000 AXPZ20 KNHC 240352 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON DEC 24 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 0330 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 06N77W TO 04N82W TO 06N89W...WHERE IT TRANSITIONS TO THE ITCZ AND CONTINUES THROUGH 06N105W TO 08N115W TO 07N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 90 NM OF 03N81W...AND WITHIN 90 NM OF THE ITCZ BETWEEN 104W AND 110W. ...DISCUSSION... LARGE MID-TO UPPER LEVEL ANTICYCLONE CENTERED NEAR THE COAST OF MEXICO AT 15N100W DOMINATES THE FLOW OVER THE EAST PACIFIC E OF 125W. AN UPPER LEVEL TROUGH/SHEAR AXIS EXTENDS FROM THE FAR NW CORNER OF BAJA CALIFORNIA WSW THROUGH 27N127W 22N135W THROUGH 17N140W. STRONG WSW FLOW BETWEEN THE TWO FEATURES WITHIN THE AXIS OF A VERY STRONG SUBTROPICAL JETSTREAM WAS TRANSPORTING COPIOUS AMOUNTS OF MID TO UPPER LEVEL MOISTURE NE ACROSS BAJA CALIFORNIA...NORTHERN OLD MEXICO INTO THE SOUTHERN GREAT PLAINS OF THE U.S. AND WAS FUELING MID-LATITUDE CYCLOGENESIS OVER THE CONUS. THE CORE OF THE JETSTREAM WITH SATELLITE DERIVED WINDS IN EXCESS OF 150 KT EXTENDED FROM THE BASE OF THE AFOREMENTIONED TROUGH NEAR 16N135W THROUGH 23N130W 30N115W ACROSS NORTH-CENTRAL TEXAS. AT THE SURFACE...SUBTROPICAL RIDGE FROM 31N120W TO 26N140W REMAINS THE PRIMARY SYNOPTIC FEATURE IN THE REGION. 1710 AND 1850 UTC ASCAT PASSES SHOWED A LARGE AREA OF FRESH 20-25 KT NE TRADE WINDS S OF THE RIDGE...WITH HIGHEST WINDS AND SEAS FROM 07N TO 21N W OF 127W. LARGE LONG PERIOD NW SWELL UP TO 20-21 SECONDS CONTINUES TO SWEEP SOUTHWARD OVER THE DISCUSSION AREA AND NOW EXTENDING INTO THE SOUTHERN HEMISPHERE...WITH COMBINED SEAS TO 15 FT W OF 110W....ABOUT 2-3 FT ABOVE THE WAVE WATCH GUIDANCE PER AN 1900 UTC JASON ALTIMETER PASS. EAST OF 110W MERGING NE SWELL GENERATED BY HIGH WINDS NEAR THE GULFS OF PAPAGAYO AND TEHUANTEPEC...AS WELL AS FONSECA TO LESSER EXTENT...ARE CREATING A LARGE AREA OF 8-12 FT SEAS S OF 14N. SUBTROPICAL RIDGE WILL REMAIN ANCHORED ALONG 27N THROUGH TUE NIGHT WHILE A WEAKENING COLD FRONT MOVES EASTWARD N OF 30N. THE TRAILING EDGE OF THE FRONT WILL AFFECT THE FAR NE PORTION OF THE AREA WED INTO WED NIGHT. STRONGER WINDS N OF THE AREA WILL RESULT IN 10-11 FT SEAS PUSHING INTO PORTIONS N OF 25N BY THU. STRONG HIGH PRES THAT DEVELOPS BEHIND THE FRONT NEAR 35N140W WED SHIFTS SLOWLY SOUTHEAST THROUGH FRI AS ANOTHER CENTRAL PACIFIC COLD FRONT PUSHES EASTWARD N OF 30N. THE ITCZ WILL REMAIN SITUATED ALONG 8N/9N THROUGH FRI...SUPPORTING MODERATE TO FRESH NE TRADE WINDS S OF THE SUBTROPICAL RIDGE FROM 09N TO 20N W OF 110W THROUGH WED THEN SHIFT FURTHER WEST WED NIGHT THROUGH FRI AS THE RIDGE WEAKENS. GAP WINDS... AN 1856 UTC OCEAN SAT SCATTEROMETER PASS INDICATED 25-30 KT WINDS IN THE GULF OF TEHUANTEPEC...CONFIRMING THAT THE GAP WINDS DID DROP BELOW GALE FORCE WITH THE 1800 UTC HIGH SEAS ISSUANCE. SINCE THEN OBSERVATIONAL DATA FROM IXTEPEC MEXICO INDICATED SURFACE WINDS HAVE DECREASED TO 15 KT AT THAT LOCATION POSSIBLY SIGNALING THAT THE GAP WINDS IN THE TEHUANTEPEC MAY BE DECREASING FURTHER. WITH SOUTHERLY RETURN FLOW INCREASING IN THE GULF OF MEXICO THE GAP WIND EVENT SHOULD END ALTOGETHER AFTER SUNRISE MON. FURTHER SOUTH...A 1718 UTC OSCAT PASS INDICATED 25-30 KT WINDS IN THE GULF OF PAPAGAYO AND A SEPARATE AREA OF WINDS IN THE GULF OF FONSECA AS WELL. THESE WINDS ARE EXPECTED TO GRADUALLY DECREASE OVER THE NEXT 24 TO 36 HOURS. $$ COBB