000 AXPZ20 KNHC 112106 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...1024 MB HIGH PRES IS CENTERED ABOUT 120 NM W OF MATAMOROS MEXICO. THIS HIGH IS BUILDING BEHIND A COLD FRONT MAKING SLOW PROGRESS ACROSS THE WESTERN GULF...ALLOWING NORTHERLY WINDS OF 20 TO 25 KT TO FUNNEL ALONG THE MEXICAN COAST AND ACROSS THE TEHUANTEPEC ISTHMUS INTO THE GULF OF TEHUANTEPEC. 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 LATE FRI AS THE WINDS DIMINISH TO 20 TO 25 KT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE ITCZ AXIS EXTENDS FROM 06N85W TO 04N95W TO 07N105W TO 05N120W TO 04N140W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 45-60 NM EITHER SIDE OF AXIS BETWEEN 87W AND 94W. ...DISCUSSION... E OF 120W... A MID TO UPPER LEVEL CYCLONE HAS CUT OFF OVER CENTRAL MEXICO NEAR 23N104W WITHIN THE SHARP TROUGH EXTENDING FROM THE SOUTHERN PLAINS ACROSS NW MEXICO AND SOUTHWARD INTO THE EASTERN PACIFIC BETWEEN 100W AND 110W. 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 87W AND 94W. IN ADDITION TO THE GULF OF TEHUANTEPEC...GAP WINDS HAVE DIMINISHED TO AROUND 20 KT IN THE VICINITY OF THE GULF OF PAPAGAYO AS NOTED IN A 1606 UTC ASCAT-B SCATTEROMETER PASS. THE WINDS ARE EXPECTED TO PULSE AGAIN OVERNIGHT TONIGHT. HOWEVER...UNLIKE THE PREVIOUS SEVERAL DAYS...THESE WINDS ARE FORECAST TO REMAIN AT 20 TO 25 KT THROUGH THE DAY THU AND POSSIBLY PULSE TO 30 KT OVERNIGHT THU INTO EARLY FRI. THE STEADIER WINDS ARE EXPECTED TO GENERATE WIND WAVES OF 9 FT AND AREAS OF SHORT PERIOD SWELL DOWNSTREAM. W OF 120W... A SHORT WAVE TROUGH EMBEDDED IN THE SOUTHERN JET IS PASSING TO THE N OF THE DISCUSSION AREA ALONG 127W. A 1022 MB HIGH PRES CENTERED NEAR 31N125W IS SHIFTING NE ACCORDINGLY...ALLOWING ONLY MODEST TRADE WIND FLOW ACROSS THE DEEP TROPICS AS NOTED IN VARIOUS ASCAT SATELLITE PASSES AND TOGA-TAO BUOY OBSERVATIONS. A DISSIPATING FRONTAL BOUNDARY FROM 30N133W TO 24N140W WAS NOTED WEST OF THE HIGH. THE FRONT WILL DISSIPATE 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 OF THE AREA AHEAD OF LOW PRES FORMING ALONG THE FRONT...HOWEVER OTHER GLOBAL MODELS ARE DOWNPLAYING THIS SCENARIO AND THIS SOLUTION IS REFLECTED 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. $$ COBB