000 AXPZ20 KNHC 300334 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU SEP 30 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 0200 UTC. ...ITCZ... .AXIS ANALYZED ALONG 10N101W TO 09N108W TO LOW PRES 10N115.5W 1010 MB TO 09N119W TO LOW PRES 13N134.5W 1009 MB TO 11N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 120 NM S OF AXIS E OF 108W...AND WITHIN 180 NM OF LOW NEAR 13N134.5W. ...DISCUSSION... W OF 125W... A MID/UPPER LEVEL ANTICYLONE NEAR 23N134W WITH A NARROW RIDGE EXTENDING TO WELL N OF THE AREA WITH A CREST AT 35N129W WAS DRIFTING NW AHEAD OF A RATHER VIGOROUS SHORTWAVE TROUGH LIFTING NE THROUGH THE FAR NW CORNER OF THE AREA. AT THE SURFACE...A STATIONARY FRONT WAS JUST NW OF THE AREA DRAPED FROM 31N140W TO 24N150W...AND JUST N OF THE HAWAIIAN ISLANDS. SATELLITE WATER VAPOR IMAGERY DEPICTED MODERATE SUBSIDENCE OVER MOST OF THIS PORTION OF THE REGION RESULTING IN STABLE ENVIRONMENTAL CONDITIONS WITH BROKEN TO OVERCAST STRATOCUMULUS CLOUDS N OF 20N...AND LIMITED MOISTURE IN THE TROPICAL ZONE. DEEP CONVECTION OCCURRING ALONG THE ITCZ PERSISTED WITHIN AN UPPER LEVEL DIFFLUENT ASYMPTOTE...AND WAS INDUCING FURTHER DIVERGENCE ALOFT W OF 132W. MUCH OF THIS CONVECTION WAS BEING FORCED BY LOW LEVEL CONVERGENCE ASSOCIATED AROUND AN ELONGATED 1009 MB LOW NEAR 13N134.5W. E OF 125W... A MID/UPPER LEVEL CYCLONIC CIRCULATION WAS ALONG THE BORDER OF THE FAR NE PART OF THE AREA NEAR 31N120W MOVING SLOWLY NW. A TROUGH EXTENDED SW FROM THE CIRCULATION TO NEAR 20N130W. THIS MID/UPPER LOW WAS TRAPPED IN BETWEEN A BLOCKING RIDGE ANCHORED OVER THE CENTRAL PLAINS...AND THE SHORTWAVE TROUGH EDGING INTO THE NW CORNER OF THE AREA. AN UPPER LEVEL ANTICYCLONE WAS LOCATED NEAR 20N113W WITH A RIDGE W TO 21N127W...AND ANOTHER RIDGE EXTENDING NE TO THE CENTRAL PLAINS HIGH. THIS ANTICYCLONE REMAINED OVER AND JUST TO THE N OF A NEARLY STATIONARY SURFACE LOW NEAR 17N105.5...AND WAS CONTINUING TO PROVIDE ANTICYCLONIC OUTFLOW TO SUPPORT SCATTERED MODERATE/ISOLATED STRONG CONVECTION THAT WAS WITHIN 180 NM W OF 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 WHAT IS NOW THE REMNANTS LOW OF FORMER TROPICAL STORM NICOLE. THIS PACIFIC LOW IS FORECAST TO REMAIN RELATIVELY STATIONARY AND EMBEDDED WITHIN AN ELONGATED LOBE OF THIS CYCLONIC GYRE...AND IS NOT EXPECTED TO BECOME MUCH BETTER ORGANIZED. THE 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 E OF 120W...BECOMING CONFLUENT SW TO W FLOW FROM 8N TO 14N BETWEEN 85W AND 105W WITH SEAS THERE UP TO 9 FT. A CYCLONIC CIRCULATION DENOTING A 1004 MB LOW...LIKELY PORTIONS OF THE REMNANT LOW OF MATTHEW...NEAR 14N92W WAS DRIFTING E TO NEAR THE COAST OF MEXICO AND HAS BEEN GENERATED SMALL CLUSTERS OF MODERATE TO STRONG CONVECTION DURING THE PAST 12 HOURS. MIDDAY ASCAT PASSES SHOWED SW WINDS OF 20 KT S OF THE ITCZ FROM 106W EXTENDING ENE TO THE COAST OF GUATEMALA AND SAN SALVADOR. THIS LOW IS FORECAST TO MOVE INLAND AND WEAKEN AS IT CROSSES CENTRAL AMERICA IN THE NEXT FEW DAYS. N WINDS OF 20 TO 25 KT ARE EXPECTED TO BECOME ESTABLISHED THROUGH THE ISTHMUS OF TEHUANTEPEC IN ABOUT 30 HOURS. ELSEWHERE...15-17 SEC LONG PERIOD SWELL CONTINUES TO PUSH SE FROM THE N CENTRAL PACIFIC IN TO THE DISCUSSION AREA. SEAS ARE SUBSIDING SOME OVER THE NW PORTION OF THE AREA. THIS INITIAL SWELL TRAIN WILL CONTINUE TO SPREAD SE ACROSS NW HALF OF THE BASIN AND GRADUALLY SUBSIDE. A SECOND SURGE OF NW SWELL WILL REACH FAR NW WATERS BY LATE THU WITH SEAS REMAINING IN THE 8 TO 9 FT RANGE. MEANWHILE...LONG PERIOD SW SWELL WILL CONTINUE TO AFFECT THE WATERS OF THE FAR EPAC AND CENTRAL AMERICAN COASTS FOR THE NEXT FEW DAYS. $$ STRIPLING