000 AXPZ20 KNHC 270349 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE APR 27 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 0245 UTC. ...ITCZ... INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED ALONG 07N77W TO 07N90W TO 07N104W TO 07.5N116W TO 05N131W TO 05N140W. SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION WAS FROM 02N TO 11N BETWEEN 79W AND 96W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 180 NM S AND 120 NM N OF AXIS BETWEEN 96W AND 121W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 120 NM OF AXIS W OF 121W. ...DISCUSSION... A 1025 MB HIGH CENTERED NEAR 25N144W THIS AFTERNOON HAS COLLAPSED THIS EVENING...LEAVING A WEAKENING SURFACE RIDGE AXIS EXTENDING SE TO NEAR 17N120W. HELPING TO WEAKEN THIS HIGH AND ASSOCIATED RIDGE WAS AN ELONGATED MID/UPPER LEVEL TROUGH ACROSS THE NW PORTION OF THE DISCUSSION AREA FROM A SLOW MOVING TROUGH ACROSS SRN CALIFORNIA ACROSS 30N118W TO AN EMBEDDED MID LEVEL VORT CENTER NEAR 22N123W THEN TRAILING W-SW TO BEYOND 16N145W. A S/W UPPER RIDGE WAS DAMMED AGAINST THE NW FLANKS OF THIS TROUGH...EXTENDING SW TO NE ACROSS THE FAR NW CORNER OF THE AREA. A WEAK COLD FRONT EXTENDING NE TO SW WAS JUST CROSSING 30N140W AND WILL BEGIN TO IMPACT THE NORTHWESTERN WATERS OVERNIGHT...SUPPORTED BY A LARGE UPPER LOW OVER THE NE PACIFIC. AS THIS FRONT SKIRTS THE NORTHERN WATERS AND WEAKENS CONSIDERABLY BY WEDNESDAY...THE REMAINS OF THE HIGH ARE FORECAST TO MERGE WITH STRONGER HIGH PRESSURE TO THE N OF THE HAWAIIAN ISLANDS. AFTERNOON ASCAT PASSES SUGGESTED THE AREA OF FRESH NELY TRADES CONTINUE TO ENVELOPE A SMALL AREA FROM ROUGHLY 17N S TO THE ITCZ AND WERE W OF 132W. THIS AREA OF FRESH TRADES IS EXPECTED TO SHRINK THROUGH THE FORECAST PERIOD. MEANWHILE...A 90-140 KT SOUTHWESTERLY UPPER LEVEL JET IS ON THE LEADING EDGE OF THE TROUGH...FROM NEAR 15N138W TO THE S HALF OF BAJA CALIFORNIA WHERE IT BECOMES MODESTLY DIFFLUENT AS IT VEERS ELY AND MOVES OVER THE TOP OF AN UPPER RIDGE AND ACROSS NRN MEXICO. THIS JET IS TRANSPORTING UPPER LEVEL MOISTURE MANIFESTED AS CIRRUS NORTHEASTWARD FROM THE ITCZ W OF 110W. FINALLY...THE COLD FRONT WILL BRING A SURGE IN NW SWELL WITH SIGNIFICANT WAVE HEIGHTS RISING TO 9 FT W OF THE FRONT BY THIS AFTERNOON. ALOFT...THE REMAINDER OF THE DISCUSSION AREA IS UNDER THE INFLUENCE OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 14N103W THAT IS EXPECTED TO SLOWLY SLIDE EASTWARD AS THE AFOREMENTIONED UPPER LEVEL TROUGH TO THE NW MOVES THROUGH THE NORTHERN WATERS. VERY ACTIVE AND PULSING BUT PERSISTENT CONVECTION NEAR THE ITCZ E OF 145W CONTINUES TO AID IN THE MAINTENANCE OF THIS LARGE RIDGE ACROSS THE TROPICAL EPAC. E OF THE WEAKENING SURFACE RIDGE...A BROAD LOW LEVEL CYCLONIC GYRE PERSISTS BETWEEN 120W AND THE COAST OF COLOMBIA S OF 14N. ABUNDANT TROPICAL MOISTURE CONTINUES TO DRIFT SLOWLY W OFF OF S AMERICA AND CONVERGE ACROSS THIS AREA...LEADING TO SCATTERED TO NUMEROUS MODERATE TO STRONG CONVECTION. RECENT RUNS OF THE GLOBAL MODELS HAVE BEEN SUGGESTING AN AREA OF LOW TO MIDDLE LEVEL CYCLONIC FLOW CURRENTLY EXTENDING FROM THE FAR SW CARIBBEAN W ACROSS COSTA RICA AND PANAMA INTO THE EPAC WILL GAIN SOME ORGANIZATION AND DRIFT NW OVER THE NEXT SEVERAL DAYS. AS THIS ABUNDANT TROPICAL MOISTURE SHIFT W AND NW ACROSS CENTRAL AMERICA AND THEIR PACIFIC COASTS...VERY HEAVY RAINFALL REMAINS POSSIBLE ACROSS PORTIONS OF SOUTHERN CENTRAL AMERICA THE NEXT SEVERAL DAYS. STRONG CONVECTION WILL LIKELY BE ENHANCED E OF 95W AS CONDITIONS ALOFT ARE FORECAST TO REMAIN WITHIN A FAIRLY DIFFLUENT PATTERN. A PORTION OF THE UPPER LEVEL ANTICYCLONE CENTERED NEAR 13N105W WILL DRIFT EASTWARD ACROSS SOUTHERN MEXICO AND LOCATE ITSELF OVER THE WESTERN CARIBBEAN AND CENTRAL AMERICA BY EARLY TUESDAY. FINALLY...LARGE LONG PERIOD NW SWELLS WILL CONTINUE TO PROPAGATE THROUGH THE BASIN AND MERGE WITH CROSS-EQUATORIAL SW SWELL ACROSS THE TROPICS THROUGH WEDNESDAY. $$ STRIPLING