000 AXPZ20 KNHC 232159 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN MAY 23 2010 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. ...TROPICAL WAVES... TROPICAL WAVE ANALYZED EARLIER ALONG ITCZ 118/119W WAS DROPPED FROM THE 18 UTC SFC ANALYSIS...HOWEVER A SUBSEQUENT 1802 UTC HIGH RESOLUTION ASCAT PASS SUGGESTED EVIDENCE OF ITS EXISTENCE ALONG 121W/122W WITH WELL DEFINED TURNING IN THE ASCAT WIND VECTORS ALONG THE WAVE AXIS. THIS FEATURE WILL BE REINTRODUCED ON THE 00Z SFC ANALYSIS. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 09N84W TO 11N90W TO 08N128W TO 07N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 150-180 NM S OF AXIS BETWEEN 85W AND 96W...AND WITHIN 90-120 NM EITHER SIDE OF THE AXIS BETWEEN 96W AND 104W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS WITHIN 90-120 NM EITHER SIDE OF AXIS BETWEEN 125W AND 135W. ...DISCUSSION... A LARGE RIDGE DOMINATES THE EPAC S OF 40N W OF 110W...CENTERED ON A STATIONARY 1036 MB HIGH PRES CENTER NEAR 34N150W. A TIGHT PRES GRADIENT REMAINS IN PLACE BETWEEN THIS RIDGE AND LOW PRES ACROSS THE DESERT SW OF THE U.S. FRESH NW TO N WINDS IN THE 20-25 KT RANGE...ACCORDING TO THE 1758 UTC ASCAT PASS...HAVE EXPANDED TO COVER THE AREA N OF 20N E OF 135W. SHIP ZCDT7 REPORTED NW WINDS OF 33 KT NEAR 27N115W AT 2100 UTC...HOWEVER A QUICK QC OF THE SHIP INDICATED WINDS WERE ABOUT 5-8 KT TOO HIGH. THE STRONG PRES GRADIENT OVER NE WATERS WILL BE MAINTAINED THE NEXT FEW DAYS WITH THE MAIN PATTERN CHANGE BEING A SHIFT E IN THE PRES GRADIENT...ALLOWING THE 20-25 KT WINDS TO GRADUALLY CONTRACT E TOWARD THE COAST. THE EASTWARD SHIFTING GRADIENT SHOULD ALSO INCREASE THE NW TO N WINDS IN THE GULF OF CALIFORNIA TO 20 KT BY EARLY MON MORNING. LOOK FOR NE TRADE WINDS BETWEEN THE RIDGE AND THE ITCZ...CURRENTLY IN THE 20-25 KT RANGE ACCORDING TO THE 1800 UTC ASCAT PASS...TO REMAIN IN PLACE GENERALLY W OF 128W FOR THE NEXT TWO DAYS. A 60-80 KT SOUTHERN STREAM UPPER JET EXTENDS FROM 17N131W TO 23N120W THEN E ACROSS EXTREME SRN BAJA CALIFORNIA. THE DIFFLUENT RIGHT REAR QUADRANT OF THIS UPPER JET IS ENHANCING DEEP CONVECTION ALONG THE ITCZ BETWEEN 125W AND 135W. SOME CONVECTIVE BLOW OFF FROM THE ITCZ IS BEING TRANSPORTED TO THE NE BY THIS JET. S OF THIS JET AND BROAD SW TO WLY FLOW ALOFT DOMINATING MOST OF THE AREA...PULSING MODERATE TO STRONG ITCZ CONVECTION ALONG THE ITCZ CONTINUES TO MAINTAIN AN UPPER RIDGE ALONG ABOUT 12N BETWEEN 95W AND 120W. A BROAD LOW LEVEL CYCLONIC GYRE PERSISTS FROM COLOMBIA W TO 94W WITH A LOW TO MID LEVEL CYCLONIC CIRCULATION HAVING DEVELOPED OVER NICARAGUA AND HONDURAS AND THE ADJACENT WATERS OF THE PAST 2 DAYS. WIDESPREAD CONVECTION...MUCH OF IT MODERATE TO STRONG...WILL PERSIST ACROSS THIS PORTIONS OF CENTRAL AMERICA FOR THE NEXT COUPLE OF DAYS AS ABUNDANT MOISTURE CONTINUES TO CONVERGE ACROSS THIS AREA...ASSOCIATED WITH THE LATTER CYCLONIC CIRCULATION. THIS LOW IS FORECAST TO DRIFT VERY SLOWLY SW OF THE NEXT FEW DAYS AND WILL CONTINUE TO FORCE ITCZ CONVECTION INTO THE W COASTS OF COSTA RICA AND WRN PANAMA. LARGE CROSS-EQUATORIAL LONG PERIOD SW SWELL CONTINUES TO IMPACT MUCH OF THE PACIFIC COASTLINE WITHIN THE FORECAST AREA. DEEP WATER WAVE HEIGHTS ARE IN THE 8-10 FT RANGE AT 14-17 SECONDS PER WAVEWATCH GUIDANCE. OFFSHORE OF BAJA CALIFORNIA THESE LONG PERIOD SWELL ARE MIXING WITH NW WIND WAVES THAT HAVE DRIVEN SEAS UP TO 13 FT. THE SW SWELLS WILL BEGIN TO FADE BY TONIGHT... REACHING 6-8 FT IN 12-14 SECOND PERIODS BY MON NIGHT. A NEW PULSE OF LONG PERIOD CROSS-EQUATORIAL SWELL WILL MOVE INTO S WATERS MON. $$ COBB