000 AXPZ20 KNHC 180338 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED MAY 18 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 0200 UTC. ...ITCZ... AXIS ALONG 06N123W TO 03N140W. NO SIGNIFICANT CONVECTION. MONSOONAL TROUGH AXIS IDENTIFIED FROM 12N103W TO 06N123W. NUMEROUS MODERATE TO STRONG CONVECTION NOTED N OF 12N BETWEEN 95W AND 100W...AND ALSO FROM 05N TO 10N BETWEEN 93W AND 100W. ...DISCUSSION... DEEP LAYERED NEGATIVE TILT TROUGH ACROSS WRN N AMERICA EXTENDED SE INTO THE DESERT SW OF THE U.S. AND WITH BASE OF TROUGH TO 28N ALONG ABOUT 114W. A SHORTWAVE SWINGING THROUGH BASE OF TROUGH TODAY IS LIFTING N INTO THE CENTRAL PLAINS...BUT HAS ALLOWED BASE OF TROUGH TO MERGE ACROSS W TEXAS WITH A LINGERING MIDDLE TO UPPER LEVEL TROUGH EXTENDING W-SW ACROSS CENTRAL BAJA CALIFORNIA NEAR 27N114W TO A MID TO UPPER LEVEL CYCLONE E OF THE BIG ISLAND OF HAWAII NEAR 20N145W. MID TO UPPER CONVERGENCE AND SUBSIDENCE OCCURRING WITHIN THIS NARROW TROUGH. A BROAD UPPER RIDGE GENERALLY PREVAILS TO THE SE OF THESE FEATURES ACROSS THE REMAINDER OF THE AREA N OF 06N...WITH MEAN RIDGE AXIS CRESTING NEAR 28N ACROSS MEXICO ALONG 108W. THIS STRONG RIDGE WILL REMAIN GENERALLY IN TACT DURING THE NEXT 24 HOURS. AT LOWER LEVELS...A LARGE SURFACE RIDGE OVER THE E CENTRAL PACIFIC WAS CENTERED ON A 1023 MB HIGH NEAR 28N144W WITH RIDGE EXTENDING SE TO NEAR 20N115W. A MODEST PRESSURE GRADIENT OFF THE W COAST OF BAJA CALIFORNIA WAS PRODUCING A ZONE OF 20 KT NW TO N WINDS AND MIXED SEAS NEAR 8 FT N OF 24N E OF 116W. SE OF THE RIDGE...MONSOONAL FLOW HAS BECOME DOMINANT ACROSS ERN TROPICAL PACIFIC E 115W DURING THE PAST WEEK OR SO...WITH S TO SW SURFACE WINDS GENERALLY S OF 07N CONVERGING WITH WLY SURFACE WINDS BETWEEN 07N AND 11N. ABUNDANT TROPICAL MOISTURE CONVERGING TO THE E AND SE OF THE MONSOONAL TROUGH AND COASTAL CENTRAL AMERICA AND MEXICO E OF 100W HAS ERUPTED INTO SCATTERED TO NUMEROUS MODERATE TO DEEP CONVECTION DURING THE PAST 24 HOURS...WITH MOST ACTIVE CONVECTION RECENTLY OCCURRING FROM THE GULF OF TEHUANTEPEC BETWEEN 94W AND 100W AND S TO 07N. THIS DEEP CONVECTION HAS BEEN SHIFTING SW DURING THE PAST FEW HOURS WITH GLOBAL MODEL GUIDANCE SUGGESTING PULSING DEEP CONVECTION TO PERSIST ACROSS THIS GENERAL AREA FOR THE NEXT 24 HOURS. RECENT GFS MODEL RUNS HAVE SUGGESTED THE DEVELOPMENT OF SURFACE LOW ACROSS SW PORTIONS OF THIS REGION OF ACTIVE CONVECTION...BUT PRESENTLY THIS SCENARIO IS NOT DEPICTED WITH THE OTHER GLOBAL MODELS. LARGE VERY LONG PERIOD SOUTHERN HEMI SWELL CONTINUES TO PROPAGATE ACROSS THE TROPICAL EPAC AND MOVE INTO THE SUB TROPICS N OF 20N THIS EVENING. GLOBAL WAVE MODEL GUIDANCE INDICATES THESE SLY SWELLS CROSSING 30N THIS EVENING...HOWEVER BUOY DATA AVAILABLE OFF THE SRN CALIFORNIA COAST HAVE NOT SHOWN THE FORERUNNERS OF THIS APPROACHING SWELL. THESE SWELLS WILL CONTRIBUTE TO WAVE HEIGHTS OF 8 TO 11 FT PREVAILING ACROSS THE TROPICAL EPAC S OF 20N AND E OF 130W THROUGH THE NEXT 36 HOURS BEFORE DIMINISHING...AND STRONGLY IMPACT THE PACIFIC COASTAL ZONES OF CENTRAL AMERICA AND MEXICO. $$ STRIPLING