000 AXPZ20 KNHC 300351 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI NOV 30 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 0315 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 07N79W TO 09N85W TO 06N100W TO 06N106W WHERE LOW LEVEL WINDS SUGGEST IT TRANSITIONS TO THE ITCZ TO 05N120W TO 06N131W TO 07N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 120 NM N OF THE TROUGH E OF 91W AND BETWEEN 91W AND 103W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE TROUGH E OF 91W...AND ALSO BETWEEN 91W-103W. ...DISCUSSION... ALOFT... A LARGE DEEP LAYER CYCLONE WELL N OF REGION NEAR 46N139W EXTENDS A LONGWAVE TROUGH TO 32N136W AND SW TO W OF THE DISCUSSION AREA AT 17N140W. BROAD CYCLONIC FLOW IS EVIDENT N OF ABOUT 25N AND W OF 127W. THE TROUGH SUPPORTS A COLD FRONT FAST APPROACHING THE FAR NW SECTION OF THE AREA. THE FRONT EXTENDS ROUGHLY ALONG 32N W OF 137W AS CLEARLY IDENTIFIED BY A ROPE TYPE CLOUD FEATURE WITH POSSIBLE WIDELY SCATTERED SHOWERS. DIVERGENCE AHEAD OF A SHORTWAVE TROUGH NOTED IN THE SE PERIPHERY OF THE LONGWAVE TROUGH IS RESULTING IN OVERCAST MULTILAYERED CLOUDS WITH EMBEDDED SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE AREA FROM 19N TO 26N BETWEEN 116W AND A LINE FROM 30N121W TO 18N135W. DEBRIS MOISTURE FROM THIS ACTIVITY IS STREAMING EASTWARD TOWARDS TO CENTRAL AND SOUTHERN BAJA CALIFORNIA...AND TO INLAND CENTRAL MEXICO. OVER THE FAR EASTERN PORTION OF THE AREA...BROAD MID/UPPER LEVEL RIDGING DAMPENING WITH TIME AS IT TRANSLATES EWD IS PRESENT N OF 19N AND E OF THE TROUGH. AN ASSOCIATED ANTICYCLONE IS CENTERED AT 16N114W WITH A RIDGE WSW TO 18N140W. SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE S OF 18N E OF 126W...AND S OF 13N W OF 126W. OVER THE FAR SE PORTION...BROAD MID/UPPER RIDGING EXTENDS EWD TO OVER CENTRAL AMERICA AND THE NORTHERN PORTION OF S AMERICA. THE ANTICYCLONIC FLOW ASSOCIATED WITH IT IS TRANSPORTING DEBRIS CLOUDS FROM THE MONSOON TROUGH CONVECTION NWD TOWARDS TO SE MEXICO AND THE GULF OF TEHUANTEPEC. DRY AND STABLE ATMOSPHERIC CONDITIONS AS A RESULT OF THE SUBSIDENCE WITH THE MID/UPPER LEVEL RIDGING ARE PREVALENT THROUGHOUT THE SRN PORTION OF THE AREA WHERE ONLY SCATTERED LOW CLOUDS WITH ISOLATED SHOWERS MOVING WWD ARE NOTED. ELSEWHERE AT THE SURFACE... THE VERY LARGE CYCLONIC CIRCULATION TIED TO THE INTENSE LOW PRES SYSTEM THAT IS WELL N OF THE DISCUSSION AREA WITH ITS ASSOCIATED COLD FRONT APPROACHING THE FAR NW WATERS WILL BRING IN LONG PERIOD NW SWELLS ACROSS THE WRN AND CENTRAL WATERS WITH RESULTANT SEAS OF UP TO 14 FT...BUILDING TO 16 FT IN ABOUT 48 HOURS. A HIGH PRES CENTER OF 1022 MB IS ANALYZED AT 26N121W WITH A RIDGE WSW TO 24N140W. THE RIDGE IS FORECAST TO STRENGTHEN SLIGHTLY DURING THE NEXT 24 HRS...THEN WEAKEN INTO 48 HRS. THE HIGH WILL TEND TO BLOCK THE FRONT FROM MOVING TOO FAR S INTO THE AREA...WITH ONLY ITS SRN SEGMENT EXPECTED TO BRUSH TO THE FAR NW WATER TONIGHT AND FRI AS IT DISSIPATES. GAP WINDS... N TO NE GALE FORCE WINDS OBSERVED YESTERDAY INTO THE EARLY AFTERNOON HOURS OF THU AFTERNOON ACROSS THE GULF OF TEHUANTEPEC HAVE DIMINISHED TO 20 TO 25 KT THIS EVENING AS THE TIGHT PRES GRADIENT OVER SE MEXICO SLACKENS. THESE WINDS ARE EXPECTED TO CHANGE LITTLE THROUGH SAT NIGHT WITH SEAS TO 9 FT. AN ASCAT PASS FROM 2326 UTC EARLY THIS EVENING CONFIRMED THAT NE TO E 20-25 KT THROUGH THE GULF OF PANAMA HAVE SIGNIFICANTLY DIMINISHED TO 10-15 KT. THESE WINDS ARE EXPECTED TO REMAIN AT THESE SPEEDS WITH SOME SLIGHT HIGHER FLUCTUATIONS IN THE LATE NIGHT AND EARLY MORNING HOURS. $$ AGUIRRE