000 AXPZ20 KNHC 260350 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE MAR 26 2013 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 0315 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS PRESENTLY NOT IDENTIFIABLE. ITCZ AXIS EXTENDS FROM 06N84W TO 03N94W THEN RESUMES AT 01N118W TO BEYOND 04N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED S OF 02N BETWEEN 118W AND 122W. SCATTERED MODERATE CONVECTION IS FROM 02N TO 04N BETWEEN 125W AND 127W. ...DISCUSSION... GAP WINDS...A VERY TIGHT PRES GRADIENT ACROSS THE ISTHMUS OF TEHUANTEPEC ASSOCIATED WITH STRONG HIGH PRES BUILDING OVER THE FAR WESTERN GULF OF MEXICO IS INDUCING STRONG NLY FLOW THROUGH THE CHIVELA PASS...AND INTO THE GULF OF TEHUANTEPEC AS NOTED BY LATEST SCATTEROMETER DATA. THE 1854 UTC OSCAT PASS PROVIDED OBSERVATIONS OF 20-30 KT ACROSS THE GULF. AN ARC CLOUD WAS EARLIER NOTED ON VISIBLE SATELLITE IMAGERY PROPAGATING S AND SW AWAY FROM THE GULF INDICATING THE LEADING EDGE OF THE CURRENT GAP WIND EVENT. IN ADDITION...SALINAS CRUZ IN THE STATE OF OAXACA MEXICO WAS REPORTING SUSTAINED WINDS OF 25 KT. A SHIP OBSERVATION WITH CALL SIGN "A8NQ6" REPORTED WINDS TO NEAR GALE FORCE JUST S OF THE GULF NEAR 15N95W JUST A FEW HOURS AGO. WINDS ARE FORECAST TO REACH 40 KT NEAR DAYBREAK TODAY AS COLD DENSE AIR RELATED TO THE STRONG HIGH PRES SURGES S THROUGH ISTHMUS OF TEHUANTEPEC AND ACROSS THE GULF. THE SEAS IN THE GULF OF TEHUANTEPEC ARE FORECAST TO BUILD TO 14-15 FT EARLY THIS MORNING...AND TO 16-17 FT OVERNIGHT TONIGHT AND INTO EARLY WED MORNING WHEN THE STRONGEST WINDS ARE EXPECTED. THE PRES GRADIENT IS FORECAST TO BEGIN TO SLACKEN LATE WED INTO THU ALLOWING FOR THE GALE CONDITIONS TO DIMINISH LATE THU MORNING. INCREASING TRADE WINDS OVER THE CARIBBEAN REGION ARE FORECAST TO EXTEND INTO THE GULF OF PAPAGAYO EARLY WED MORNING...WHEN SURFACE WINDS ARE EXPECTED TO REACH 20-25 KT WITH BUILDING SEAS TO AROUND 8 FT. THIS WEATHER PATTERN WILL PERSIST ON THU WITH SEAS RANGING FROM 8 TO 10 FT. WINDS WILL BE GREATEST DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW. SEAS GENERATED IN BOTH GAP WIND AREAS...TEHUANTEPEC AND PAPAGAYO ARE FORECAST TO MERGE LATE WED WITH 8-11 FT SEAS COVERING THE WATERS FROM 07N TO 13N BETWEEN 89W AND 105W. A WEAKENING COLD FRONT IS NEAR 30N140W. IT IS FORECAST BY THE COMPUTER MODELS TO SLOWLY MOVE SE ACROSS THE NW WATERS THROUGH THU. BESIDES THE WIND SHIFT ASSOCIATED WITH THE FRONT...NO SIGNIFICANT IMPACT ON WINDS AND SEAS IS EXPECTED FROM IT. A REINFORCING COLD FRONT WILL THEN REACH THE FAR NW CORNER OF THE AREA BY THU MERGING WITH THE MAIN FRONT. THE MERGED FRONT WILL EXTEND FROM 31N131W TO 23N140W THU EVENING FOLLOWED BY FRESH TO STRONG WINDS AND BUILDING SEAS TO AROUND 9 FT. A 1019 MB HIGH PRES LOCATED NEAR 29N135W EXTENDS A RIDGE SE TO NEAR 20N110W. MAINLY LIGHT WINDS ARE NOTED PER THE 2028 UTC OSCAT PASS N OF 20N UNDER THE INFLUENCE OF THIS SYSTEM. WINDS INCREASE TO 15-20 KT ON THE SOUTHERN PERIPHERY OF THE RIDGE AND N OF THE ITCZ AXIS. THIS WEAK HIGH PRES WILL MOVE NE AND REMAIN OVER THE N WATERS THROUGH THE NEXT 48 HRS ALLOWING FOR RATHER LIGHT WINDS THROUGHOUT. AN AREA OF 8 FT SEAS IN MIXED NE AND NW SWELL IN NOTED WITHIN THE TRADE WINDS FROM 07N TO 10N W OF 132W. THESE SWELLS ARE FORECAST BY WAVEWATCH MODEL GUIDANCES TO GRADUALLY SUBSIDE TO LESS THAN 8 FT BY 24 HRS. $$ GR