000 AXPZ20 KNHC 240915 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC WED SEP 24 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0845 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 89W N OF 05N MOVING W 10-15 KT. THIS WAVE HAS BEEN CHALLENGING TO TRACK FOR DAYS AND ITS CURRENT POSITION IS MAINLY BASED ON FORWARD EXTRAPOLATION. SCATTERED SHOWERS AND TSTMS OVER GUATEMALA...HONDURAS AND NICARAGUA MAY BE PARTIALLY ASSOCIATED WITH THIS ILL-DEFINED FEATURE. TROPICAL WAVE IS ALONG 97W N OF 08N MOVING W 10 KT. SHORTWAVE IR IMAGES REVEAL FAIRLY WELL DEFINED MID-LEVEL CYCLONIC TURNING ABOUT THE WAVE AXIS FOCUSED NEAR 13N. HOWEVER...SHIP REPORTS IN THIS VICINITY LIKELY SUGGEST THAT THIS CIRCULATION IS OFF THE SFC. DEEP CONVECTION HAS INCREASED OVER THE PAST SEVERAL HOURS N OF 13N BETWEEN 93W-101W. GLOBAL MODELS DO SUGGEST SFC LOW PRES DEVELOPMENT BUT IT WILL LIKELY BE LIMITED SOME DUE TO SWIFT UPPER ELY WINDS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 09N84W 13N95W 10N110W 09N115W 08N140W. SCATTERED MODERATE CONVECTION IS FROM 10N TO 12N BETWEEN 96W AND 100W. ...DISCUSSION... E OF 115W... A SFC LOW IS TRACKING W AT 10 KT CENTERED ABOUT 400 NM S OF THE SRN TIP OF BAJA CALIFORNIA NEAR 17N110W...ANALYZED 1007 MB. AFTER GAINING SOME CONVECTION OVER ITS WRN SEMICIRCLE THROUGHOUT THE DAY TUE...IT HAS ONCE AGAIN DIMINISHED. A QSCAT PASS AROUND 01Z DEPICTED THE CIRCULATION WELL AND INDICATED WINDS TO 20 KT WITHIN 180 NM NW SEMICIRCLE AND SLIGHTLY WEAKER WINDS OVER THE SE PART OF THE LOW. THIS SYSTEM IS MOVING INTO VERY STABLE AIR SO ANY DEVELOPMENT WOULD BE SLOW TO OCCUR. A MID TO UPPER HIGH OVER SOUTHERN MEXICO CONTINUES TO PROVIDE NE/E FLOW AND CONSIDERABLE MOISTURE E OF 110W. WHILE THE ATMOSPHERE IS VERY MOIST...CONVECTION IS CONFINED TO THE TROPICAL WAVE ALONG 97W (DISCUSSED ABOVE). QSCAT DATA SHOWED 20 KT NW TO N WINDS WITHIN 120 NM OFF THE BAJA COAST N OF 25N. THESE WINDS WILL LIKELY CHANGE LITTLE OR DIMINISH SLIGHTLY OVER THE NEXT DAY OR SO. W OF 115W... THE SFC PATTERN HAS CHANGED LITTLE OVER THE PAST FEW DAYS WITH HIGH PRES CENTERED NW OF THE ZONE AND A QUASI-STATIONARY SFC LOW EMBEDDED WITHIN THE ITCZ NEAR 10N123W. THIS LOW HAS DIMINISHED TO A SWIRL OF LOW CLOUDS TONIGHT AND IS FORECAST TO OPEN INTO A TROUGH OVER THE NEXT DAY OR TWO. THE PRES GRADIENT BETWEEN THESE FEATURES CONTINUES TO SUPPORT 20 KT NE TRADES FROM 14N-20N W OF 130W. IN THE MID AND UPPER LEVELS...WIDESPREAD DRY STABLE AIR EXISTS OVER THIS ENTIRE REGION...ESPECIALLY IN THE CONFLUENT ZONE BETWEEN TROUGHING N OF 25N AND RIDGING ALONG 15N. CROSS-EQUATORIAL SLY SWELL...WITH PERIODS OF 16-18 SECONDS...HAS ELEVATED SEAS TO 8 FT S OF 08N BETWEEN 105W AND 130W. THIS SWELL TRAIN WILL CONTINUE NNE TOWARD THE COAST OF MEXICO/CENTRAL AMERICA DURING THE DAY TODAY AND GRADUALLY DIMINISH THU AND FRI. $$ CANGIALOSI