000 AXPZ20 KNHC 061558 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC TUE MAY 06 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...ITCZ... INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...05N77W TO 08N92W TO 06N120W TO 05N130W TO 06N140W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE WITHIN 240 NM OF THE ITCZ AXIS FROM 100W TO 123W. ...DISCUSSION... W OF 110W... A DEEP MID- TO UPPER-LEVEL CUT-OFF CYCLONE EMBEDDED WITHIN A LARGER-SCALE SOUTHERN STREAM TROUGH IS HOVERING NEAR THE SOUTHERN CALIFORNIA COAST...WITH THE LARGER-SCALE TROUGH EXTENDING WELL SW THROUGH 21N124W TO 17N140W. THIS PATTERN HAS FAVORED BROAD SURFACE LOW PRESSURE OVER THE DESERT SW AND CALIFORNIA THE PAST FEW DAYS...WHICH COMBINED WITH HIGH PRESSURE OVER THE NE PACIFIC NEAR 36N138W...HAS LED TO INCREASED NORTHERLY FLOW OFFSHORE THE CALIFORNIA COAST. THE NORTHERLY FLOW HAS TEMPORARILY DECREASED TODAY...WITH MOST OF THE GREATER THAN 20 KT WINDS NOW N OF THE AREA. DESPITE THAT...SEAS OF 8 TO 10 FT IN N SWELL CONTINUES TO FILTER SOUTHWARD FROM OFFSHORE THE CALIFORNIA COAST...BUT SEAS SHOULD GRADUALLY SUBSIDE DURING THE NEXT 24 TO 48 HOURS. THEREAFTER...ANOTHER WEAKER SHORTWAVE UPSTREAM REACHING THE WEST COAST SHOULD EJECT THE CALIFORNIA CLOSED LOW INTO THE SW CONUS...ANCHORING THE CURRENT PATTERN IN PLACE THROUGH AT LEAST LATE WEEK. WITH THE ARRIVAL OF THE NEXT DISTURBANCE TOMORROW...AN ENHANCED NORTHERLY FLOW SHOULD AGAIN RE-DEVELOP AND SLOWLY DIMINISH THROUGH LATE WEEK. ELSEWHERE...A PATTERN OF ENHANCED SURFACE HIGH PRESSURE IN THE WAKE OF THE WEST COAST TROUGH ARCS SW INTO THE TROPICAL EAST PACIFIC...KEEPING TRADES NEAR OR ABOVE CLIMATOLOGICAL AVERAGES IN AN AREA ROUGHLY RUNNING FROM 6N TO 20N W OF ABOUT 120W. IN FACT...A MORNING SCATTEROMETER PASS OVER THIS REGION SHOWS SPOTTY 20 KT WINDS...WITH THE GREATEST CONCENTRATION W OF 130W. SEAS HAVE BUILT SOME SINCE YESTERDAY IN NE WIND WAVES ...WITH WAVE HEIGHTS RANGING FROM 6 TO 9 FT...HIGHEST TO THE S. MODEL GUIDANCE SUGGEST A SUBTLE EXPANSION TO INCREASED SEAS OVER THIS AREA THROUGH MID-WEEK...THANKS TO THE ENHANCED TRADE WIND FLOW. OTHERWISE...WATER VAPOR IMAGERY AND CLOUD-TRACKED WINDS CONTINUE TO SHOW A WELL-DEFINED BAND OF ANOMALOUS WESTERLY FLOW ALONG THE EQUATOR EXTENDING FROM THE DATELINE TO 85W. THE ANOMALOUS WESTERLY FLOW OF 30 TO 80 KT IS PRECEDING A NEARLY STATIONARY AREA OF TROPICAL CONVECTIVE FORCING...WHICH HAS MOVED FROM THE INDIAN OCEAN INTO THE FAR WESTERN PACIFIC THE LAST TWO WEEKS. THIS CONVECTIVE SIGNAL SHOULD CONTINUE TO CRAWL EASTWARD INTO THE WESTERN AND PERHAPS THE CENTRAL NORTH PACIFIC IN THE NEXT WEEK OR SO...THOUGH THE COOLER-THAN -AVERAGE SEA SURFACE TEMPERATURES ASSOCIATED WITH LA NINA SHOULD SQUASH ANY ENHANCED CONVECTION THAT MIGHT MOVE INTO THE CENTRAL OR EASTERN PACIFIC. SHOULD THE CONVECTION HOLD TOGETHER MORE THAN EXPECTED...THE ARRIVAL OF THIS SIGNAL OVER THE EASTERN HALF OF THE PACIFIC COULD SPARK THE BEGINNING OF THE EASTERN NORTH PACIFIC HURRICANE SEASON. FINALLY...A WELL-DEFINED COLD LOW EMBEDDED IN THE STRONG WESTERLY CURRENT ALOFT IS EVIDENT IN WATER VAPOR IMAGERY NEAR 20N135W. A STRONGLY DIFFLUENT FLOW EAST OF THE CIRCULATION IS ENHANCING CONVECTION WITHIN THE ITCZ BETWEEN 110-125W AND CLOUD COVER TO 130W S OF 25N. E OF 110W... A DOMINANT MID- TO UPPER-LEVEL RIDGE STRETCHES FROM THE WESTERN CARIBBEAN THROUGH CENTRAL MEXICO...WITH ITS AXIS SPREADING JUST BEYOND W OF 110W. UNDERNEATH THE WESTERN SIDE OF THE RIDGE ALOFT...SCATTERED CONVECTIVE ELEMENTS CONTINUE TO SHIFT WESTWARD ALONG OR N OF THE ITCZ BETWEEN 100W AND 110W. THIS SYSTEM APPEARED BETTER-ORGANIZED SUN AND MON...EXHIBITING SOME SIGNS THAT SLOW TROPICAL CYCLONE DEVELOPMENT MIGHT HAVE BEEN OCCURRING. HOWEVER...SINCE THAT TIME...AN INCREASING WESTERLY FLOW ALOFT AND PERHAPS OTHER FACTORS HAVE RESULTED IN NOTHING MORE THAN A CHAOTIC CONVECTIVE PATTERN. ELSEWHERE...WINDS GENERALLY REMAIN LIGHT ACROSS THE REGION...EXCEPT DOWNWIND OF THE GULF OF PAPAGAYO WHERE NE TO E 20 KT WINDS HAVE BEEN BLOWING FROM OVERNIGHT INTO THIS MORNING. SEAS GENERALLY RANGE FROM 5 TO 7 FT OFFSHORE THE MEXICAN AND CENTRAL AMERICAN COASTS INTO THE OPEN TROPICAL EASTERN PACIFIC IN A CONTINUATION OF THE LONG PERIOD SW SWELL PROPAGATING OUT OF THE SOUTHERN HEMISPHERE EXTRATROPICS. SEAS IN VICINITY OF THE GULF OF PAPAGAYO COULD BE LOCALLY UP TO 8 FT...HOWEVER. GOING FORWARD...NO AREAS MEETING HIGH WIND CRITERIA OR WITH SEAS GREATER THAN 8 FT ARE ANTICIPATED THROUGH AT LEAST MID-WEEK. $$ KIMBERLAIN