000 AXPZ20 KNHC 111513 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED MAR 11 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1530 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...1020 MB HIGH PRES IS CENTERED ALONG THE COAST OF MEXICO JUST N OF TAMPICO. THIS IS BUILDING BEHIND A COLD FRONT MAKING SLOW PROGRESS ACROSS THE WESTERN GULF...ALLOWING NORTHERLY WINDS TO FUNNEL ALONG THE MEXICAN COAST...EVENTUALLY MOVING ACROSS THE TEHUANTEPEC ISTHMUS INTO THE GULF OF TEHUANTEPEC BY LATE TODAY. THESE WINDS ARE EXPECTED TO REACH MINIMAL GALE FORCE OVERNIGHT AND REMAINING TO AT LEAST NEAR GALE FORCE THROUGH EARLY FRI. THE WINDS WILL INDUCE SEAS UP TO 12 OR 13 FT IN THE GULF BEFORE SUBSIDING TO AROUND 10 FT LATE THU...AND TO 8 FT FRI AS THE WINDS DIMINISH TO 20 KT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE ITCZ AXIS EXTENDS FROM 06N85W TO 04N115W TO 05N125W TO 04N140W. SCATTERED MODERATE CONVECTION PERSISTS WITHIN 30 NM EITHER SIDE OF AXIS BETWEEN 85W AND 95W. ...DISCUSSION... E OF 120W... A SHARP UPPER TROUGH CONTINUES TO EXTEND FROM THE SOUTHERN PLAINS ACROSS NW MEXICO AND SOUTHWARD INTO THE EASTERN PACIFIC BETWEEN 100W AND 105W. RELATIVELY DRY AND STABLE AIR ON THE WEST SIDE OF THE TROUGH IS SUPPRESSING ANY MAJOR CONVECTION ALONG THE ITCZ W OF 95W. WEAK CONFLUENCE IS SUPPORTING A FEW SHOWERS ALONG THE ITCZ BETWEEN 85W AND 95W. IN ADDITION TO THE GULF OF TEHUANTEPEC...GAP WINDS PERSIST FARTHER SOUTH IN THE VICINITY OF THE GULF OF PAPAGAYO AS NOTED IN EARLIER ASCAT SATELLITE DATA. THIS PRIMARILY DUE TO STRONG AND PERSISTENT TRADE WIND FLOW ACROSS THE CARIBBEAN...CROSSING NORTHERN COSTA RICA AND SOUTHERN NICARAGUA. THESE PULSES ARE EXPECTED TO PERSIST THROUGH EARLY FRI PRIMARILY OVERNIGHT...GENERATING AREAS OF SHORT PERIOD SWELL DOWNSTREAM WITH SEAS REACHING 9 FT IN THE AFTERNOONS BEFORE DECAYING QUICKLY BELOW 8 FT. W OF 120W... A SHORT WAVE TROUGH EMBEDDED IN THE SOUTHERN JET IS PASSING TO THE NE NEAR 30N130W. A 1018 MB HIGH PRES CENTERED NEAR 28N127W IS SHIFTING NE ACCORDINGLY...ALLOWING ONLY TRADE WIND FLOW ACROSS THE DEEP TROPICS AS NOTED IN VARIOUS ASCAT SATELLITE PASSES AND TOGA-TAO BUOY OBSERVATIONS. A FRONTAL BOUNDARY REMAINS STALLED EAST OF THE HIGH FROM 30N134W TO 25N140W. THIS WILL DISSIPATE THROUGH TONIGHT AS THE UPPER SUPPORT LIFTS OUT. THE PATTERN THROUGH THE REMAINDER OF THE WEEK WILL BE DOMINATED BY A SHARP UPPER TROUGH AMPLIFYING FROM THE NE PACIFIC THOUGH HAWAII...SUPPORTING THE APPROACH OF A COLD FRONT TOWARD THE NW CORNER OF THE DISCUSSION AREA BY LATE FRI. THE GFS CONTINUES TO INDICATE STRONG SOUTHERLY FLOW IN THE FAR NW CORNER AHEAD OF LOW PRES FORMING ALONG THE FRONT...BUT OTHER MODELS ARE STARTING TO BACK OFF ON THIS IDEA AND THIS HAS BEEN TONED DOWN IN THE OFFICIAL FORECAST. WAVE MODELS ARE STILL IN GOOD AGREEMENT INDICATING LONG PERIOD NW SWELL WITH HEIGHTS TO AT LEAST 9 FT ENTERING THE AREA FRI AHEAD OF THE FRONT. FARTHER SOUTH...ALTHOUGH TRADE WIND FLOW IS RELATIVELY MINIMAL...MIXED NW AND SE SWELL CONTINUES TO PROMOTE COMBINED SEAS AROUND 8 FT S OF 14N W OF 130W AS NOTED IN RECENT ALTIMETER SATELLITE PASSES. THIS SWELL WILL SUBSIDE BELOW 8 FT THROUGH 48 HOURS. $$ CHRISTENSEN