000 AXPZ20 KNHC 021602 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT OCT 02 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...ITCZ... AXIS IS CENTERED ALONG 15N97W 10N115W TO 10N125W TO A 1010 MB LOW NEAR 11N137W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE ITCZ BETWEEN 133W-135W. ...DISCUSSION... NEARLY STATIONARY UPPER LEVEL CYCLONIC CIRCULATION JUST N OF THE FAR NE CORNER OF THE AREA NEAR 34N120W HAS A TROUGH EXTENDING SSW TO 24N122W 67N125W...HOWEVER THE ASSOCIATED MOISTURE AND PRECIPITATION REMAINS OVER SOUTHERN CALIFORNIA. THE SURFACE REFLECTION IS NOTED AS A TROUGH FROM 26N121W TO 21N123W. THE TROUGH IS REFLECTED AS A 280 NM WIDE CYCLONIC SWIRL IN THE STRATOCUMULUS CLOUD FIELD. THE UPPER CYCLONIC CIRCULATION CONTINUES TO BE BLOCKED IN BETWEEN A STATIONARY UPPER RIDGE OVER THE WESTERN U.S. THAT EXTENDS SW TO ACROSS SOUTHERN BAJA CALIFORNIA AND SW TO TO AN UPPER ANTICYCLONE NEAR 17N116W. ANOTHER RIDGE EXTENDS FROM THE ANTICYCLONE WNW TO 17N131W. A RIDGE STRETCHES FROM 32N140W SE TO NEAR 25N127W. A RATHER LARGE UPPER TROUGH WAS APPROACHING THE NW CORNER OF THE REGION...WHILE ITS ASSOCIATED SURFACE COLD FRONT WAS JUST CROSSING 32N140W. A JET STREAM BRANCH AHEAD OF THE TROUGH HAS WEAKENED DURING THE PAST 24 HOURS WITH SATELLITE-DERIVED SW WINDS OF 30-50 KT JUST HAVING CROSSED INTO THE FAR NW CORNER OF THE REGION. SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE ALLOWING FOR LIMITED DEEP ATMOSPHERIC MOISTURE OVER MOST OF THIS PORTION OF THE REGION WITH STABLE ENVIRONMENTAL CONDITIONS AS NOTED BY THE MOSTLY OVERCAST STRATOCUMULUS CLOUD FIELD N OF 16N W OF 111W. ITCZ CONVECTION RELATED TO THE ITCZ AND NEAR THE 1010 MB LOW WAS UNDER A DIFFLUENT FLOW ALOFT LOCATED TO THE SW OF THE ANTICYCLONE NEAR 18N137W. OVER THE FAR EASTERN PORTION OF THE AREA...AN UPPER TROUGH EXTENDS FROM EASTERN U.S. SW TO THE WESTERN GULF OF MEXICO TO ACROSS CENTRAL MEXICO AND SW TO NEAR 14N108W. N TO NE UPPER WINDS BEHIND THE TROUGH WITH MODERATE SUBSIDENCE PRESSING SOUTHWARD ARE HAMPERING ANY DEEP CONVECTION THAT ATTEMPTS TO FORM NEAR OR ALONG THE ITCZ THROUGH THE NEXT 48 HOURS. WITH MODERATE SUBSIDENCE LEADING TO DRIER AIR ALOFT BECOMING MORE EVIDENT OVER THE FAR EASTERN PORTION OF THE REGION IN THE WAKE OF THE UPPER TROUGH...THE NOW WEAKENED MONSOON GYRE THAT HAS PERSISTED ACROSS THE FAR EPAC...SRN MEXICO...AND CENTRAL AMERICA DURING THE PAST SEVERAL DAYS WILL ONLY CONTINUE TO BECOME MORE OBSOLETE. TO THE SE OF TROUGH...A MID LEVEL RIDGE AXIS EXTENDS FROM THE N CENTRAL CARIBBEAN SW TO 17N83W AND W TO ACROSS CENTRAL AMERICA AND TO FAR SOUTHEASTERN MEXICO. FAST UPPER LEVEL ELY FLOW ON THE SOUTHERN PERIPHERY OF THE RIDGE IS ADVECTING UPPER LEVEL DEBRIS MOSITURE FROM CLUSTERS OF DEEP CONVECTION OVER THE SW CARIBBEAN SEA...AND EASTERN PACIFIC WESTWARD TO NEAR 108W BUT THINS OUT AS IT SPREADS TOWARDS THE UPPER TROUGH. CROSS-EQUATORIAL S TO SW WINDS INTO THE WEAKER MONSOON TROUGH HAVE DIMINISHED TO LESS THAN 20 KT...HOWEVER SEAS TO 9 FT IN A NW SWELL ARE EVIDENT S OF 10N BETWEEN 120W-133W. THESE SEAS ARE EXPECTED TO BUILD INTO THE 8 TO 10 FT RANGE IN MIXED SW AND NW SWELL S OF 17N BETWEEN 103W-130W...AND IN SW SWELL BETWEEN 92W-103W IN ABOUT 24 HOURS....THEN S OF 15N BETWEEN 92W-120W IN 48 HOURS. N WINDS OF 20 TO 25 KT ARE OCCURRING WITHIN 90 NM EITHER SIDE OF A LINE FROM 16N94.5W TO 13N95.5W...INCLUDING THE ISTHMUS OF TEHUANTEPEC...WITH SEAS TO 9 FT. RIDGING BUILDING SOUTHEASTWARD ACROSS MEXICO WILL TIGHTEN THE PRESSURE GRADIENT OVER SOUTHEASTERN MEXICO AND IN THE ISTHMUS OF TEHUANTEPEC OVER THE NEXT 12 TO 48 HOURS ALLOWING FOR N TO NE WINDS TO INCREASE TO 30-35 KT WITHIN 30 NM OF LINE 16N94.5W TO 14N95W IN 24 HOURS WITH SEAS BUILDING 9 TO 12 FT. THESE GALE WINDS CONTINUE INTO 48 HOURS AT WHICH TIME SEAS ARE FORECAST TO BUILD INTO THE RANGE OF 12 TO 16 FT. ELSEWHERE THROUGH THE ISTHMUS OF TEHUANTEPEC AND VICINITY...WINDS WILL BE N TO NE 20 TO 30 KT THROUGH THE NEXT 48 HOURS WITH SEAS TO 9 FT...BUILDING TO 8 TO 14 FT IN 48 HOURS. OVER THE WESTERN PORTION OF THE REGION W OF A LINE FROM 30N120W TO 15N140W WINDS ARE LESS THAN 20 KT WITH SEAS 8 TO 11 FT IN NW SWELL. THE COLD FRONT JUST CROSSING 32N140W IS FORECAST TO WEAKEN TONIGHT AS IT ENCROACHES INTO THE FAR NW CORNER OF THE AREA. THE MAIN ISSUE HERE WILL BE A LARGE NW SWELL TRAIN THAT WILL SPREAD ACROSS THE NW WATERS IN ABOUT 24 HOURS W OF THE SAME LINE WITH LATEST WAVEWATCH MODEL GUIDANCE BUILDING SEAS UP 11 FT IN 24 HOURS...THEN LOWERS THEM TO 9 TO 10 FT BEYOND TO 48 HOURS. THESE SWELLS ARE FORECAST TO HAVE PERIODS OF 11-13 SEC SAT...SLOWLY DECREASING TO 9-12 SEC SUN AND TO 8-11 SEC MON. $$ AGUIRRE