000 AXPZ20 KNHC 301536 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC TUE DEC 30 2014 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 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF COLOMBIA NEAR 07N78W TO NEAR 05N90W...WHERE IT TRANSITIONS TO THE ITCZ. THE ITCZ CONTINUES FROM 05N90W TO 06N125W TO WEST OF 07N140W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 90 NM S OF THE MONSOON TROUGH AXIS E OF 80W...WITHIN 90 NM OF THE ITCZ BETWEEN 90W AND 95W. ...DISCUSSION... A NEGATIVELY TILTED MID TO UPPER LEVEL TROUGH PERSISTS FROM THE N CENTRAL PACIFIC N OF HAWAII SOUTHEASTWARD TOWARD A CLOSED UPPER LOW NEAR 26N135W. AN ASSOCIATED 1012 MB SURFACE LOW IS CENTERED NEAR 26N137W...WITH A WEAK COLD FRONT TRAILING TOWARD 20N135W THEN TO 16N140W. A 0530 UTC ASCAT SCATTEROMETER PASS INDICATED FRESH TO STRONG SE FLOW WITHIN APPROXIMATELY 400 NM E OF THE COLD FRONT...BETWEEN THE LOW PRES CENTER AND AN ELONGATED SURFACE RIDGE AXIS PARALLELING THE U.S. WEST COAST AND THE COAST OF BAJA CALIFORNIA. INSTABILITY ASSOCIATED WITH THE UPPER TROUGH IS SUSTAINING AREAS OF SHOWERS AND THUNDERSTORMS WITHIN 180 NM E OF THE FRONT. THE UPPER TROUGH WILL WEAKEN AS IT SHIFTS EASTWARD OVER THE NEXT COUPLE OF DAYS TOWARD THE BAJA CALIFORNIA PENINSULA...EVENTUALLY COMING INTO PHASE WITH ANOTHER MID/UPPER IMPULSE MOVING SOUTHWARD DOWN THE WESTERN UNITED STATES. THE LOW PRES WILL OPEN INTO A TROUGH AND THE FRONT WILL BECOME DIFFUSE THROUGH EARLY WED...WITH WINDS AHEAD OF THE FRONT DIMINISHING AS WELL. GULF OF CALIFORNIA...A COLD FRONT ASSOCIATED WITH THE MID/UPPER TROUGH MOVING SOUTHWARD ACROSS THE WESTERN UNITED STATES WILL MOVE INTO BAJA CALIFORNIA NORTE AND THE NORTHERN GULF OF CALIFORNIA WED...THEN BECOME DIFFUSE AS IT SHIFTS SOUTHWARD DOWN THE PENINSULA. THERE MAY BE A BRIEF PERIOD OF FRESH TO STRONG SW WINDS OVER THE NORTHERN GULF OF CALIFORNIA TONIGHT...CONNECTED TO WEAK AND TRANSIENT LOW PRES FORMING ALONG THE FRONT OVER THE LOWER COLORADO RIVER DELTA. THERE IS BROAD AGREEMENT AMONG GLOBAL MODELS HINTING AT THIS...BUT FETCH AND DURATION WILL BE TOO LIMITED TO SUPPORT ANY SIGNIFICANT WAVE GROWTH. LOOKING AHEAD...HIGH PRES BUILDING OVER THE GREAT BASIN WILL SUPPORT DEVELOPMENT OF FRESH NW FLOW DOWN THE LENGTH OF THE GULF OF CALIFORNIA BY LATE THU. SHORTER PERIOD NORTHERLY SWELL GENERATED BY STRONG NORTHERLY WINDS OFF THE COAST OF CALIFORNIA WITH COMBINED SEAS TO 8 FT WILL PROPAGATE SOUTH OF 30N WED...IMPACTING THE AREA N OF 29N BETWEEN 115W AND 125W BEFORE SUBSIDING BELOW 8 FT BY EARLY THU. FARTHER SOUTH...THE PRESENCE OF THE LOW PRES INTO THE SUBTROPICAL RIDGE IS LIMITING TRADE WIND DEVELOPMENT BETWEEN THE ITCZ AND 20N. GENERALLY MODERATE TO OCCASIONALLY FRESH TRADES CAN BE EXPECTED THROUGH THE REMAINDER OF THE WEEK. A FEW SHOWERS WERE NOTED ALONG THE ITCZ BETWEEN 125W AND 130W AHEAD OF THE TRAILING END OF THE MID/UPPER TROUGH TO THE NORTH. GAP WINDS...STRONG HIGH PRES OVER THE NORTHERN PLAINS WILL MOVE SOUTHWARD ALONG THE FRONT RANGE OF THE ROCKIES INTO THE SOUTHERN PLAINS THROUGH LATE WED. ALTHOUGH WELL REMOVED FROM THE EASTERN PACIFIC...THE STRENGTH OF THE HIGH PRES WILL INITIATE CONDITIONS FAVORABLE FOR STRONG GAP WINDS THROUGH THE GULFS OF TEHUANTEPEC AND PAPAGAYO STARTING TONIGHT. FOR THE GULF OF TEHUANTEPEC...WINDS WILL REACH AT LEAST 30 KT TONIGHT WITH SEAS BUILDING AS HIGH AS 11 FT BY EARLY WED. THE HIGH PRES SHIFTS FARTHER SOUTH THROUGH LATE WED...ALLOWING GAP WINDS TO GALE FORCE THROUGH EARLY THU. WINDS AND SEAS DIMINISH THROUGH THU AS THE HIGH PRES WEAKENS AND SHIFTS EAST. GULF OF PAPAGAYO...GAP WINDS WILL PULSE TO 30 KT OVER THE NEXT COUPLE OF NIGHTS WITH SEAS BUILDING AS HIGH AS 9 OR 10 FT...WITH FURTHER EVENTS TO 25 KT INTO THE WEEKEND. $$ CHRISTENSEN