000 AXPZ20 KNHC 290303 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED SEP 29 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0215 UTC. ...ITCZ... AXIS ANALYZED ALONG 11N109W TO LOW PRES 11N120W TO LOW PRES 13N134W TO 11N140W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 120 NM S OF AXIS BETWEEN 131W AND 135W...AND WITHIN 150 NM EITHER SIDE OF AXIS W OF 135W. ...DISCUSSION... W OF 125W... MID/UPPER LEVEL ANTICYLONE NEAR 19N136W WAS DRIFTING NW AHEAD OF A VERY SHARP AND RATHER VIGOROUS SHORTWAVE TROUGH APPROACHING THE FAR NW CORNER OF THE REGION. THE COLD FRONT ASSOCIATED WITH THE SHORT WAVE WAS NEARING 30N141W. SLY UPPER LEVEL FLOW WAS INCREASING AHEAD OF THE TROUGH IN A VERY PRONOUNCED JET STREAM WITH WINDS OF 45-70 KT. SATELLITE WATER VAPOR IMAGERY DEPICTED MODERATE SUBSIDENCE OVER MOST OF THIS PORTION OF THE REGION RESULTING IN STABLE ENVIRONMENTAL CONDITIONS WITH SCATTERED TO BROKEN STRATOCUMULUS CLOUDS NOTED N OF 19N...AND LIMITED MOISTURE IN THE TROPICAL ZONE. DEEP CONVECTION OCCURRING ALONG THE ITCZ WAS MOVING INTO A ZONE OF DIFFLUENT FLOW ALOFT AND INDUCING FURTHER DIVERGENCE ALOFT W OF 135W. E OF 125W... A MID/UPPER LEVEL CYCLONIC CIRCULATION WAS OVER THE FAR NE PART NEAR 30N119W MOVING W AT 15 KT. A TROUGH EXTENDS SW FROM THE CIRCULATION TO A COL REGION AT 21N130W...WHILE A SECOND SHARP AND NARROW TROUGH AXIS EXTENDED SE ACROSS EXTREME NRN MEXICO AND INTO THE NW GULF OF MEXICO...WHERE IT LINKED TO THE SW FLANKS OF AN DEEP UPPER TROUGH AFFECTING THE E HALF OF THE U.S. AND MOST OF THE GULF OF MEXICO. THE MID/UPPER LOW ACROSS NE PORTIONS OF THE AREA...AND ITS ASSOCIATED TROUGH WERE TRAPPED IN BETWEEN TWO ANTICYCLONES...THE FORMER NEAR 19N136W...AND A MUCH LARGER BLOCKING ANTICYCLONE ANCHORED OVER THE WESTERN U.S. A TROPICAL UPPER RIDGE AXIS EXTENDED SOMEWHAT E TO W ACROSS SOUTHERN PORTIONS OF THE AREA FROM AN ANTICYCLONE NEAR 20N109W. THE ANTICYCLONE WAS OVER AND JUST TO THE N OF A SURFACE LOW NEAR 18N107W...AND WAS PROVIDING ANTICYCLONIC OUTFLOW TO SUPPORT SCATTERED CONVECTION THAT HAD DEVELOPED ASSOCIATED WITH THE LOW. THIS LOW WAS SITUATED ON THE FAR WESTERN PERIPHERY OF AN ELONGATED MONSOONAL GYRE THAT HAS PERSISTED ACROSS THE FAR EPAC...SRN MEXICO...AND CENTRAL AMERICA THE PAST WEEK OR SO...AND THAT HAS EXTENDED INTO THE W CARIBBEAN IN RECENT DAYS AND PROVIDED THE ENVIRONMENT TO SPAWN T.D. 16. THIS LOW IS FORECAST TO REMAIN EMBEDDED WITHIN AN ELONGATED NODE OF THIS CYCLONIC GYRE AND IS NOT EXPECTED TO BECOME MUCH BETTER ORGANIZED...DESPITE ITS LOCATION NEAR THE UPPER HIGH...AS IT IS JUST FAR ENOUGH TO THE S OF THE UPPER HIGH TO BE FEELING NE WIND SHEAR. THE LIKELIHOOD IS LOW FOR IT TO BECOME A TROPICAL CYCLONE OVER THE NEXT 48 HOURS. THIS BROAD CYCLONIC GYRE CONTINUES TO DOMINATE A LARGE PORTION OF THE FORECAST AREA...NAMELY S OF 18N AND E OF 115W...WITH ANTICYCLONIC CROSS HEMISPHERIC SE TO S FLOW...BECOMING CONFLUENT SW TO W FLOW BETWEEN 08N AND 13N. AFTERNOON ASCAT PASSES DEPICTED 20 KT SWLY FLOW ACROSS MUCH OF THIS CONFLUENT AREA...WITH WWIII OUTPUT FORECASTING 8 TO 9 FT SEAS. A CYCLONIC CIRCULATION WAS NOTED NEAR NEAR 14N93W... WHERE A 1003 MB SURFACE LOW IS ESTIMATED. A 1530 UTC ASCAT PASS SHOWED W TO SW WINDS OF 20 TO 30 KT S THROUGH SW OF THIS LOW EXTENDING W TO 98W...AND NLY WINDS OF 20-30 KT FLOWING FROM THE GULF OF MEXICO THROUGH THE ISTHMUS OF TEHUANTEPEC AND EXITING ON THE PACIFIC SIDE THROUGH THE GULF NEAR 20 KT. SEAS IN THE STRONG W TO SW FLOW WERE FORECAST BY WWIII AT 8 TO 12 FT...WHILE AT 0000 UTC SHIP "DGSE" REPORTED W WINDS AT 34 KT AND 14 FT SEAS NEAR 13.3N93.8W. SCATTERED TO NUMEROUS CONVECTION WAS OCCURRING IN THIS W TO SW FLOW S THROUGH SW OF THE LOW. THIS LOW MAY BE A PORTION OF THE MID LEVEL REMNANTS OF MATTHEW. THE LOW IS FORECAST BY GLOBAL MODELS TO MOVE E-SE OVER THE NEXT FEW DAYS AND THEN INLAND OVER GUATEMALA AND EL SALVADOR AND EMERGE IN THE W CARIB AS IT REMAINS EMBEDDED IN THE CYCLONIC GYRE. ELSEWHERE...15-17 SEC LONG PERIOD SWELL CONTINUES TO PUSH SE FROM THE N CENTRAL PACIFIC IN TO THE DISCUSSION AREA. ALTIMETRY DATA SHOWS SEAS BEGINNING TO SUBSIDE FROM A MAX OF 13 FT OVER NW WATERS FROM THIS SWELL TRAIN. THIS INITIAL SWELL TRAIN WILL CONTINUE TO SPREAD SE ACROSS NW HALF OF THE BASIN AND GRADUALLY SUBSIDE... WHILE A SECOND SURGE OF NW SWELL WILL REACH FAR NW WATERS TUE AND BRING THE SEAS BACK TO THE 10 TO 13 FT RANGE TONIGHT. $$ STRIPLING