000 AXPZ20 KNHC 092156 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI NOV 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS SW FROM THE COAST OF COSTA RICA AT 09N84W TO 07N89W...THEN WIGGLES WESTWARD THROUGH POINTS 08N96W TO 07N104W TO 10N116W TO 08N126W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ...WHICH CONTINUES W TO BEYOND 08N140W. SCATTERED STRONG CONVECTION IS OBSERVED WITHIN 90 NM OF 03N79W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE OF A LINE FROM 06N89W TO 09N98W...AND WITHIN 60 NM EITHER SIDE OF A LINE FROM FROM 11N110W TO 08N118W TO 06N140W...AND WITHIN 75 NM EITHER SIDE OF A LINE FROM 16N111W TO 12N116W. ...DISCUSSION... A LONGWAVE UPPER TROUGH OVER WESTERN N AMERICA CONTINUES S INTO THE DISCUSSION AREA FROM 32N120W TO 18N120W. A REINFORCING SHORTWAVE TROUGH IS MOVING THROUGH THE LONGWAVE PATTERN FROM 32N123W TO 27N130W CONTINUING SW INTO AN UPPER CYCLONE AT 24N142W. THIS PATTERNS SETS UP A SOUTHWESTERLY UPPER JET ACROSS THE DISCUSSION AREA WITHIN ABOUT 360 NM EITHER SIDE OF A LINE FROM 16N140W TO 32N109W WITH A SECOND UPPER WESTERLY JET ROTATING THROUGH THE UPPER TROUGH ACROSS THE AREA N OF 28N BETWEEN 127W-113W MERGING WITH THE SW JET. THESE UPPER WINDS ARE ADVECTING UPPER MOISTURE E OVER THE DISCUSSION AREA FROM 10N-24N BETWEEN 143W-122W. WEAK UPPER DIFFLUENCE IS INDICATED OVER THE DEEP TROPICS S OF 12N W OF 115W AND IS ENHANCING THE CONVECTION ALONG THE MONSOON TROUGH AND ITCZ W OF 115W WITH THE DEBRIS MOISTURE ADVECTED SE ACROSS THE EQUATOR BETWEEN 115W-135W. AN UPPER LEVEL ANTICYCLONE IS CENTERED AT 08N96W WITH AN UPPER RIDGE EXTENDING N ACROSS CENTRAL AMERICA AND THE WESTERN GULF OF MEXICO...AND CONTINUING N ACROSS CENTRAL N AMERICA. UPPER DIFFLUENCE ALONG THE W PERIPHERY OF THE ANTICYCLONE ENHANCED THE AREA OF CONVECTION FROM 12N-16N AS PREVIOUSLY DESCRIBED. THE DEBRIS MOISTURE IS ADVECTED N AND NE AROUND THE UPPER RIDGE ACROSS OLD MEXICO NEAR 22N104W. THE REINFORCED UPPER TROUGH WILL PROGRESS E ACROSS THE WESTERN CONUS THROUGH THE WEEKEND MAINTAINING THE UPPER WESTERLY FLOW ACROSS THE DISCUSSION AREA GENERALLY TO THE N OF 11N. THE UPPER CYCLONE AT 24N142W WILL CUT OFF AND GRADUALLY FILL THROUGH SUN NIGHT. AN INVERTED UPPER TROUGH CURRENTLY DEVELOPING OVER THE DEEP TROPICS S OF 08N ALONG 109W WILL SHIFT WESTWARD AND DEEPEN INTO AN UPPER CYCLONE AT 02N112W LATE SAT NIGHT. THIS UPPER TROUGH/CYCLONE WILL EFFECTIVELY SEPARATE THE UPPER FLOW OVER THE SOUTHERN PORTION OF THE DISCUSSION AREA. AS THE UPPER TROUGH SHIFTS EASTWARD IT WILL DRAG A WEAK SURFACE COLD FRONT ACROSS THE NE WATERS TONIGHT THROUGH SAT NIGHT ACCOMPANIED BY SW-W-NW 10-15 KT WIND SHIFT. STRONG HIGH PRESSURE WILL BUILD S ACROSS THE N-CENTRAL WATERS IN THE WAKE OF INCREASING THE WINDS AROUND THE RIDGE TO MOSTLY 15-20 KT BUT INCREASING TO 20-25 KT IN THE AREA FROM 10-15N BETWEEN 120-130W SUN AFTERNOON. THIS INCREASING PRESSURE GRADIENT WILL ARRIVE THE W COAST OF THE NORTHERN BAJA PENINSULA IN THE FORM OF NW 15-20 KT WINDS THIS EVENING...WITH SEAS OF 6-8 FT IN NW SWELL ARRIVING ON SAT. THESE CONDITIONS WILL SPREAD S ALONG THE ENTIRE W COAST OF BAJA ON SUN. EXPECT A SW-W WIND SHIFT ALONG THE WEAK COLD FRONT OVER THE GULF OF CALIFORNIA TO THE N OF 29N ON TONIGHT AND EARLY SAT MORNING WITH NW WINDS 1T 15-25 KT ACROSS THE ENTIRE GULF OF CALIFORNIA SUN NIGHT THROUGH MON NIGHT. GAP WINDS...MINIMAL GALE CONDITIONS DIMINISHED A FEW HOURS EARLIER THIS AFTER S DROPPED THE GULF OF TEHUANTEPEC GALE AT 18Z. RESIDUAL WIND/SEAS WILL DIMINISH/SUBSIDE THIS WEEKEND WITH THE NORTHERLY SWELLS MIXING WITH CROSS EQUATORIAL SW SWELL ACROSS THE TROPICS FROM ABOUT 05N-14N BETWEEN 94W-112W THIS WEEKEND. EXPECT THE NE 20-25 KT WINDS IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO TO PULSE THROUGH SUN AFTERNOON. THE RESULTANT NE SWELL WILL PROPAGATE W TO ALONG 94W...MERGING WITH THE SWELL ORIGINATING FROM THE NORTHERLY WINDS SURGING THROUGH THE GULF OF TEHUANTEPEC. NLY WINDS WILL AGAIN SURGE INTO THE GULF OF TEHUANTEPEC LATE MON AND RAPIDLY INCREASE TO GALE FORCE MON EVENING. THIS WILL BE A LONG TERM EVENT LASTING THROUGH NEXT FRI MORNING. $$ NELSON