000 AXPZ20 KNHC 030928 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU APR 03 2008 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... ITCZ AXIS IS CENTERED ALONG AXIS AXIS 06N78W 02N93W 03N114W 07N133W 06N140W. ISOLATED MODERATE WITHIN 120 NM S OF AXIS FROM 117W TO 126W. WIDELY SCATTERED MODERATE WITHIN 180 NM N OF AXIS FROM 131W TO 136W AND WITHIN 60 NM N OF AXIS BETWEEN 138W AND 140W. ...DISCUSSION... A WEAKENING CLOSED CYCLONE APPROACHING SOUTHERN CALIFORNIA SHOULD SHEAR EASTWARD TODAY...ONLY TO BECOME ABSORBED IN A LARGER-SCALE TROUGH CROSSING THE INTERMOUNTAIN WEST AND PLAINS. AN ASSOCIATED SURFACE LOW AND A FORMER GALE CENTER IS CENTERED NEAR 34N125W AND DRIFTING E...AS THE REMAINS OF A COLD FRONT DANGLE SOUTHWARD FROM 31N120W TO 26N124W. ALTHOUGH A WEAK ANTICYCLONIC FLOW NOW COVERS THE AREA N OF 20N AND W OF 120W ...A ONCE STRONGER NWLY FLOW IN THE WAKE OF THIS SYSTEM IS RESPONSIBLE FOR 8 TO 9 FT NW SWELL...WHICH CONTINUES TO ARRIVE OVER THE FAR NW PART OF THE AREA. ELSEWHERE...A 0340 UTC QUIKSCAT SHOWS A NEW STATIONARY FRONT ENTERING THE FAR NW...ASSOCIATED WITH ANOTHER...DEEPER CLOSED CYCLONE SINKING SOUTHWARD NW OF THE AREA ALONG 147W. AN ASSOCIATED...DEVELOPING GALE CENTER SHOULD ALSO REMAIN NW OF THE AREA THE NEXT FEW DAYS...WHILE AN E TO SE FLOW TO 20 KT FORMS BETWEEN IT AND HIGH PRES FORMING OFFSHORE THE CALIFORNIA COAST. THIS SHOULD HELP KEEP SEAS AROUND 8 TO 9 FT N OF 22N W OF 136W INTO FRI AND SAT IN LONG PERIOD NW SWELL AND NEWLY-GENERATED E WIND WAVES. TO THE SOUTH...RECENT QUIKSCAT PASSES REVEAL WEAKER TRADES FROM 10N TO 20N AND W OF 120W...COMPARED TO THOSE OBSERVED THE LAST FEW DAYS. IN FACT...ONLY A FEW 20-KT NELY WINDS WERE DETECTED ACROSS THIS REGION...WITH SEAS GENERALLY RUNNING BETWEEN 5 AND 7 FT IN MIXED LONG PERIOD NW SWELL COMING OUT OF THE FAR N PACIFIC AND EVEN LONGER PERIOD S TO SE SWELL WITH ORIGINS FROM THE SOUTHERN HEMISPHERE. MODEL GUIDANCE SUGGESTS THAT HIGH PRESSURE SHOULD BUILD OFFSHORE THE CALIFORNIA COAST FRI IN THE WAKE OF THE SHORTWAVE MOVING INLAND OVER THE SW CONUS TODAY. THE ASSOCIATED ...STRONGER PRESSURE GRADIENT OVER THE TROPICAL EAST PACIFIC W OF ABOUT 120W SHOULD RESULT IN A SUBTLE INCREASE TO TRADES ROUGHLY IN THE BAND FROM 10N TO 20N. IN THE END...THIS SHOULD LEAD TO 6 TO POSSIBLY 8 FT SEAS ACROSS THIS REGION BY FRI AND SAT PRIMARILY IN NE WIND WAVES. E OF 120W... AS THE WEAKENING CLOSED CYCLONE HEADS INLAND OVER THE SW CONUS TODAY...BUILDING HEIGHTS ALOFT SHOULD LEAD TO INCREASING SURFACE PRESSURES NEAR AND W OF THE BAJA PENINSULA. THE INCREASED PRESSURE GRADIENT ACROSS THE REGION SHOULD FAVOR NW TO N WINDS INCREASING TO 20 TO 25 KT LATER TODAY INTO FRI W OF THE SOUTHERN AND CENTRAL BAJA PENINSULA...WITH SLIGHTLY WEAKER WINDS TO 20 KT OVER THE SOUTHERN HALF OF THE GULF OF CALIFORNIA. ALTHOUGH ONLY A BRIEF BURST...SEAS SHOULD BUILD TO 8 FT IMMEDIATELY W OF THE SOUTHERN TIP OF THE BAJA PENINSULA IN SW TO W SWELL. SEAS COULD ALSO BRIEFLY BUILD TO 8 FT S OF 23N AND E OF 110W FRI IN NW WIND WAVES. ELSEWHERE...A STRONG...MID- TO UPPER-LEVEL ANTICYCLONE JUST SW OF MEXICO CONTINUES TO DOMINATE THE AREA FROM CENTRAL AMERICA TO 120W S OF 20N. WATER VAPOR IMAGERY CONTINUES TO INDICATE STRONG SUBSIDENCE UNDERNEATH THE RIDGE ACROSS THIS AREA...INHIBITING NOT ONLY ANY CONVECTION BUT NEARLY ALL CLOUD COVER. REAL TIME NCEP RE-ANALYSIS DATA SHOW A BAND OF 20- TO 25-KT ANOMALOUS ELY FLOW LIES SOUTH OF THE RIDGE FROM ABOUT 90W TO 110W. MODELS SHOW THE STRONG RIDGE MIGRATING WESTWARD THE NEXT FEW DAYS AS HEIGHTS LOWER OVER MEXICO AND THE GULF OF MEXICO BY EARLY THIS WEEKEND...WITH THE RIDGE LIKELY TO BE CLOSER TO 18N116W BY LATE SAT. FINALLY...A SHORT-LIVED AND FAIRLY WEAK GAP WIND EVENT IN THE GULF OF PAPAGAYO FROM YESTERDAY APPEARS OVER NOW GIVEN RECENT QUIKSCAT IMAGERY. HOWEVER...HIGHER-RESOLUTION QUIKSCAT DATA FROM THIS EVENING STILL INDICATES ELY 20 KT WINDS WITHIN ABOUT 30 NM OF THE COAST. $$ KIMBERLAIN