000 AXPZ20 KNHC 281530 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SUN APR 28 2013 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 05N77W TO 09N84W TO 08N103W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N103W TO 08N112W TO 09N123W TO 02N140W. ISOLATED MODERATE CONVECTION IS FROM 03N TO 09N BETWEEN 77W AND 88W...AND FROM 06N TO 08N BETWEEN 95W AND 99W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 10N BETWEEN 110W AND 116W...AND FROM 08N TO 12N BETWEEN 121W AND 126W. ...DISCUSSION... UPPER LEVEL SOUTHWESTERLY FLOW DOMINATES MOST OF THE DISCUSSION AREA N OF 10N W OF 100W...BETWEEN AN ANTICYCLONIC CIRCULATION CENTERED NEAR 11N98W AND AN UPPER LEVEL LOW AND ASSOCIATED TROUGHING EXTENDING FROM 33N133W TO 26N140W TO A BASE NEAR 17N150W. THE UPPER LEVEL ANTICYCLONE ANCHORS A RIDGE S OF 20N THAT SPANS BETWEEN 90W AND 110W. WATER VAPOR IMAGERY INDICATES MODERATE TO STRONG DRY AIR AND SUBSIDENCE WITHIN THE UPPER LEVEL TROUGH MEANDERING ACROSS N AND NW PORTIONS OF THE AREA. THE MOST SIGNIFICANT CONVECTION REMAINS FOCUSED NEAR AND TO THE EAST OF A SURFACE TROUGH ANALYZED ALONG 125W FROM 07N TO 13N....WHILE MID- LEVEL CYCLONIC TURNING IS NOTED IN SATELLITE IMAGERY OCCURRING TO THE EAST OF THE SURFACE TROUGH CENTERED NEAR 09N115W... RECENT GFS ANALYSIS INDICATES THAT THE MID-LEVEL PERTURBATION SEEN IN SATELLITE IMAGERY ALONG 115W CONTINUES TO LOCATE IN AN AREA OF MAXIMUM DIFFLUENCE THEREFORE SUSTAINING CONVECTION WITH OPTIMUM OUTFLOW ALOFT. GLOBAL MODELS FORECAST THIS MID-LEVEL PERTURBATION TO CONTINUE TO SHIFT W AND WEAKEN DURING THE NEXT 24 HOURS...WITH THE ASSOCIATED CONVECTION GRADUALLY WANING AS WELL. AT THE SURFACE...A 1031 MB HIGH IS CENTERED N-NW OF THE AREA NEAR 39N137W AND EXTENDS A RIDGE SE TO NEAR 17N110W...AND S ACROSS SW PORTIONS OF THE AREA. OVERNIGHT ASCAT PASSES SHOWED FRESH NE TRADES 20-25 KT OCCURRING WEST AND NORTH OF THE SURFACE TROUGH TO 130W...AND GENERALLY FROM 08N TO 14N W OF 130W. SEAS IN THIS ZONE ARE RUNNING 7 TO 9 FT IN MERGING NE WIND SWELL AND SOUTHERN HEMISPHERE SW SWELL. THE WAVE MENTIONED ABOVE AND SURFACE TROUGH WILL BOTH MOVE W AND WEAKEN DURING THE NEXT COUPLE OF DAYS...WITH THE ZONE OF FRESH TRADES GRADUALLY DECREASING. FOR THE REMAINDER OF THE EASTERN PACIFIC BASIN E OF 110W... RELATIVELY TRANQUIL CONDITIONS ARE NOTED IN OBSERVATIONAL DATA...RECENT SCATTEROMETER PASSES...AND LATEST GLOBAL MODEL DATA. OF NOTE...SW SWELL FROM A SOUTHERN HEMISPHERE LOW PRESSURE SYSTEM WILL CONTINUE SPREADING NORTHEASTWARD AND REACH THE MEXICAN AND CENTRAL AMERICAN COAST BY EARLY MONDAY WITH WAVE PERIODS IN THE RANGE OF 15 TO 17 SECONDS. $$ HUFFMAN