQUEEZE THE SUBTROPICAL HIGH WELL NORTHWARD MON...CAUSING TRADEWINDS AND WINDS OFF THE W COAST OF BAJA CALIFORNIA TO DIMINISH BELOW 20 KT OR LESS...WHILE NW SWELL BRIEFLY SUBSIDES. GAP WINDS... GULF OF CALIFORNIA...N-NW WINDS HAVE REMAINS AT A FRESH TO STRONG BREEZE ACROSS THE GULF OF CALIFORNIA FROM 23N-28N TONIGHT AS HIGH PRES BUILDS OVER THE GREAT BASIN AND PRESSURES FALL OVER CENTRAL MEXICO. THE TIGHTEST PRES GRADIENT WILL GRADUALLY SHIFT NORTHWARD IN THE GULF BY THIS EVENING...WITH WINDS DIMINISHING TO 15-20 KT THIS AFTERNOON THROUGH TUESDAY MORNING...BEFORE STRENGTHENING AGAIN TO 20-25 KT ACROSS CENTRAL PORTIONS LATE TUE AFTERNOON THROUGH THU. SEAS ACROSS CENTRAL AND S CENTRAL PORTIONS WILL BUILD 6-9 FT DURING THIS TIME. GULF OF TEHUANTEPEC...THE PRES GRADIENT BETWEEN HIGH PRES TO THE NORTH AND RELATIVE LOW PRES FARTHER SOUTH IN THE DEEP TROPICS HAS WEAKENED ACROSS THE ISTHMUS OF TEHUANTEPEC. WINDS HAVE FALLEN TO A MAX OF 20 KT ACROSS THIS AREA...WITH SEAS 3-5 FT. HOWEVER...A STRONG COLD FRONT WILL MOVE ACROSS THE GULF OF MEXICO TUE NIGHT AND WEDNESDAY...AND WILL RESULT IN ANOTHER GALE FORCE WIND EVENT ACROSS THE TEHUANTEPEC REGION WED EVENING THROUGH FRI MORNING. STRONG GALES ARE EXPECTED WED NIGHT AND ARE EXPECTED TO REACH AROUND 45 KT...WITH THE POTENTIAL TO REACH STORM FORCE. 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. A FRESH TO STRONG NE BREEZE IS CURRENTLY IN PLACE DOWNWIND OF PAPAGAYO TO 10N89W. NOCTURNAL DRAINAGE FLOW HAS INCREASED WINDS LATE TONIGHT TO AROUND 30 KT...BUT WILL DIMINISH TO AROUND 20 KT THIS AFTERNOON 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-10N BETWEEN 95W-105W. THESE CONDITIONS WILL GRADUALLY SHRINK WESTWARD AND SUBSIDE BELOW 8 FT BY THIS EVENING. GULF OF PANAMA...WEAKENING RIDGING N OF THE AREA HAS WEAKENED THE PRES GRADIENT ACROSS THE GULF OF PANAMA TONIGHT. FRESH TO STRONG N-NE WINDS WITH SEAS 6 TO 8 FT ARE EXPECTED TO PERSIST GENERALLY FROM 05N-08N BETWEEN 79W-81W THROUGH SUNRISE THIS MORNING BEFORE DIMINISHING AS THE HIGH PRES OVER THE NW CARIBBEAN WEAKENS. $$ STRIPLING