000 AXPZ20 KNHC 180331 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0100 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 PRES GRADIENT WILL INCREASE TONIGHT AS THE HIGH PRES N OF THE AREA BUILDS. WINDS WILL INCREASE IN RESPONSE AND ARE EXPECTED TO BE JUST SHY OF STORM FORCE THU MORNING DURING THE PERIOD OF PEAK NOCTURNAL DRAINAGE FLOW. SEAS WILL BUILD AS HIGH AS 15-17 FT. WINDS SHOULD REMAIN AROUND 40 KT MIDDAY THU THROUGH FRI MORNING AND DIMINISH AGAIN TO A MINIMAL GALE BY MIDDAY FRI AS THE RIDGE AXIS IN THE GULF OF MEXICO SHIFTS NORTHWARD. THE NE SWELL FROM THE GULF OF TEHUANTEPEC AND THE GULF OF PAPAGAYO WILL GENERATE COMBINED SEAS OVER 8 FT ACROSS A LARGE SWATH OF THE PACIFIC GENERALLY FROM 03N- 13N BETWEEN 91W AND 121W BY THE END OF THE FORECAST PERIOD FRI EVENING. GULF OF PAPAGAYO GALE WARNING...WINDS AND SEAS ARE BELIEVED TO HAVE TEMPORARILY DIMINISHED IN THE GULF OF PAPAGAYO BELOW THE ADVISORY CRITERIA. HIGH PRES WILL BUILD MARKEDLY N OF THE AREA BY EARLY THU MORNING. THE TIGHTENED PRES GRADIENT SHOULD INCREASE WINDS TO NEAR GALE FORCE DURING THE NOCTURNAL MAXIMUM OF DRAINAGE FLOW WHILE THE AREAL EXTENT OF THE FRESH TO STRONG NE WINDS SPREADS WELL DOWNWIND OF PAPAGAYO TO NEAR 07N97W THU. SEAS WILL BUILD AS HIGH AS 8-10 FT. WINDS AND SEAS SHOULD REMAIN ABOVE ADVISORY CRITERIA THU AFTERNOON AND EVENING AND WILL INCREASE OVERNIGHT. WINDS ARE NOW FORECAST TO REACH GALE FORCE DURING THE PERIOD OF NOCTURNAL DRAINAGE FLOW FRI MORNING... DIMINISH BELOW GALE FORCE AFTER SUNRISE FRI AND TO A FRESH TO STRONG BREEZE BY FRI EVENING. ...INTERTROPICAL CONVERGENCE ZONE... THE ITCZ AXIS WAS ANALYZED FROM 03N88W TO 04N96W TO 02N104W TO 05N120W...THEN RESUMES FROM 04N126W TO 01N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 240 NM EITHER SIDE OF THE AXIS BETWEEN 107W-120W. A TROUGH WAS ANALYZED FROM 11N123W TO 03N125W. SCATTERED MODERATE CONVECTION WAS ON THE NE SIDE OF THE TROUGH FROM 09N-15N BETWEEN 117W-124W. ...DISCUSSION... A COLD FRONT STRETCHES ACROSS NW WATERS FROM 32N126W TO 30N127W TO 24N140W. A FRESH TO STRONG NW BREEZE BEHIND THE FRONT WAS OBSERVED BY THE 1924 UTC ASCAT PASS W OF THE FRONT N OF 28N. THESE FRESH TO STRONG NW WINDS WILL DIMINISH OVERNIGHT WHEN THE FRONT BEGINS TO WEAKEN. THE SWELL WILL CONTINUE TO PROPAGATE SOUTHEASTWARD...WITH SEAS OVER THE FORECAST AREA EXPECTED TO PEAK AROUND 12-16 FT ON THU N OF 28N BETWEEN 125W-135W BEFORE SUBSIDING TO A MAXIMUM OF 11 FT NEAR 25N125W FRI EVENING. HIGH PRES OVER THE NORTHERN WATERS HAS WEAKENED IN ADVANCE OF THE AFOREMENTIONED COLD FRONT. THE MOST RECENT ASCAT PASSES SHOW TRADE WINDS HAVE DIMINISHED BELOW A FRESH TO STRONG BREEZE. HIGH PRES WILL BE SLOW TO BUILD IN BEHIND THE COLD FRONT AS A SECOND FRONT IS EXPECTED FAST ON ITS HEELS. THIS FRONT WILL CLIP NW WATERS FRI WITH LITTLE FANFARE. GAP WINDS... GULF OF PANAMA...THE INCREASE IN RIDGING N OF THE AREA MENTIONED WITH THE GALE WARNINGS ABOVE SHOULD DRIVE A STRONGER PRES GRADIENT ACROSS THE GULF OF PANAMA AS WELL. FRESH TO STRONG N WINDS ARE EXPECTED S OF THE GULF OF PANAMA TO 05N BEGINNING EARLY THU MORNING. THESE FRESH TO STRONG WINDS ARE EXPECTED TO DIMINISH BY THU AFTERNOON ONLY TO RETURN THU EVENING THROUGH FRI EVENING WHEN THEY SHOULD REACH AS FAR S-SW AS 02N85W WITH SEAS BUILDING AS HIGH AS 10 FT. $$ SCHAUER