000 AXPZ20 KNHC 180242 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI OCT 18 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0200 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH FROM 11N86W TO 1011 MB LOW PRES NEAR 10N92W TO 10.5N105W TO A SECOND 1011 MB LOW PRES NEAR 10N109.5W TO 09N125W TO 10N140W. SCATTERED MODERATE CONVECTION IS NOTED FROM 07N TO 10N BETWEEN 90W AND 96W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS JUST E OF SECOND LOW AND COVERS FROM 8.5N TO 10N BETWEEN 107W AND 109W. ...DISCUSSION... ALOFT...A LARGE ANTICYCLONE CENTERED OVER THE SE GULF OF MEXICO EXTENDS A RIDGE ACROSS SOUTHERN MEXICO INTO THE PACIFIC WATERS TO NEAR 14N109W. A MID TO UPPER-LEVEL TROUGH EXTENDS SW FROM NORTHERN BAJA CALIFORNIA TO NEAR 20N126W WHILE A RIDGE DOMINATES THE NW PART OF THE FORECAST REGION. POST-TROPICAL REMNANT LOW PRISCILLA HAS A WELL-DEFINED SWIRL OF LOW CLOUDS CENTERED NEAR 19N124W...AND CONTINUES TO MOVE OVER OVER COOL WATER IN A HIGH SHEAR ENVIRONMENT ASSOCIATED WITH THE AFOREMENTIONED TROUGH. THE SYSTEM APPEARS TO BE RAPIDLY WEAKENING AND WILL BECOME A TROUGH BY LATE FRI. THE TROUGH WILL MOVE WESTWARD REACHING 130W BY SAT. SCATTEROMETER PASSES BETWEEN 1700 AND 2000 UTC SHOWED WINDS OF 20 KT ON THE NW QUADRANT OF THE REMNANT LOW WITH SEAS TO 7 FT. RELATIVELY BENIGN MARINE CONDITIONS CHARACTERIZE THE FORECAST REGION WITH WIDESPREAD GENTLE TO MODERATE WINDS AND 4-6 FT SEAS. A SMALL AREA OF TRADE WINDS TO 15-20 KT AND SEAS TO 7 FT IS NOTED ALONG THE SOUTHERN PERIPHERY OF A RIDGE THAT DOMINATES MOST OF THE N WATERS AND BAJA CALIFORNIA. WEAK LOW PRES AREA EMBEDDED IN THE MONSOON TROUGH IS CENTERED NEAR 10N109.5 WITH A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION JUST TO THE EAST OF CENTER. THE MOST RECENT OSCAT PASS SHOWED THE CYCLONIC CIRCULATION ASSOCIATED WITH THIS LOW AND WINDS OF 10-15 KT WITH A FEW 20 KT WIND BARBS TO THE NE OF THE CENTER. THE LOW IS EXPECTED TO MOVE W WITH LITTLE CHANGE IN INTENSITY THROUGH SAT. AN AREA OF LOW PRES PREVIOUSLY ASSOCIATED WITH A TROPICAL WAVE THAT MOVED THROUGH CENTRAL AMERICA THE PAST DAY OR SO IS CENTERED NEAR 10N92W. A BAND-LIKE FEATURE OF SCATTERED MODERATE CONVECTION IS NOTED MAINLY TO THE SOUTH AND SW OF CENTER. UPPER- LEVEL WINDS ARE EXPECTED TO BECOME CONDUCIVE FOR SOME SLOW DEVELOPMENT BY EARLY NEXT WEEK. MONSOONAL SOUTHERLY FLOW IS FORECAST TO INCREASE TO MODERATE TO FRESH AS IT MOVES SLOWLY WESTWARD TO WEST-NORTHWESTWARD WHICH WILL BUILD SEAS TO 6-7 FT. LOOKING AHEAD...VERY LONG PERIOD SWELL FROM THE NW WILL IMPACT THE NW WATERS SUN AND MON. WAVE MODEL GUIDANCE SHOWS LEADING EDGE OF SWELL TRAIN WITH 22-23 SEC PERIOD...WHICH WILL PRODUCE UNUSUALLY LARGE SURF HEIGHTS AS IT REACHES SHALLOW WATER ALONG THE PACIFIC COAST NEXT WEEK. THIS POWERFUL SWELL EVENT WILL BE ASSOCIATED WITH A STRONG LOW PRES SYSTEM LOCATED W OF AREA. $$ GR