000 AXPZ20 KNHC 180959 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU FEB 18 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... GULF OF TEHUANTEPEC GALE WARNING...A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRES N OF THE AREA AND RELATIVELY LOW PRES FARTHER SOUTH IN THE DEEP TROPICS IS SUPPORTING PERSISTENT GALE FORCE WINDS IN THE GULF OF TEHUANTEPEC. THE ADDITION AND ASSISTANCE OF NOCTURNAL DRAINAGE FLOW IS ALLOWING FOR WINDS TO INCREASE UP TO 45 KT THROUGH THE REMAINDER OF THE OVERNIGHT HOURS. SEAS WILL BUILD AS HIGH AS 15-17 FT BY SUNRISE. WINDS WILL THEN DIMINISH BACK TO 30-40 KT BY THE AFTERNOON WHICH WILL PERSIST THROUGH FRI AFTERNOON BEFORE DIMINISHING SLIGHTLY TO 30-35 KT. MINIMAL GALE FORCE WINDS WILL FINALLY GIVE UP SUN MORNING. GULF OF PAPAGAYO GALE WARNING...HIGH PRES IS BUILDING DOWN ACROSS INTERIOR CENTRAL AMERICA TIGHTENING THE PRES GRADIENT WITH LOWER PRES LOCATED JUST TO THE S-SW. THIS GRADIENT PATTERN COMBINED WITH COMMENSURATE NOCTURNAL DRAINAGE FLOW IS ALLOWING FOR GAP WIND FLOW TO INCREASE TO 20-30 KT WITH SEAS EXPECTED TO BUILD TO UP TO 10 FT BY SUNRISE THIS MORNING. THE GRADIENT WILL TIGHTEN EVEN MORE LATE TONIGHT THROUGH EARLY FRI WITH WINDS INCREASING TO MINIMAL GALE FORCE IN THE IMMEDIATE GULF OF PAPAGAYO AREA. WINDS WILL BRIEFLY DROP BELOW GALE FORCE FRI AFTERNOON...WITH ANOTHER SURGE TO MINIMAL GALE FORCE EXPECTED LATE FRI NIGHT INTO EARLY SAT...AND YET AGAIN POSSIBLE LATE SAT NIGHT INTO EARLY SUN. ...INTERTROPICAL CONVERGENCE ZONE... THE ITCZ AXIS EXTENDS FROM 03N94W TO 02N110W TO 04N122W THEN RESUMES FROM 04N126W TO 01N140W. SCATTERED MODERATE CONVECTION IS FROM 02N TO 07N BETWEEN 112W AND 120W...AND ALSO WITHIN 150 NM EITHER SIDE OF A LINE FROM 16N115W TO 10N122W. ...DISCUSSION... N OF 15N E OF 120W...WEAKENING 1015 MB HIGH PRES NEAR 25N118W EXTENDS A RIDGE SE TO NEAR THE REVILLAGIGEDO ISLANDS AHEAD OF A COLD FRONT WHICH IS APPROACHING FROM 30N125W TO 22N140W. LIGHT AND VARIABLE WINDS CURRENTLY DOMINATE THE WATERS UNDER THIS HIGH. THE FRONT WILL REACH FROM 30N119W TO 24N126W TO 19N140W BY LATE TONIGHT THEN WILL DISSIPATE AS IT MOVES ACROSS NW MEXICO EARLY THIS WEEKEND. WINDS WILL BECOME NW AND INCREASE TO MODERATE BEHIND THE FRONT THIS WEEKEND AS NEW HIGH PRES BUILDS IN...LOCALLY UP TO 20 KT OFFSHORE OF THE BAJA CALIFORNIA PENINSULA. ASSOCIATED NW SWELLS OF 8 FT OR GREATER WILL ALSO REACH THE BAJA CALIFORNIA COAST FRI MORNING...UP TO 11 FT NEAR 30N116W LATE FRI NIGHT. THE EDGE OF SEAS OF 8 FT OR GREATER WILL REACH OFFSHORE OF CABO SAN LUCAS SAT EVENING THEN WILL GRADUALLY DECAY THEREAFTER. GULF OF CALIFORNIA...MAINLY LIGHT SOUTHERLY WINDS PREVAIL EXCEPT IN THE NORTHERN GULF WHERE MODERATE TO FRESH SOUTHERLY WINDS ARE PULSING TO THE E OF SURFACE TROUGHING EXTENDING ALONG 114W. WINDS WILL BECOME NORTHERLY ACROSS THE ENTIRE GULF BY SAT MORNING BEHIND A DECAYING COLD FRONT...AND WILL INCREASE TO MODERATE TO FRESH BY SUN MORNING. THE PRES GRADIENT WILL TIGHTEN ACROSS THE GULF FOR THE END OF THE WEEKEND INTO EARLY NEXT WEEK WITH NW FLOW INCREASING TO 20-25 KT S OF 29N BY SUN EVENING THROUGH MON AFTERNOON. S OF 15N E OF 110W...FRESH TO STRONG N-NE FLOW HAS RETURNED IN THE GULF OF PANAMA IN THE PAST FEW HOURS. THE COVERAGE OF THESE WINDS WILL EXPAND WITH PEAK WINDS INCREASING TO 30 KT BY FRI AFTERNOON INTO THE WEEKEND AS THE PRES GRADIENT TIGHTENS ACROSS THE AREA. FRESH N-NE SWELLS GENERATED BY THESE WINDS WILL PROPAGATE WELL AWAY FROM THE SOURCE REGION TO NEAR 01N85W BY LATE FRI NIGHT. ELSEWHERE...MODERATE TO LOCALLY FRESH TRADES PREVAIL S OF RIDGING. OLD LONG PERIOD NW SWELL SPREADING ALL THE WAY TO THE EQUATOR NEAR 104W WILL CONTINUE TO DECAY THROUGH THE REMAINDER OF THE WEEK. A NEW ROUND OF NW SWELL IN EXCESS OF 8 FT IS ARRIVING BEHIND A COLD FRONT MENTIONED ABOVE. THIS NEW SET OF NW SWELL WILL ENVELOP THE NW AND W CENTRAL WATERS THIS WEEKEND. MEANWHILE FRESH NE SWELLS GENERATED BY GAP WIND FLOW IN THE GULFS OF TEHUANTEPEC AND PAPAGAYO WILL PROPAGATE WELL TO THE SW- W AWAY FROM THE SOURCE REGIONS...EVENTUALLY MIXING AND COMBINING WITH THE LONGER PERIOD NW SWELLS NEAR 120W BY SAT MORNING. $$ LEWITSKY