000 AXPZ20 KNHC 280954 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON JUN 28 2010 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 0945 UTC. ...SPECIAL FEATURES.... TROPICAL STORM CELIA IS CENTERED NEAR 15.3N 124.2W AT 0900 UTC DRIFTING SW OR 220 DEG AT 02 KT. THE MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT...AND THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. CURRENTLY SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 NM OVER THE SW SEMICIRCLE OF THE SYSTEM. CELIA IS EXPECTED TO CONTINUE TO WEAKEN TO A TROPICAL DEPRESSION LATER TODAY AND FURTHER WEAKEN TO A POST TROPICAL REMNANT LOW PRESSURE ON TUE AND OPENING INTO A WEAKENING TROUGH BY THU. REFER TO THE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP4/WTPZ24 KNHC FOR MORE DETAILS. TROPICAL STORM DARBY IS CENTERED NEAR 14.2N 101.4W AT 0900 UTC MOVING E NE OR 060 DEG AT 05 KT. THE MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT...AND THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. EASTERLY SHEAR HAS COMPLETELY EXPOSED THE CENTER WITH NUMEROUS MODERATE TO STRONG CONVECTION SW OF THE EXPOSED CENTER...WITHIN 120 NM EITHER SIDE OF A LINE FROM 15N104W TO 13N103W. DARBY IS EXPECTED TO WEAKEN TO A TROPICAL DEPRESSION TODAY AND FURTHER WEAKEN TO REMNANT LOW PRESSURE ON TUE WITH THE WEAK REMNANTS APPROACHING THE COAST OF MEXICO. REFER TO THE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP5/WTPZ25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE OVER N OF 06N ALONG 95W IS MOVING W AT ABOUT 11 KT. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED N OF 13N BETWEEN 93W AND 97W INCLUDING GULF OF TEHUANTEPEC. ...ITCZ... THE ITCZ AXIS MEANDERS FROM 08N TO 10N E OF 110W TO COLOMBIA THEN EXTENDS FROM 08N110W TO 12N118W TO 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED FROM 06N TO 13N E OF 91W...AND ALSO WITHIN 30 NM EITHER SIDE OF A LINE FROM 10N91W TO 09N102W TO 11N104W...AND ALSO WITHIN 60 NM EITHER SIDE OF A LINE FROM 10N115W TO 12N121W. ...DISCUSSION... A SMALL UPPER CYCLONE IS CENTERED NEAR 32N123W WITH A TROUGH SW TO 20N126W. THE UPPER ANTICYCLONE ASSOCIATED WITH TROPICAL STORM CELIA IS CENTERED NEAR 18N115W WITH A RIDGE EXTENDING W TO A CREST NEAR W OF THE AREA 11N146W. A TONGUE OF UPPER MOISTURE... ORIGINATING FROM ITCZ CONVECTION NEAR 145W...IS SPREADING N ACROSS THE RIDGE AND OVER THE DISCUSSION AREA FROM 22N TO 29N W OF 137W. THE DEBRIS MOISTURE FROM CELIA IS CONFINED TO WITHIN 120 NM OF 16N125W. AN UPPER CYCLONE IS NOTED S OF THE UPPER RIDGE AND THE LOW LEVEL ITCZ NEAR 04N132W. A NEGATIVE TILT UPPER TROUGH ENTERS THE DISCUSSION AREA NEAR 32N110W AND EXTENDS SE OVER WESTERN OLD MEXICO TO OVER THE PACIFIC AT 20N106W...AND CONTINUES S INTO A SMALL UPPER CYCLONE AT 10N111W...WITH THE TROUGH STILL EVIDENT CROSSING THE EQUATOR NEAR 113W. THIS TROUGH EFFECTIVELY SEPARATES THE UPPER LEVEL PATTERN OVER THE DISCUSSION AREA. UPPER DIFFLUENCE W OF THIS TROUGH...AND SE OF THE ANTICYCLONE ASSOCIATED WITH CELIA... ENHANCES CONVECTION ALONG THE ITCZ BETWEEN 113W AND 122W WITH THE DEBRIS MOISTURE CONCENTRATED TO WITHIN 180 NM EITHER SIDE OF A LINE FROM 08N112W TO 13N112W. OTHERWISE THE UPPER LEVELS ARE DRY N OF 20N W OF 105W AND S OF 20N W OF 112W. AN UPPER ANTICYCLONE IS CENTERED OVER THE SW BAY OF CAMPECHE AND IS ASSOCIATED WITH ATLANTIC TROPICAL STORM ALEX. AN UPPER RIDGE EXTENDS SW JUST TO THE N OF TROPICAL STORM DARBY TO A CREST NEAR 15N111W. THE OVERALL ENVELOPE OF ANTICYCLONIC FLOW IS QUITE LARGE...DOMINATING THE DISCUSSION FROM 30N TO 05S BETWEEN 112W AND 75W. THE DEBRIS MOISTURE FROM THE TS ALEX CONVECTION...AND FROM THE CONVECTION ENHANCED ALONG THE TROPICAL WAVE AND THE ITCZ BOTH PREVIOUSLY MENTIONED...AND THE CONVECTION ASSOCIATED WITH TROPICAL STORM DARBY...IS ALL FANNING OUT OVER THE AREA FROM 20N TO 05S BETWEEN 110W AND 75W. AT THE SURFACE...HIGH PRESSURE NW OF AREA RIDGES E ALONG 32N138W TO 20N120W. THE GRADIENT E OF THE RIDGE CONTINUES TO PRODUCE NW 20 KT WINDS WITHIN 300 NM OF THE SOUTHERN BAJA PENINSULA. THE TROPICAL CYCLONES HAVE GENERATED MULTIPLE SWELL FIELDS RESULTING IN CONFUSED SWELL OVER MOST OF THE AREA SURROUNDING THE CYCLONES...ROUGHLY S OF 20N W OF 105W...AND IS ALSO MIXING WITH CROSS EQUATORIAL SOUTHERLY SWELL. THESE SOUTHERLY SWELLS ARE ALSO MIXING WITH N SWELL OVER THE WATERS N OF 20N BETWEEN 110W AND 135W WITH THE SOUTHERLY SWELL EXPECTED TO DAMPEN OUT AS THE N SWELL BECOMES PREDOMINATE AS THE GRADIENT ASSOCIATED WITH THE SURFACE RIDGE TIGHTENS IN THE WAKE OF A COLD FRONT BY MID WEEK. THE GRADIENT IS ALSO TIGHT SE OF THE TROPICAL STORM DARBY WITH THE SW MONSOON FLOW ENHANCED BY THE DEEPENING LOW PRESSURE OF ATLANTIC TROPICAL STORM ALEX IN THE E BAY OF CAMPECHE. ANOTHER BOUT OF REINFORCING SOUTHERLY SWELL IS JUST BEGINNING TO CROSS THE EQUATOR E OF 130W. $$ NELSON