000 AXPZ20 KNHC 171028 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI SEP 17 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0915 UTC. ...ITCZ... SMALL SEGMENTS OF CONFLUENT FLOW PRODUCING A TRUE ITCZ CAN BE FOUND FROM THE EXTREME SW CARIBBEAN TO 11N86W...AND ALONG 10N W OF 136W. A MONSOON TROUGH EXISTS IN BETWEEN THESE TWO SEGMENTS...EXTENDING FROM 17N104W TO 13N122W TO 10N125W TO 10N134W...WITH EMBEDDED LOWS DESCRIBED BELOW. SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN OCCURRING WITHIN 180 TO 240 NM S OF THESE AXIS E OF 105W...WITH ISOLATED TO SCATTERED MODERATE CONVECTION OCCURRING WITHIN 120 NM S OF THESE AXIS W OF 114W. ...DISCUSSION... A LARGE UPPER LEVEL RIDGE COVERS MUCH OF THE AREA FROM 15N TO 35N BETWEEN 78W AND 124W. A MID TO UPPER LEVEL TROUGH BISECTED N PORTIONS OF THIS RIDGE...EXTENDING FROM SE TEXAS S-SW INTO COASTAL SECTIONS OF NE MEXICO. S OF THE RIDGE...UPPER LEVEL NE TO ELY FLOW PERSISTED ACROSS THE AREA...FROM THE W AND SW CARIBBEAN WWD S OF 18N...EXTENDING TO NEAR 130W. SATELLITE DERIVED WINDS INDICATE MAX WINDS ALOFT 50-55 KT S OF 12N BETWEEN 95W AND 120W. A CLUSTER OF DEEP CNVTN OCCURRING NEAR A 1007 MB LOW CENTER NEAR 14N114W...AND SIMILAR ISOLATED MODERATE TO STRONG CELLS IN THE VICINITY...WERE ACTING TO DIVERT THIS EASTERLY FLOW AND INDUCE DIFFLUENT FLOW ALOFT W OF 112W. A SMALL UPPER ANTICYCLONE WAS CENTERED NEAR 15N134W AND WAS SEPARATED BY THE AFOREMENTIONED RIDGE BY AN INVERTED TROF ALONG 130W. TO THE NW...A LARGE DEEP LAYERED CYCLONE ACROSS THE NE PACIFIC EXTENDED S TO NEAR 35N WITH ASSOCIATED UPPER TROFFING BEGINNING TO INFRINGE UPON NW PORTIONS OF THE AREA. THIS UPPER FEATURE WILL SUPPORT A COLD FRONT MOVING INTO EXTREME NW PORTIONS OF THE AREA TONIGHT THROUGH SAT THAT WILL STALL AND WEAKEN SUN THROUGH MON. SURFACE... A 1019 MB HIGH CENTERED NEAR 28N135W EXTENDS RIDGE NE INTO EXTREME SRN CALIFORNIA OUT AHEAD OF THE APPROACHING COLD FRONT. CROSS HEMISPHERIC ANTICYCLONIC FLOW DOMINATED THE AREA GENERALLY S OF 10N E OF 135W AND WAS FEEDING INTO THE S SIDE OF A WELL ESTABLISHED MONSOON TROUGH OCCURRING BETWEEN THESE TWO HIGHS...BETWEEN 105W AND 135W. THREE CYCLONIC CIRCULATION CENTERS CAN BE SEEN IN SATELLITE IMAGERY THIS MORNING...A BROAD LOW NEAR 12N105W...AND TWO MORE DISTINCT LOWS NEAR 14N114W AND 105N125W. ON THE S SIDE OF THIS ELONGATED MONSOON GYRE...RECENT SCATTEROMETER PASSES HAVE INDICATED BROAD ZONES OF 20 KT SW TO WLY WINDS EXTENDING FROM NEAR 130W TO NEAR 100W...THEN WEAKENING TO LESS THAN 20 KT FROM 100W INTO COSTA RICA AND PANAMA. GLOBAL MODELS MAINTAIN THESE LOW CENTERS WITHIN THE MONSOON CIRCULATION FOR THE NEXT FEW DAYS...WITH THE GFS VERY AGGRESSIVE IN THE STRENGTHENING OF THE EASTERNMOST LOW CURRENTLY NEAR 105W. MODELS SEEM TO AGREE THAT THE EASTERN PORTION OF THE MONSOON GYRE WILL LIFT N TO NEAR THE COAST OF MEXICO NEAR MANZANILLO OVER THE WEEKEND...LIKELY INFLUENCED BY THE WEAKNESS BEING CARVED OUT BY HURRICANE KARL. THIS WILL MAINTAINS A BROAD ZONE OF 20 KT SW FLOW S OF THIS PERSISTENT TROUGH THROUGH AT LEAST MON...AND ALSO HELP TO PRODUCE A MODEST PRES GRADIENT ALONG THE W COAST OF CALIFORNIA INTO BAJA...CAUSING 20 KT NWLY WINDS ALONG THE COASTS OF SRN CALIFORNIA AND BAJA TO EXPAND W SUN INTO MON. MARINE... SEAS ASSOCIATED WITH THE SWLY FLOW S OF THE LOWS MENTIONED ABOVE ARE EXPECTED TO CONTINUE TO MIX WITH SRN HEMI LONG PERIOD SW SWELL THROUGH THE WEEKEND TO PRODUCE 9 TO 12 FT SEAS THROUGHOUT THE AREA OF 20 KT SW WINDS. THIS LONG PERIOD SWELL WILL PEAK ACROSS THE AREA WATERS TODAY BEFORE GRADUALLY FADING THROUGH THE WEEKEND. $$ STRIPLING