000 AXPZ20 KNHC 210920 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT JUN 21 2014 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... A 1007 MB NEARLY STATIONARY SURFACE LOW IS EMBEDDED IN THE MONSOON TROUGH ANALYZED NEAR 10.5N110.5W...OR ABOUT 725 MILES S- SW OF MANZANILLO MEXICO. AN ATTENDANT TROUGH EXTENDS FROM THE LOW TO THE NE TO 18N108W. AN UPPER ANTICYCLONE IS CENTERED NEAR 08N108W WITH AN UPPER RIDGE EXTENDING TO THE NE TO SW MEXICO. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WITHIN 60-90 NM OF THE LOW CENTER...AND ALSO FROM 11N TO 14N BETWEEN 109W AND 111W ALONG THE TROUGH AXIS. CYCLONIC 15-20 KT WINDS ARE OBSERVED WITHIN 180- 240 NM OVER THE SE SEMICIRCLE WITH SEAS OF 5-8 FT. THE LOW IS EXPECTED TO MOVE NORTHWARD TO NEAR 14.5N108W BY 24 HOURS...AND TO NEAR 16N109W BY 48 HOURS. THIS LOW HAS A MEDIUM CHANCE OF TROPICAL CYCLONE FORMATION DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... AN ILL-DEFINED TROPICAL WAVE IS ANALYZED TO THE N OF 12N ALONG 96W MOVING W AT 5-10 KT. AN UPPER LEVEL RIDGE IS TO THE W OF THE WAVE EXTENDING FROM 08N108W TO 17N100W WITH UPPER LEVEL NW-N FLOW ACROSS THE TROPICAL WAVE WHICH IS ADVECTING DRY UPPER AIR SOUTHWARD SUPPRESSING CONVECTION NEAR THE WAVE AXIS. A RECENT ASCAT SCATTEROMETER PASS DID NOT SHOW MUCH OF AN INDICATION OF THE WAVE AT THE SURFACE WHILE TOTAL PRECIPITABLE WATER SATELLITE IMAGERY DID STILL SHOW EVIDENCE OF THE WAVE AXIS. THE TROPICAL WAVE IS FORECAST TO BECOME EVEN LESS DEFINED DURING THE NEXT 24 HOURS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM LOW PRES NEAR 08N77W TO 08N90W TO 12N104W TO LOW PRES NEAR 10.5N110.5W TO 08N117W TO LOW PRES NEAR 11N128W TO 08N132W. THE ITCZ AXIS EXTENDS FROM 08N132W TO BEYOND 07N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 210 NM IN THE W SEMICIRCLE OF THE LOW NEAR 08N77W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 180 NM W OF A LINE FROM 12N102W TO 06N106W...AND ALSO WITHIN 60-120 NM EITHER SIDE OF THE AXIS BETWEEN 112W AND 119W. IN ADDITION...SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS OCCURRING WITHIN 75 NM OF THE COAST OF MEXICO BETWEEN 93W AND 96W...AND ALSO BETWEEN 97W AND 103W UNDERNEATH AN UPPER LEVEL RIDGE AXIS. ...DISCUSSION... A SURFACE RIDGE EXTENDS FROM 1027 MB HIGH PRES WELL N OF THE DISCUSSION AREA NEAR 38N134W TO THE S-SE THROUGH 32N132W WITH A TERMINUS NEAR 17N112W. MODERATE ANTICYCLONIC WINDS AND 4-7 FT SEAS DOMINATE THE WATERS UNDERNEATH THE RIDGE N OF 15N W OF 110W. LITTLE CHANGE IN THE POSITION OF THE RIDGE AXIS AND THE CORRESPONDING MARINE CONDITIONS IS ANTICIPATED THROUGH THE NEXT 48 HOURS. A 1011 MB SURFACE LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR 11N128W. NO SIGNIFICANT CONVECTION IS NOTED WITH THE LOW AS AN EXPANSIVE AND DOMINATE UPPER LEVEL ANTICYCLONE NEAR 22N130W IS ADVECTING VERY DRY AND STABLE AIR FROM NE-SW ACROSS THE AREA WHERE THE LOW IS. ASSOCIATED WINDS ARE MODERATE TO FRESH WITH 6- 8 FT SEAS. THE LOW IS FORECAST TO WEAKEN AS IT REACHES 09N135W BY 48 HOURS AND MAY DEGENERATE INTO AN OPEN TROUGH BY THEN. LONG PERIOD NW AND S-SW SWELL WITH COMBINED SEAS OF 8-9 FT COVERS THE WATERS S OF A LINE FROM 03.4S92W TO 03N110W TO 03.4N120W. THIS AREA OF MIXED SWELL IS FORECAST TO DECAY TO LESS THAN 8 FT BY THIS AFTERNOON. SW MONSOONAL FLOW IS FORECAST TO INCREASE TO FRESH LEVELS NEAR A WEAK LOW EXPECTED TO FORM BY 48 HOURS NEAR 09N117W. THIS WILL BUILDS SEAS UP TO 8 FT IN THE SE PORTION OF THE LOW. $$ LEWITSKY