000 AXPZ20 KNHC 270320 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE NOV 27 2012 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 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 07N78W TO 07N94W. ITCZ AXIS EXTENDS FROM 07N94W TO 09N110W TO 10N129W TO 10N140W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE OF ITCZ AXIS BETWEEN 110W AND 128W. ...DISCUSSION... E OF 110W... GALE CONDITIONS WILL DEVELOP IN GULF OF TEHUANTEPEC THROUGH LATE WED. LAND BASED OBSERVATIONS AND A 00 UTC WINDSAT PASS INDICATE FAIRLY LIGHT WINDS PREVAIL CURRENTLY ACROSS THE GULF OF TEHUANTEPEC. THIS WILL CHANGE TUE AS A COLD FRONT IS EXPECTED TO PUSH INTO THE GULF OF MEXICO THROUGH TUE...FOLLOWED BY COOLER AND DRIER AIR RACING DOWN THE FAR WESTERN GULF OF MEXICO. THIS DENSER AIR WILL PLUNGE THROUGH THE CHIVELA PASS AND DELIVER WINDS TO GALE FORCE ACROSS THE GULF OF TEHUANTEPEC BY TUE EVENING. THE GALE CONDITIONS WILL PERSIST THROUGH EARLY THU AS THE AIRMASS OVER THE GULF OF MEXICO SLOWLY MODIFIES AND SHIFTS EAST. BY LATE WED...SEAS IN THE GULF OF TEHUANTEPEC WILL BUILD TO 15 FT...AND THE PLUME EMERGING OUT OF THE GULF OF TEHUANTEPEC WILL BRING WINDS IN EXCESS OF 20 KT AND SEAS OF 8 TO 10 FT UP TO 500 NM SE OF THE AREA TO AROUND 09N100W. FARTHER SOUTH IN THE GULF OF PAPAGAYO FRESH EASTERLY TRADEWINDS PERSIST. THESE WINDS WILL INCREASE TO 20 TO 25 KT BY LATE TUE NIGHT/EARLY WED MORNING AS HIGH PRES BUILDS N OF THE AREA AND TIGHTENS THE GRADIENT OVER THE SW CARIBBEAN. EXPECT THE DOWNSTREAM PLUME OF 20 TO 25 KT WINDS TO REACH UP TO 150 NM TO THE WSW OF THE GULF THROUGH 48 HOURS WITH SEAS TO 8 FT. A BROAD AREA OF RESIDUAL SWELL PERSISTS LEFTOVER FROM THE PREVIOUS TEHUANTEPEC GALE EVENT...EXTENDING FROM ROUGHLY 08N TO 11N BETWEEN 105W AND 113W IN MIXED NW AND E SWELL. GLOBAL WAVE MODELS ARE IN GOOD AGREEMENT SHOWING THIS SWELL SUBSIDING BELOW 8 FT IN THE NEXT 24 TO 36 HOURS. W OF 110W... A MID/UPPER LEVEL RIDGE IS CENTERED N OF 25N ALONG 120W. AN ASSOCIATED WEAK 1019 MB FRONT REMAINS STATIONARY FOR NOW NEAR 27N122W. TO THE WEST...A NEGATIVELY TILTED DEEP LAYER TROUGH CONTINUES TO DIG INTO THE NE PACIFIC...FROM A MID/UPPER CYCLONE NEAR 25N147W TO 30N140W. AN ASSOCIATED SURFACE COLD FRONT IS ANALYZED THROUGH 30N138W TO 25N140W THEN ON TO NEAR HAWAII. THE FRONT WILL PUSH ACROSS THE WATERS N OF 20N AND REACH FROM 30N127W TO 20N135W BY EARLY WED. A TIGHT GRADIENT SETS UP BETWEEN THE RESIDENT HIGH PRES AND THE INCOMING FRONT...ALLOWING WINDS TO INCREASE BOTH AHEAD AND BEHIND THE FRONT TONIGHT THROUGH WED. THE GFS REMAINS THE STRONGEST OF THE GLOBAL MODELS...WITH WINDS REACHING NEAR GALE FORCE TONIGHT AHEAD OF THE FRONT. A SHIP REPORT FROM 18 UTC NEAR 30N136W SUPPORTED THIS THEORY WITH 30 KT AND SEAS TO 9 FT. HOWEVER...A SCATTEROMETER PASS FROM OVERNIGHT SHOWED THE 30 KT WINDS TO BE WELL N OF 30N AHEAD OF THE FRONT. FORECAST MAINTAINS WINDS LESS THAN 30 KT S OF 30N THROUGH TONIGHT. BY WED...THE SUPPORTING UPPER TROUGH WILL LIFT NE...ALLOWING THE FRONT TO STALL AND WEAKEN HEADING INTO WED. HOWEVER...A SECOND MID/UPPER LEVEL SHORT WAVE TROUGH WILL ALLOW A REINFORCING PUSH WED INTO THU...DELIVERING A NEW ROUND OF W TO NW WINDS UP TO NEAR GALE FORCE BEHIND THE FRONT N OF 25N. IN ADDITION...WAVE MODELS CONTINUE TO SHOW LONG PERIOD NW SWELL ACCOMPANYING THIS FRONTAL SYSTEM. THE WW3 SHOWS SEAS BUILDING IN EXCESS OF 15 FT BEHIND THE FRONT GOING INTO WED...WITH THE FRONTAL EDGE OF SEAS 8 FT OR GREATER REACHING FROM 30N120W TO 15N140W BY EARLY THU. LOOKING AHEAD...GFS AND ECMWF INDICATE A SERIES OF SHORT WAVE TROUGHS CONTINUE TO FOLLOW IN LINE CUTTING INTO THE NW PORTION OF THE DISCUSSION AREA...THEN LIFTING NE...ALLOWING FRESH TO STRONG SW TO W SURFACE WINDS TO PULSE MAINLY N OF 25N W OF 130W. THE NW SWELL GREATER THAN 8 FT WILL REACH THE COAST OF NORTHERN BAJA BY LATE THU/EARLY FRI...AND COVER MOST OF THE AREA W OF 110W THROUGH SAT. $$ CHRISTENSEN