000 AXPZ20 KNHC 132151 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN SEP 13 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...TROPICAL WAVES... TROPICAL WAVE WAS ANALYZED ALONG 95W FROM 06-19N MOVING W 15 KT. TROPICAL WAVE WAS ANALYZED ALONG 112W FROM 05-17N MOVING W 10 TO 15 KT. ...THE ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG THE LINE 09N79W TO 12N90W TO 15N103W TO 12N114W TO 10N122W TO 07N130W TO 07N140W. SCATTERED STRONG WITHIN 180 NM S OF THE AXIS BETWEEN 101W AND 107W AND WITHIN 30 NM OF THE AXIS BETWEEN 123W AND 125W. SCATTERED MODERATE ISOLATED STRONG WITHIN 120 NM S OF THE AXIS BETWEEN 110W AND 113W AND BETWEEN 115W AND 118W. SCATTERED MODERATE WITHIN 120 NM S OF THE AXIS BETWEEN 123W AND 127W AND 130W AND 132W. ...DISCUSSION... SHARPENING MID TO UPPER TROUGH OVER THE NORTHWEST PART OF THE AREA EXTENDS FROM AN ELONGATED LOW CENTERED NEAR 40N128W S TO 30N125W THEN SW AND W ALONG 25N BEYOND 140W. THIS IS SUPPORTING A MEANDERING COLD FRONT THAT LAGS BEHIND THIS UPPER TROUGH A FEW DEGREES TO THE NW. THE AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS WITH BROKEN STRATOCUMULUS IN THE LOWER LEVELS. THE TROUGH IS FORECAST TO MOVE EAST AND BE REPLACED BY NEAR ZONAL FLOW IN THE NEXT DAY OR TWO. THE COLD FRONT IS FORECAST TO WEAKEN AS IT MOVES EAST BECOMING DIFFUSE SOUTH OF 32N MONDAY. LONG PERIOD NWLY SWELLS GENERATED BEHIND THIS FRONT HAVE ALREADY PROPAGATED INTO NW PORTIONS OF THE AREA AND HAVE REACHED ALONG A LINE ROUGHLY FROM SOUTHERN BAJA CALIFORNIA TO THE EQUATOR ALONG 140W. THIS PULSE OF NW SWELL WILL CONTINUE SE ACROSS THE AREA TONIGHT...ALLOWING FOR SEAS TO PEAK AT AROUND 9 FT ACROSS THE NW HALF OF THE AREA...AND 10 OF 11 FT IN THE VICINITY OF THE REMNANTS OF LINDA NEAR 21N133W...WHERE NELY WIND WAVES ARE MIXING WITH THIS LONG PERIOD NW SWELL. A LARGE UPPER LOW AND ASSOCIATED L/W TROUGH SWEEPING ACROSS THE FAR NE PACIFIC WILL SWEEP E ACROSS THE PACIFIC WATERS JUST NW OF THE AREA MON AND TUE...AND SUPPORT A STRONGER COLD FRONT...PRESENTLY WELL NW OF THE AREA...INTO THE FAR NW PORTION OF THE AREA LATE MON NIGHT INTO TUE...PRECEDED BY INCREASING SLY WINDS AND BUILDING SEAS. ANOTHER MID TO UPPER TROUGH EXTENDS SOUTH INTO THE GULF OF MEXICO FROM A DEEP LAYERED CYCLONIC CIRCULATION OVER E TEXAS. THE TROUGH EXTENDS FROM S TEXAS INTO THE BAY OF CAMPECHE AND THEN WEAKLY INTO MEXICO ALONG 93W. ZONAL UPPER LEVEL FLOW IS GENERALLY ACROSS THE AREA N OF 25N E OF 130W. CONVECTION HAS BEGUN TO DEVELOP OVER THE SIERRA MADRE OCCIDENTAL DURING THE AFTERNOON AND IS LIKELY DUE TO LINGER THROUGH THE EVENING. BETWEEN THE TWO ABOVE TROUGHS A LARGE BROAD ANTICYCLONIC CIRCULATION DOMINATES THE FLOW...RIDGING E TO W ALONG ABOUT 18N 10 130W. DIFFLUENT FLOW ALOFT S THROUGH SE OF THIS RIDGE CONTINUE TO VENTILATE CONVECTION ASSOCIATED WITH THE MONSOONAL CIRCULATION BETWEEN 98W AND 112W...AND THIS AREA WILL REMAIN QUITE ACTIVE CONVECTIVELY FOR THE NEXT DAY OR SO. IN FACT...A LARGE SWATH OF 20-30 KT SELY WIND ACROSS THE SE PACIFIC IS CROSSING THE EQUATOR...AND PRODUCING A 20-25 KT ANTICYCLONIC FLOW INTO THE S SIDE OF THIS EPAC MONSOON TROUGH AND ITCZ TO THE E...YIELDING A SUBSTANTIAL AREA OF 20-25 KT S TO SW WINDS AND 8-12 FT SEAS ON THE S SIDE OF THIS TROUGH...AND AIDING IN STRONG LOW LEVEL CONVERGENCE AND PERSISTENT DEEP CONVECTION. GLOBAL MODELS HAVE BEEN KEYING IN ON THE POSSIBLE DEVELOPMENT OF A LOW PRESSURE SYSTEM IN THIS REGION AS THIS CROSS HEMISPHERIC FLOW LIFTS THE E END OF MONSOON TROUGH/ITCZ NWD TO NEAR THE MEXICAN COASTLINE BETWEEN BY 48 HOURS. OTHERWISE...A FLAT PRESSURE GRADIENT IS OBSERVED AT THE SURFACE WITH A WEAK RIDGE BETWEEN THE LOW THAT IS THE REMNANT OF LINDA NEAR 21N133W AND THE COLD FRONT OVER THE FAR NORTHWEST PART. $$ STRIPLING