000 AXPZ20 KNHC 210339 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU APR 20 2011 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 0315 UTC. ...ITCZ... AXIS IS CENTERED ALONG 8N83W 6N94W 5N104W 4N104W 7N115W 4N130W 5N140W. SCATTERED MODERATE ISOLATED/STRONG CONVECTION EXISTS FROM 8N-11N BETWEEN 113W-119W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM N OF THE AXIS BETWEEN 90W-93W...AND WITHIN 60 NM S OF AXIS BETWEEN 128W-133W. ...DISCUSSION... ZONAL FLOW ALOFT GENERALLY DOMINATES THE DISCUSSION AREA N OF ABOUT 20N AS LARGE TROUGHS CONTINUE TO BYPASS THE REGION AS THEY MIGRATE FROM W TO E JUST TO THE N OF THE AREA. ONE NOTABLE LONGWAVE TROUGH IS ALONG 129W...AND QUICKLY MOVING EWD TOWARDS THE U.S. W COAST. THIS TROUGH EXTENDED SW TO NW OF THE HAWAIIAN ISLAND CHAIN. S OF 20N...BROAD RIDGING CONTINUED ACROSS AND TO THE N OF ACTIVE ITCZ CONVECTION OCCURRING BETWEEN 88W AND 138W. THIS CONVECTION IS EXPECTED TO REMAIN ACTIVE DURING THE NEXT 24 TO 48 HOURS NEAR THE ITCZ AS SST'S REMAIN WARM AND LOW LEVEL FORCING PERSISTS PARTICULARLY W OF 115W. AT LOWER LEVELS...HIGH PRES AND ANTICYCLONIC FLOW DOMINATES THE AREA N OF 10N AND W OF 105W WITH A RIDGE INTO THE REGION THROUGH 30N140W SE TO 21N121W TO NEAR 14N107W. THE RIDGE SHOULD WEAKEN WHILE SHIFTING SOME TO THE S AS A COLD FRONT PASSES JUST TO THE N OF THE AREA OVER THE NEXT 24-36 HOURS. CURRENTLY...THERE IS AN AREA OF NE 20 KT TRADES ON THE SOUTHERN PERIPHERY OF THE RIDGE FROM 4N TO 14N W OF 135W AND FROM 7N TO 13N BETWEEN 124W-135W AS WAS SUGGESTED BY A HIGH RESOLUTION ASCAT PASS FROM YESTERDAY. THIS AREA OF TRADES WILL CHANGE ONLY LITTLE DURING THE NEXT 48 HOURS AS NEW HIGH PRES BUILDS FROM W TO E OVER THE NW PORTION OF THE AREA. A TIGHT PRES OVER THE NE PORTION OF THE AREA BETWEEN THE RIDGE AND LOWER PRES OVER WESTERN U.S. AND NW MEXICO IS RESULTING IN 20 NW WINDS WITHIN 120 NM OF THE BAJA CALIFORNIA COAST N OF 24N. THESE WINDS ARE FORECAST TO INCREASE TO 20-25 KT OVERNIGHT AND INTO THU MORNING...AND CONTINUE THROUGH EARLY FRI EVENING AS THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES OVER MEXICO TIGHTENS. THREE RATHER WEAK PERTURBATIONS ARE SUGGESTED IN SATELLITE IMAGERY ALONG THE ITCZ. A TROUGH IS ALONG 137W/138W FROM 4N TO 9N ...ANOTHER FROM 10N116W TO 6N121W...AND ANOTHER ONE FROM 11N93W TO A WEAK LOW OF 1010 MB NEAR 8N95W. THE THIRD TROUGH WITH ASSOCIATED LOW PRES IS PRODUCING CONVECTION N OF THE ITCZ AS DESCRIBED ABOVE. THIS FEATURE IS FORECAST TO MOVE WNW TO NEAR 7N98W BY THU EVENING. A LOW TO MID LEVEL DEFORMATION ZONE REMAINS TO THE NW OF THE THIRD TROUGH MENTIONED ABOVE. IT IS COMBINING WITH THE MID LEVEL TROUGH EXTENDING W INTO CENTRAL MEXICO TO ADVECT A PLUME OF TROPICAL MOISTURE FROM NEAR 11N103W NORTHEASTWARD TO ACROSS THE GULF OF TEHUANTEPEC AND INTO SE MEXICO AND GUATEMALA. WIDELY SCATTERED TO SCATTERED SHOWERS AND TSTMS WITHIN 60 NM SE OF THE MOISTURE PLUME WILL CONTINUE TO TRAIN NORTHEASTWARD TOWARDS THE GULF OF TEHUANTEPEC...AND INTO INLAND MEXICO. THIS MOISTURE COMBINED WITH HEATING DURING THE DAY ON THU WILL LIKELY ALLOW FOR ACTIVE CONVECTION TO CONTINUE INLAND OVER SE MEXICO AND NORTHERN GUATEMALA THROUGH...WITH POSSIBLE HEAVY RAINFALL THROUGH THE NEXT COUPLE OF DAYS. VERY LONG PERIOD 19-21 SECOND CROSS-EQUATORIAL SW SWELL WILL PROPAGATE NE ACROSS THE EQUATORIAL WATERS DURING THE REMAINDER OF THE WEEK REACHING COASTAL AREAS FROM COLOMBIA TO BAJA CALIFORNIA THU MORNING...AND POSSIBLY TO THE SOUTHERN CALIFORNIA AREA BY FRI MORNING. WHILE DEEP WATER WAVE HEIGHTS WILL BE LESS THAN 8 FT AS THE SWELL PROPAGATES AWAY FROM THE EQUATOR...THIS HIGH ENERGY SWELL IS EXPECTED TO SLOWLY BUILD TO 3 TO 6 FT BY FRI AND WILL CREATE VERY HAZARDOUS SURF CONDITIONS ALONG EXPOSED COASTAL LOCATIONS INCLUDING SIGNIFICANT RIP CURRENT HAZARDS LATE THU THROUGH SAT. $$ AGUIRRE