000 AXPZ20 KNHC 120340 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU MAR 12 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 0315 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...1022 MB HIGH PRES IS CENTERED ABOUT 60 NM W OF MATAMOROS MEXICO. THIS HIGH IS BUILDING BEHIND A COLD FRONT MAKING SLOW PROGRESS ACROSS THE WESTERN GULF ALONG 92W. THIS IS ALLOWING NORTHERLY WINDS TO FUNNEL ALONG THE MEXICAN COAST AND ACROSS THE TEHUANTEPEC ISTHMUS INTO THE GULF OF TEHUANTEPEC. MOST RECENT SURFACE OBSERVATIONS FROM SALINA CRUZ INDICATED NORTHERLY WINDS OF 15 TO 25 KT SUGGESTING WINDS IN THE GULF OF TEHUANTEPEC HAVE NOW REACHED 30 KT. THESE WINDS ARE EXPECTED TO REACH MINIMAL GALE FORCE SHORTLY AND REMAIN AT LEAST NEAR GALE FORCE THROUGH FRI AFTERNOON. THE WINDS WILL BUILD 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 06N84W TO 04N95W TO 06N105W TO 04N120W TO 05N140W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 45 NM EITHER SIDE OF THE ITCZ BETWEEN 90W AND 93W...AND FROM 05N TO 07N BETWEEN 108W AND 110W. ...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. VERY DRY AND STABLE AIR WRAPPING AROUND THE WESTERN AND SOUTHERN SIDES OF THE TROUGH IS SUPPRESSING ANY MAJOR CONVECTION ALONG MOST OF THE ITCZ. WEAK LOW LEVEL CONFLUENCE IS SUPPORTING A FEW SHOWERS ALONG THE ITCZ BETWEEN 90W AND 93W...AND FROM 05N TO 07N BETWEEN 108W AND 110W. IN ADDITION TO THE GULF OF TEHUANTEPEC...GAP WINDS IN THE GULF OF PAPAGAYO ARE EXPECTED TO PULSE AGAIN OVERNIGHT TONIGHT. HOWEVER...UNLIKE THE PREVIOUS SEVERAL DAYS...THESE WINDS ARE FORECAST TO REMAIN AT 20 TO 25 KT THROUGHOUT THE DAY ON 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 OF THE GULF. LOOKING AHEAD...GLOBAL MODELS SUGGEST ANOTHER MID TO UPPER LEVEL CYCLONE WILL CUT-OFF OVER THE SOUTHERN GULF OF CALIFORNIA ON SAT AND MEANDER IN THE AREA THROUGH THE WEEKEND. DEEP LAYERED SOUTHERLY FLOW COUPLED WITH INCREASING PRECIPITABLE WATER VALUES OF 2 INCHES OR MORE COULD SET THE STAGE FOR POTENTIALLY HEAVY RAINFALL LATE IN THE WEEKEND ALONG THE COAST OF MEXICO FROM MANZANILLO TO PUERTO ANGEL. W OF 120W... A SHORT WAVE TROUGH EMBEDDED IN THE SUBTROPICAL JET IS SWEEPING TO THE N OF THE DISCUSSION AREA ALONG 123W. A 1022 MB HIGH PRES CENTERED NEAR 31N125W IS SHIFTING TO THE NORTHEAST...ALLOWING ONLY MODEST TRADE WIND FLOW ACROSS THE DEEP TROPICS AS NOTED IN SEVERAL RECENT ASCAT SATELLITE PASSES. A FRONTAL TROUGH FROM 30N133W TO 24N140W WAS NOTED WEST OF THE HIGH. 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. FOR SEVERAL CONSECUTIVE RUNS...THE GFS MODEL INDICATES 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. THE GRIDDED HIGH SEAS FORECAST REFLECTS THE SOLUTIONS OF THE OTHER GLOBAL MODELS AND KEEPS WINDS BELOW 20 TO 25 KT THRESHOLDS THROUGH 48 HOURS. WAVE MODELS REMAIN 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 BY 36 HOURS. $$ COBB