000 AXPZ20 KNHC 152132 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN MAY 15 2011 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 2100 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 08N112W TO 06N120W TO 03N131W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 180 NM S OF THE AXIS BETWEEN 112W AND 123W AND WITHIN 75 NM EITHER SIDE OF THE AXIS BETWEEN 123W AND 128W. ...DISCUSSION... AN UPPER LEVEL TROUGH DOMINATES THE WESTERN SEABOARD OF N AMERICA WITH A DEEP LAYERED CYCLONE NEAR 42N126W AND A MID TO UPPER TROUGH EXTENDING S OVER THE DISCUSSION AREA FROM THIS CYCLONE THROUGH 32N127W TO A BASE OVER THE TROPICS NEAR 16N136W. THE DEEP LAYERED LOW IS REFLECTED AT THE SURFACE BY A 1007 MB LOW NEAR 41N126W. A SURFACE COLD FRONT HAS OUTRUN THE ATTENDANT UPPER LEVEL TROUGH REACHING FROM SOUTHERN CALIFORNIA NEAR 32N118W TO 27N126W. A RECENT WINDSAT SCATTEROMETER PASS INDICATED NW-N 20 KT WINDS N OF 29N BEHIND THE FRONT WITH AN AREA OF 8 TO 10 FT NW SWELL ACROSS THE REMAINDER OF THE AREA N OF 26N BEHIND FRONT. THE FRONT WILL DISSIPATE WITHIN 24 HOURS WITH 8 TO 9 FT NW SWELL LINGERING THROUGH EARLY TUE. ACTIVE CONVECTION IS PRESENT ACROSS THE TROPICS E OF 130W NEAR THE ITCZ AND A TROUGH AXIS TO THE E WITH UPPER LEVEL RIDGING BEING MAINTAINED ACROSS AND WITHIN SEVERAL DEGREES N OF THE CONVECTION AS DESCRIBED IN THE ITCZ SECTION ABOVE. THE EASTERN EXTENT OF THE ITCZ ENDS NEAR 07N112W WITH THE TROUGH AXIS OVER THE AREA E OF THERE. THE TROUGH AXIS EXTENDS FROM 09N84W TO 07N91W WHERE SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 180 NM S OF THE AXIS. THIS TROUGH CONTINUES W FROM 07N91W TO 05N100W WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WITHIN 120 NM S OF THE TROUGH OVER THAT AREA. THIS CONVECTION IS BEING FUELED BY THE MODERATE SWLY FLOW ACROSS THIS AREA AND LIGHT NORTHERLY FLOW FEEDING DOWN FROM CENTRAL AMERICA. 20 KT S TO SW WINDS 20 KT WERE OCCURRING S OF THE TROUGHING AND AREA OF ACTIVE CONVECTION BETWEEN 84W AND 100W THIS AFTERNOON AS CAPTURED BY AN EARLIER WINDSAT PASS. THESE WINDS ARE EXPECTED TO DIMINISH TO LESS THAN 20 KT IN 24 HOURS. ELSEWHERE ALOFT...AN EQUATORIAL MID TO UPPER CYCLONE WAS NOTED IN WATER VAPOR IMAGERY NEAR 01N114W WITH A MID TO UPPER TROUGH REACHING FROM THE CYCLONE TO NEAR 15N115W. THIS TROUGH SEPARATED TWO ZONES OF ANTICYCLONIC FLOW ALOFT ON EITHER SIDE OF IT. AT THE LOW LEVELS...A BROAD SURFACE RIDGE EXTENDS FROM A 1029 MB HIGH NEAR 31N149W THROUGH THE NORTHERN DISCUSSION WATERS TO NEAR 20N114W. A TIGHT PRESSURE GRADIENT NE OF THE RIDGE IS MAINTAINING NW TO N WINDS NEAR 20 KT WITH SEAS TO 8 FT WITHIN 150 NM OF THE W COAST OF THE BAJA CALIFORNIA PENINSULA. THESE WINDS WILL PERSIST THROUGH 48 HOURS INCREASING IN COVERAGE BY THE END OF THE PERIOD AS RIDGING REBUILDS BEHIND THE ABOVE MENTIONED SURFACE COLD FRONT. HIGH ENERGY CROSS EQUATORIAL SOUTHERLY SWELL WITH CURRENT PEAK WAVE PERIODS OF 20 SECONDS WILL CROSS THE EQUATOR INTO THE SW PORTION OF THE AREA TONIGHT. THIS SWELL WILL ENCOMPASS APPROXIMATELY THE SW THIRD OF THE WATERS IN 24 HOURS THEN WILL CONTINUE PROPAGATING NE OVERTAKING THE SW TWO THIRDS OF THE AREA BY 48 HOURS AS SEAS BUILD TO BETWEEN 8 AND 11 FT. BEYOND 48 HOURS...THE SWELL WILL ARRIVE AT THE COASTLINES OF MEXICO AND CENTRAL AMERICA WITH WAVE PERIODS OF 21 TO 22 SECONDS BY EARLY TUE AND THEN REACHING THE W COAST OF THE BAJA CALIFORNIA PENINSULA TUE EVENING. VERY LARGE AND DANGEROUS SURF WILL BE SEEN ALONG THE COASTS AND SHOALS OF THE REGION AS THE SWELL ARRIVES WITH OFFSHORE WAVE HEIGHTS FORECAST TO BUILD TO 8 TO 9 FT BY WED AFTERNOON. $$ LEWITSKY