000 AXPZ20 KNHC 311520 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU MAY 31 2012 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 09N84W TO 10N109W TO A 1011 MB LOW NEAR 08N116W TO 05N122W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N122W TO 00N136W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 04N TO 11N BETWEEN 83W AND 90W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 03N TO 08N BETWEEN 97W AND 112W. ...DISCUSSION... A TROUGH-RIDGE-TROUGH-RIDGE UPPER LEVEL PATTERN SPANS THE EAST PACIFIC FORECAST WATERS. A WELL-DEFINED MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED WEST OF THE REGION NEAR 23N146W...DIGGING SLOWLY SW. A JET SEGMENT IS LOCATED ACROSS THE SE SEMICIRCLE OF THIS CYCLONE...EXTENDING THROUGH 15N140W TO 30N133W THEN TURNS E-NE OVER THE DOWNSTREAM RIDGE...AND WEAKENS AS IT CROSSES THE NORTHERN BAJA CALIFORNIA PENINSULA. DOWNSTREAM...A LARGE MIDDLE TO UPPER LEVEL RIDGE COVERS THE AREA FROM 09N TO 30N BETWEEN 100W AND 126W. THE UPPER LEVEL CYCLONE IS FORECAST TO CUT OFF FROM AN ASSOCIATED TROUGH AND SHIFT WESTWARD BY FRIDAY...WHICH WILL ALLOW THE UPPER LEVEL RIDGE TO SHIFT SLOWLY W AS A RESULT OVER THE NEXT TWO DAYS. DOWNSTREAM OF THE RIDGE...A MIDDLE TO UPPER LEVEL TROUGH CONTINUES TO EXTENDS AN AXIS FROM THE CENTRAL GULF OF MEXICO NEAR 25N90W S-SW TO 17N95W TO A BASE OVER A PORTION OF THE MONSOON TROUGH NEAR 07N103W. NORTHERLY FLOW ALOFT ON THE WESTERN PERIPHERY OF THE TROUGH CONTINUES TO TRANSPORT COLD AIR ALOFT TO THE VICINITY OF THE MONSOON TROUGH...MAINTAINING A VERY UNSTABLE AND DIFFLUENT ATMOSPHERE THROUGH THE MIDDLE AND UPPER LEVELS. SOME OF THE STRONGEST CONVECTION INDICATED ON SATELLITE IMAGERY IS OCCURRING OVER THE AREA FROM 03N TO 08N BETWEEN 97W AND 112W. EAST OF THIS UPPER LEVEL TROUGHING...AN UPPER LEVEL RIDGE WAS CENTERED ON AN ANTICYCLONE OVER THE SW CARIBBEAN SEA NEAR 12N78W. AT THE SURFACE...A RIDGE COVERS THE AREA N OF 13N W OF 115W... CENTERED ON A 1027 MB HIGH NEAR 34N136W. THE PRESSURE GRADIENT BETWEEN THE HIGH AND LOW PRESSURE ACROSS CALIFORNIA AND WESTERN ARIZONA IS YIELDING FRESH TO STRONG N-NW WINDS FROM THE OFFSHORE WATERS OF NORTHERN CALIFORNIA THROUGH THE ENTIRE LENGTH OF THE BAJA PENINSULA TO 22N. A FEW SHIP OBSERVATIONS OVER THE PAST 6 HOURS CONFIRM THESE 20 TO 25 KT WINDS WITHIN 300 NM OF THE BAJA COAST: THE APL JADE (9VVD) AT 23 KT...THE CAP PALLISAR (A8OH4) AT 24 KT...AND THE ROTTERDAM EXPRESS (DMRX) AT 24 KT. NW SWELL IS PRODUCING SEAS TO 8 FT ACROSS THIS AREA. SOUTH OF THE SURFACE RIDGE...FRESH NE TRADEWINDS ARE FOUND FROM 07N TO 10N W OF 137W AND ARE FORECAST TO EXPAND NORTH AND EAST THROUGH FRIDAY. SEAS OVER THIS AREA ARE GENERALLY LESS THAN 8 FT. THE HIGH WILL BEGIN TO SHIFT SLOWLY SW AND WEAKEN SLIGHTLY THROUGH EARLY SATURDAY AND RELAX THE PRESSURE GRADIENT TO THE SOUTH...AND THE OVERALL EXTENT OF THE FRESH TRADES. LONG-PERIOD SOUTHERN HEMISPHERE SWELL WILL CROSS THE EQUATOR AND MOVE INTO THE AREA WATERS THIS AFTERNOON AND TONIGHT...RAISING SEAS TO 9 FT S OF 06N BY FRIDAY. THIS STRONG SWELL WILL AFFECT THE PACIFIC COASTS OF CENTRAL AMERICA EARLY SUNDAY INTO MONDAY WITH HIGH SURF AND WIDESPREAD DANGEROUS RIP CURRENTS. $$ HUFFMAN