000 AXPZ20 KNHC 221551 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT JUN 22 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 1415 UTC. ...SPECIAL FEATURES... A 1007 MB SURFACE LOW NEAR 12N103W IS ACCOMPANIED BY NUMEROUS MODERATE TO STRONG CONVECTION WITHIN 90 NM SW SEMICIRCLE AS WELL AS SCATTERED MODERATE CONVECTION WITHIN 45 NM NE SEMICIRCLE AND ELSEWHERE WITHIN 210 NM SW SEMICIRCLE. A 1009 MB SECOND SURFACE LOW LIES TO ITS W NEAR 14N115W...WITH NUMEROUS MODERATE TO STRONG CONVECTION FOUND WITHIN 15 NM NE SEMICIRCLE AND WITHIN 45 NM SW SEMICIRCLE AS WELL AS SCATTERED MODERATE CONVECTION FOUND WITHIN ELSEWHERE 120 NM NW SEMICIRCLE. THE CURRENT FORECAST CALLS FOR CONTINUED DEVELOPMENT...POSSIBLY TROPICAL CYCLONE DEVELOPMENT...OF THE EASTERNMOST LOW PRES SYSTEM. THE WESTERNMOST LOW IS EXPECTED TO DEVELOP FURTHER THROUGH APPROXIMATELY 24 HOURS...WITH POSSIBLE TROPICAL CYCLONE FORMATION DURING THAT WINDOW. THIS LOW IS THEN FORECAST TO GRADUALLY BECOME ENGULFED IN THE BROADER CIRCULATION AROUND THE LOW FURTHER E. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM THE COAST OF COSTA RICA NEAR 10N86W TO 13N100W TO 1007 MB LOW PRES NEAR 12N103W TO 1009 MB LOW PRES NEAR 14N115W TO 13N118W. THE ITCZ AXIS WAS ANALYZED FROM 13N118W TO 09N126W TO 08N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 120 NM N OF THE AXIS BETWEEN 88W AND 95W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS FOUND ON THE E EDGE OF THE MONSOON TROUGH FROM 03N TO 09N E OF 86W TO THE COAST OF COLOMBIA...PANAMA...AND COSTA RICA. ...DISCUSSION... TWO ANTICYCLONES ALOFT RESIDE OVER CENTRAL WATERS. THE NORTHERNMOST ANTICYCLONE IS NEAR 23N120W AND EXTENDS A RIDGE AXIS FROM 16N140W TO 23N130W THROUGH THE ANTICYCLONE AND THE GULF OF CALIFORNIA INTO CENTRAL TEXAS. THE SECOND ANTICYCLONE LIES NEAR 14N111W AND EXTENDS A NORTHERN RIDGE AXIS THROUGH ACAPULCO AND A SOUTHERN RIDGE AXIS FROM THE ANTICYCLONE TO 10N106W SOUTHWARD TO 00N106W. WHILE WATER VAPOR IMAGERY SHOWS DRY AIR AND IMPLIED SUBSIDENCE DOMINATE THE AREA NEAR THE NORTHERNMOST ANTICYCLONE AND ITS RIDGE...UPPER LEVEL DIVERGENCE BETWEEN NORTHERLY WINDS ALOFT SE OF THE ANTICYCLONE AND EASTERLY FLOW S AND SE OF THE ANTICYCLONE IS ENHANCING CONVECTION NEAR THE EASTERNMOST SURFACE LOW PRES SYSTEM NOTED IN THE SPECIAL FEATURES SECTION. THIS ANTICYCLONE SHOULD REMAIN STATIONARY AND BUILD OVER THE NEXT 24 HOURS OR SO. THIS SHOULD HELP THE DEVELOPMENT OF THE EASTERNMOST SURFACE LOW WHICH LIES WITHIN AN AREA OF PLENTIFUL LOW- TO MID-LEVEL MOISTURE AS SEEN BY PRECIPITABLE WATER IMAGERY. ELSEWHERE AT THE SURFACE...A 1026 MB SUBTROPICAL HIGH RESIDES NEAR 32N142W. THIS HIGH IS FORECAST TO SHIFT WESTWARD AND WEAKEN AS A COLD FRONT WELL N OF THE AREA APPROACHES IT FROM THE N. FRESH TRADE WINDS WERE NOTED BY THE 0905 UTC OSCAT AND 0713 UTC ASCAT PASSES OVER WATERS S OF 137W FROM 08N-16N. SEAS TO 8 FT LIE WITHIN THIS AREA. THE REGION OF STRONGEST TRADES WILL SHIFT W OVER THE NEXT DAY OR SO WITH THE SURFACE HIGH...AND SEAS ARE FORECAST TO SUBSIDE. SE AND SW SWELL RESULTING IN COMBINED SEAS TO 8 FT WILL CROSS THE EQUATOR BETWEEN 120W-130W TONIGHT. THE LEADING EDGE OF THIS SWELL WILL PROPAGATE TO 11N BETWEEN 100W-135W ON MON MORNING. BY THEN...COMBINED SEAS OVER 8 FT ASSOCIATED WITH THIS SWELL WILL MERGE WITH THE MIXED SWELL ASSOCIATED WITH THE TWO SURFACE LOWS DESCRIBED IN THE SPECIAL FEATURES SECTION. BY MON EVENING...THE LEADING EDGE OF THE SWELL WITH PERIODS BETWEEN 19-21 SECTIONS IS EXPECTED TO REACH THE COAST OF CENTRAL AMERICA AS WELL AS THE GULF OF CALIFORNIA AND THE COAST OF BAJA CALIFORNIA SUR...WITH SEAS OFFSHORE THERE PRIMARILY IN THE 3-5 FT RANGE. $$ SCHAUER