000 AXPZ20 KNHC 280256 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON MAR 28 2011 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 0315 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS CENTERED ALONG 7N81W 5N91W 4N101W 5N114W 2N125W 3N140W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM N OF THE AXIS BETWEEN 125W-129W...AND ALSO BETWEEN 134W-138W. ...DISCUSSION... A FAIRLY PROGRESSIVE UPPER FLOW REMAINS IN PLACE ALOFT ACROSS THE DISCUSSION AREA. THE TAIL END OF A DAMPENING UPPER TROUGH NOW OVER THE WESTERN U.S. EXTENDS SW INTO THE REGION THROUGH 32N119W AND REACHES TO NEAR 24N127W. BROAD W TO NW FLOW INTO THE BACKSIDE OF THE TROUGH EXTENDS AS FAR S AS 28N AND E OF 131W. S OF THE TROUGH BROAD SWLY FLOW COVERS JUST ABOUT THE ENTIRE AREA TO 9N AND TO THE E OF AN UPPER LEVEL TROUGH THAT STRETCHES FROM 20N131W SE TO 13N127W TO 5N123W. TO THE W OF THIS TROUGH...THE UPPER FLOW IS VASTLY ANTICYCLONIC. A JET STREAM BRANCH RIDES OVER THE NORTHERN CREST OF THE ANTICYCLONIC FLOW ENTERING THE REGION THROUGH 20N140W. IT THEN CONTINUES ENE TO 21N125W...AND TO ACROSS SOUTHERN BAJA CALIFORNIA TO INLAND CENTRAL MEXICO. UPPER AIR DATA INDICATES MAXIMUM WINDS IN THE RANGE OF 60-80 KT ARE WITHIN ABOUT 360 NM S OF THIS JET. THESE WINDS ARE ADVECTING UPPER LEVEL MOISTURE IN THE FORM OF MOSTLY BROKEN HIGH CIRRUS CLOUDS FROM THE DEEP TROPICS OF THE CENTRAL PACIFIC NORTHEASTWARD TO ACROSS THE FAR EASTERN PORTION OF THE AREA FROM 17N-22N AND TO THE E OF THE UPPER TROUGH. OVER THE FAR SOUTHERN PORTION OF THE AREA...MID/UPPER LEVEL RIDGING IS PRESENT S OF THE JET STREAM AND TO THE E OF THE SECOND UPPER LEVEL TROUGH MENTIONED ABOVE BETWEEN 99W-127W. A RATHER SHARP MOSTLY MID LEVEL TROUGH IS NOTED FROM NEAR 9N98W TO 2N94W. THIS TROUGH HAD EARLIER SET OFF SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 180 NM TO ITS E ALONG THE ITCZ. THIS ACTIVITY HAS SINCE DISSIPATED IN MODERATE TO STRONG SUBSIDENCE AS NOTED IN WATER VAPOR IMAGERY. TO THE SE OF THIS TROUGH...A SMALL UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 3N86W WITH A RIDGE NNW TO 10N90W. MODERATE SUBSIDENCE ALLOWING FOR GENERALLY STABLE ATMOSPHERIC CONDITIONS ALLOWING FOR VERY LIMITED TO NO MOISTURE TO BE SEEN COVERS THE AREA E OF ABOUT 107W. AT THE SURFACE...A WEAKENING COLD FRONT ASSOCIATED WITH THE ABOVE MENTIONED UPPER TROUGH IS APPROACHING 32N140W. THE FRONT WILL CONTINUE TO WEAKEN THROUGH THE NEXT 48 HOURS AS HIGH PRES BUILDS IN BEHIND IT. CURRENTLY...A 1026 MB HIGH CENTER LOCATED NW OF THE AREA NEAR 33N149W EXTENDS A RIDGE E TO 32N128W...THEN SE NEAR 23N115W. HIGH PRES COVERS THE DISCUSSION AREA N OF 14N AND W OF 113W. FRESH NE TRADE WINDS ARE PRESENT S OF THE RIDGE AXIS FROM 4N TO 19N W OF 125W...WHILE A WEAK TROUGH IS ANALYZED FROM 8N111W TO 3N114W. CONVERGENCE TO THE W OF THE TROUGH HAD RECENTLY AIDED IN THE DEVELOPMENT OF ITCZ CONVECTION...HOWEVER THIS CONVECTION HAS SIGNIFICANTLY WEAKENED JUST DURING THE PAST FEW HOURS. THE TRADES ARE EXPECTED TO EXPAND NORTHWARD TO ABOUT 24 HOURS AS THE HIGH PRES BUILDING EASTWARD BEHIND THE WEAKENING FRONT STRENGTHENS SOME THROUGH TUE NIGHT. THE SURFACE TROUGH SHOULD CONTINUE IN A GENERALLY WESTWARD TRACK THROUGH THE NEXT 24-36 HOURS...WITH SOME SLIGHT DAMPENING EXPECTED BETWEEN 36-48 HOURS. THE PRES GRADIENT BETWEEN THE SUBTROPICAL RIDGE AND LOWER PRES OVER NORTHERN MEXICO IS RESULTING IN NW TO N WINDS OF 20-25 KT N OF 24N E OF 117W TO THE BAJA CALIFORNIA COAST. THESE WINDS ARE EXPECTED TO BECOME CONFINED TO WITHIN THE AREA N OF 27N BETWEEN 119W AND 128W IN 48 HOURS. $$ AGUIRRE