000 AXPZ20 KNHC 140251 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE SEP 14 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0200 UTC. ...ITCZ... ITCZ AXIS ACROSS THE EPAC IS BETTER CHARACTERIZED AS AN ELONGATED MONSOONAL TROUGH WITH CONVERGENCE AND CONVECTION OCCURRING IN CLASSIC FASHION ON THE S SIDE IN THE CONFLUENT SW TO W WIND FLOW. THIS AXIS WAS ANALYZED FROM 09N90W TO DEVELOPING LOW NEAR 10.5N97W 1008 MB TO LOW NEAR 10.5N113W 1008 MB TO LOW NEAR 11N124W 1008 MB TO LOW NEAR 10N136W 1011 MB TO 10N140W AND BEYOND. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED WITHIN 60 NM N AND 120 NM S OF TROUGH AXIS E OF 120W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 90 NM EITHER SIDE OF TROUGH W OF 126W. ...DISCUSSION... AN EXPANSIVE ANTICYCLONE CENTERED OVER SE TEXAS EXTENDS A RIDGE SOUTHWEST THROUGH A NEWLY DEVELOPING ANTICYCLONE OVER THE SOUTHERN GULF OF CALIFORNIA NEAR 26N109W AND CONTINUES TO 20N122W. A MID TO UPPER LEVEL PERTURBATION EMBEDDED IN THE SLY FLOW ON THE W PORTION OF THE RIDGE HAS ACTED TO SIGNIFICANTLY ENHANCE LATE AFTERNOON CONVECTION ALONG THE W SLOPES OF THE SIERRA MADRE OCCIDENTALES EXTENDING W OUT OVER THE GULF OF CALIFORNIA. THIS CONVECTION HAS MOVED RATHER QUICKLY N THIS EVENING BUT HAS BEGUN TO DIMINISH RECENTLY...ESPECIALLY OVER THE GULF. EASTERLY UPPER LEVEL FLOW ON THE S SIDE OF THE RIDGE DOMINATES THE AREA S OF 20N FROM THE W CARIBBEAN W TO 120W. ISOLATED TO SCATTERED AREAS OF DEEP CONVECTION ARE OCCURRING ON THE S SIDE OF THE EPAC MONSOON TROUGH...IN THE SW TO W LLVL FLOW...WITH THE UPPER LEVEL FLOW BECOMING DIVERGENT AROUND THESE ISOLATED HOT TOWERS. N WINDS TO 25 KT ARE FUNNELING THROUGH THE ISTHMUS OF TEHAUNTEPEC AND ARE THEN BEING DIVERTED SW TO 102W...WRAPPING AROUND THE W SIDE OF A LOW TO MID LEVEL CYCLONIC SWIRL CURRENTLY CROSSING 100W. THESE WINDS THROUGH TEHAUNTEPEC ARE EXPECTED TO BE REMAIN AROUND 20 KT THROUGH TUE NIGHT AS A SURFACE TROUGH LINGERS FROM THE SW GULF OF MEXICO INTO THE ISTHMUS...DIRECTING NORTHERLY FLOW ON ITS W SIDE FROM HIGHER PRES OVER EASTERN MEXICO NEAR 20N SOUTHWARD INTO THE EASTERN PACIFIC. A SW TO W UPPER JET LIES OVER FAR N WATERS. THIS MOSTLY ZONAL FLOW LIES BEHIND A MEAN TROUGH WHOSE LEADING EDGE IS NEAR THE CALIFORNIA COAST. THE REFLECTION OF THIS TROUGHING AT THE SURFACE IS EXPANDING THE USUAL TROUGHING OVER THE GULF OF CALIFORNIA NORTHWARD INTO CALIFORNIA AND OFFSHORE. THE PRES GRADIENT BETWEEN THIS TROUGHING AND THE SUBTROPICAL RIDGE...WHICH LIES FROM A 1023 MB HIGH NEAR 33N140W TO 20N113W...IS YIELDING NW TO N WINDS IN THE 15 TO 20 KT RANGE OFF THE COAST OF NORTHERN BAJA CALIFORNIA ACCORDING TO SHIPS MQPF2 NEAR 26N116W REPORTING 18 KT AND UNKNOWN SHIP NEAR 26N117W REPORTING 18 KT AT 1800 UTC. THIS FRESH COASTAL FLOW IS EXPECTED TO MAXIMIZE DURING THE EVENING AND OVERNIGHT HOURS AND CONTINUE THROUGH THE NEXT FEW DAYS. LONG PERIOD SRN HEMI SWELL HAS BEGUN TO CROSS THE EQUATOR IN THE PAST 24 HOURS...WITH A NEW PULSE CURRENTLY REACHING THE EQUATOR ACROSS W PORTIONS. THIS NEXT PULSE OF LARGE SW SWELL WILL RAISE TOTAL SEA HEIGHTS TO 8 FT AND GREATER TO NEAR 10N BY WED EVENING...AND GENERATE LARGE AND STRONG SURF ALONG THE EXPOSED PACIFIC COASTS DURING THE NEXT FEW DAYS. $$ STRIPLING