000 AXPZ20 KNHC 190918 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI SEP 19 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 92W N OF 8N MOVING W ABOUT 10 KT. WHILE LOW TO MID LEVEL CYCLONIC TURNING IS EVIDENT ABOUT THE WAVE AXIS...IT IS BECOMING EMBEDDED WITHIN A LARGER SCALE CYCLONIC GYRE TO ITS W...SSW OF THE GULF OF TEHUANTEPEC. MORE ABOUT THIS IN THE DISCUSSION SECTION BELOW. TROPICAL WAVE IS ALONG 102W FROM 6N TO 16N MOVING W ABOUT 10 KT. LIKE THE WAVE TO ITS E...THIS FEATURE IS ALSO EMBEDDED IN THE LARGER SCALE CYCLONIC GYRE. THE COMBINED VORTICITY OF THESE WAVES...AND OTHER SOURCES...MAY LEAD TO GRADUAL DEVELOPMENT OVER THE NEXT COUPLE OF DAYS. TROPICAL WAVE IS ALONG 119W/120W FROM 6N TO 16N MOVING W 5-10 KT. A WEAK LOW-LEVEL SWIRL IS LOCATED ALONG THE WAVE AXIS NEAR 11N. CONVECTION IS ISOLATED AT MOST WITHIN 150 NM OF THE WAVE AXIS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N78W 13N88W 11N96W 10N110W 10N120W 9N140W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 2N-7N E OF 83W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 300 NM S OF AXIS BETWEEN 88W-108W. SCATTERED MODERATE CONVECTION IS FROM 6N-8N BETWEEN 112W-116W. ...DISCUSSION... E OF 110W... A QSCAT PASS AROUND 00Z REVEALED A VERY BROAD AND HIGHLY STRETCHED E-W SFC AREA OF LOW PRES ALONG 11N S OF THE GULF OF TEHUANTEPEC. AS ADDRESSED ABOVE...A COUPLE OF TROPICAL WAVES ARE EMBEDDED WITHIN THIS SLOW MOVING BROAD LOW. WHILE THERE IS A LARGE AREA OF SCATTERED MODERATE CONVECTION...N OF 9N BETWEEN 91W-101W AND FROM 5N-8N BETWEEN 101W-108W...IT HAS LITTLE ORGANIZATION. SWIFT UPPER LEVEL ELY FLOW IS LIKELY LIMITING DEVELOPMENT AT THE MOMENT. THE UPPER ENVIRONMENT IS EXPECTED TO IMPROVE OVER THE NEXT COUPLE OF DAYS AND GRADUAL DEVELOPMENT IS POSSIBLE. ELSEWHERE...A FAIR AMOUNT OF MOISTURE IS IN PLACE OVER THE TROPICS BUT CONVECTION IS CONFINED TO THE ITCZ. THE AFOREMENTIONED 00Z QSCAT PASS SHOWED 20-30 KT N WINDS IN THE GULF OF TEHUANTEPEC. HOWEVER...WINDS ARE LIKELY WEAKENING AS ASSOCIATED TROUGHING IS BECOMING LESS DEFINED OVER THE SW GULF OF MEXICO. GFS/NAM GUIDANCE SUGGESTS THAT WINDS SHOULD DIMINISH BELOW 20 KT IN 24-36 HOURS. S TO SW 15-20 KT WINDS AND LONG PERIOD SW SWELL IS BUILDING SEAS TO 9 FT S OF THE ITCZ FROM 4N-10N BETWEEN 90W-110W. LITTLE CHANGE IS EXPECTED IN THIS REGIME OVER THE NEXT COUPLE OF DAYS. W OF 110W... A DEEP LAYER LOW PRESSURE SYSTEM NEAR THE N CALIFORNIA COAST IS INDUCING TROUGHING TO NEAR 29N125W. WEAK MID TO UPPER TROUGHING ALSO LIES JUST W OF THE ZONE ALONG 142W. RIDGING EXISTS ELSEWHERE AND THE OVERALL CONFLUENT ZONES BETWEEN THESE FEATURES IS ENHANCING STABILITY MAINLY N OF 22N. THE LOW OFF THE NRN CA COAST DRAPES A WEAKENING STATIONARY FRONT ACROSS THE NW CORNER OF THE ZONE. WHILE THIS FEATURE IS WEAKENING THE TRADE WIND FLOW...NW SWELL IS ELEVATING SEAS TO 8 FT ACROSS THE FAR NW WATERS AS CONFIRMED BY A RECENT ALTIMETER PASS. THE PRES GRADIENT IS TIGHTEST NEAR THE S CALIFORNIA COAST...PRODUCING 20 KT N TO NW WINDS JUST N OF 30N. $$ CANGIALOSI