000 AXPZ20 KNHC 292206 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC TUE SEP 29 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 2130 UTC. ...SPECIAL FEATURES... UNDERNEATH AND TO THE S OF A LARGE UPPER LEVEL HIGH ALONG THE W COAST OF MEXICO HAS EVOLVED A LARGE AND BROAD CYCLONIC CIRCULATION IN THE LOW TO MID LEVELS...PORTIONS OF WHICH HAVE BEEN TRACKED FOR DAYS MOVING ACROSS THE FAR W CARIB...CENTRAL AMERICA...AND THEN S CENTRAL MEXICO AND THE ADJACENT PACIFIC. SATELLITE IMAGERY THIS AFTERNOON SHOWS AN ELONGATED AND BROAD CYCLONIC CIRCULATION...FROM NEAR 21N111W TO NEAR 12N107W. A 1007 MB SURFACE LOW WAS ANALYZED NEAR 16N109W AT 18Z...WHILE SATELLITE IMAGERY SUGGESTED TWO MID LEVEL CIRCULATIONS OCCURRING IN EACH END OF THIS ELONGATED CIRCULATION. THIS LARGE CIRCULATION HAS ENTRAINED ABUNDANT TROPICAL MOISTURE AND IS FORECAST BY GLOBAL MODELS TO SHIFT NW OVER THE NEXT FEW DAYS AND GAIN BETTER ORGANIZATION. THERE IS A MODERATE CHANCE FOR TROPICAL CYCLONE DEVELOPMENT WITHIN THIS SYSTEM. A BROAD AREA OF 20-25 KT WINDS CONTINUES TO BE INDICATED BY A PARTIAL MORNING QUIKSCAT PASSAGE ACROSS THE NE SEMICIRCLE OF THIS CIRCULATION... WHERE SEAS ARE LIKELY NEARING 10 FT. ...TROPICAL WAVE... A TROPICAL WAVE WAS ANALYZED ALONG 96W MOVING W 10-15 KT. CYCLONIC TURNING WAS NOTED IN THE LOW TO MID CLOUDS ACROSS THIS AREA AND IN RECENT TPW ANIMATIONS. ISOLATED TO MODERATE CONVECTION WAS OCCURRING S OF 13N BETWEEN 94W AND 101W...BEING ENHANCED BY A MID TO UPPER LOW TO THE NW. ...ITCZ... AXIS WAS ALONG 09N84W TO 11N99W TO NEAR 16N109W...THEN RESUMES FROM 16N114W TO 12N122W TO 14N132W TO 12N140W. SCATTERED MODERATE ISOLATED STRONG FROM 06N TO 13N BETWEEN 97W AND 103W. SCATTERED MODERATE WITHIN 180 NM S OF THE AXIS BETWEEN 124W AND 130W AND WITHIN 120 NM N OF THE AXIS W OF 137W. ...DISCUSSION... A L/W TROUGH HAS SWEPT ACROSS THE FAR NE PACIFIC THE PAST COUPLE OF DAYS...AND LINKED WITH AN ELONGATING SW-NE ALIGNED UPPER LEVEL CYCLONIC CIRCULATION ACROSS NW PORTIONS OF THE AREA...EFFECTING A NARROWING TROUGH FROM THE PACIFIC NW OF THE U.S. THROUGH 30N130W TO A SERIES OF VORT LOBES EXTENDING SW THEN W ALONG 24N THEN CONTINUING NW BEYOND 30N155W. THE BASE OF THIS TROUGH IS VERY BROAD AND IS STILL CARVED OUT INTO THE NRN FRINGES OF THE TROPICS...EXTENDING FROM 16-20N BETWEEN 125W AND 152W. A 50-60 KT JET AXIS WAS MOVING THROUGH THE BACK SIDE OF THE BROAD TROUGH AND THROUGH THE BASE ALONG 18-21N...AND WAS EXITING AS A BROADER 60-80 KT JET ON THE E SIDE OF THIS AXIS LIFTING OUT AND INTO SRN CALIFORNIA AND THE WRN U.S. THIS UPPER TROUGH WILL MAINTAIN A SW-NE ELONGATION OVER THE NEXT FEW DAYS AS A BROAD OMEGA BLOCKING UPPER PATTERN SPANS N AMERICA. DOWNSTREAM...AN AMPLIFYING BLOCKING UPPER LEVEL RIDGE WAS LOCATED SE OF THE CYCLONIC CIRCULATION...AND EXTENDED FROM A LARGE ANTICYCLONE OVER WRN MEXICO NEAR 22N106W ESE INTO THE SRN GULF OF MEXICO AND WRN CARIBBEAN...AND SW THROUGH 20N118W TO A COL NEAR 12N136W AND THEN CONNECTED TO ANOTHER UPPER ANTICYCLONE CENTERED OVER THE S CENTRAL PACIFIC NEAR 13N158W. GENERALLY DRY AND SUBSIDENT CONDITIONS COULD BE FOUND ACROSS THE BASE OF THE UPPER TROUGH...AND ACROSS THE NW AND NRN FLANKS OF THE RIDGE...JUST SE OF THE SUBTROPICAL JET. A MID TO UPPER LEVEL CYCLONIC CIRCULATION WAS NOTED NEAR 13N101W AND EXTENDED S AS A TROUGH INTO THE ITCZ...MOVING SW AT 20 KT AWAY FROM COASTAL MEXICO AND ACROSS ADJACENT TROPICAL EPAC. THIS SYSTEM WAS PRODUCING SCATTERED MODERATE TO STRONG CONVECTION ACROSS THE EPAC TO THE E AND SE. AN AREA OF BROAD AND MODEST LOW TO MID LEVEL CYCLONIC TURNING WAS NOTED JUST TO THE SE OF THIS FEATURE...ALONG 97/98W...LIKELY THE TROPICAL WAVE ANALYZED A BIT FURTHER TO THE E EARLIER TODAY. AT THE SURFACE...A HIGH PRES RIDGE EXTENDED FROM A 1036 MB HIGH LOW NEAR 42N148W SE TO OFFSHORE OF BAJA CALIFORNIA NEAR 24N114W. THE ITCZ CONTINUED TO BE QUITE ACTIVE ACROSS SEVERAL ZONES IN THE AREA...UNDER GOOD DIFFLUENCE ALOFT. SEVERAL WAVES...LOWS AND PERTURBATIONS WERE EVIDENT IN SHORT WAVE INFRARED SATELLITE IMAGERY OVERNIGHT. FIRST THE BROAD LOW AND CONVECTION OFF OF MEXICO...ANOTHER LARGE CYCLONIC CIRCULATION CENTERED NEAR 13.5N121.5W...AND THE REMNANTS OF NORA...A BENIGN 1010 MB LOW NEAR 15N133W. REGIONAL SEAS ARE BEING DOMINATED BY MODERATE PERIOD SRN HEMISPHERE SE SWELL...AND LONGER PERIOD NW AND SSW SWELL. THE FRESH TO STRONG E TO SE FLOW ALONG THE MEXICAN COAST WAS GENERATING SEAS OF 7 TO 10 FT IN THIS CONFUSED MIX. SEAS IN EXCESS OF 8 FT WILL GRADUALLY PROPAGATE NWD ACROSS THE EQUATOR TO 12N BY MID WEEK AS SEVERAL NEW PULSES OF LARGE SE AND SW SWELL MOVE INTO THE AREA. $$ STRIPLING