000 AXPZ20 KNHC 290311 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE MAR 29 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 6N78W 4N90W 3N105W...THEN RESUMES AT 4N119W 3N130W 3N140W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF THE AXIS BETWEEN 85W-87W...BETWEEN 88W-91W AND ALSO W OF 138W. ...DISCUSSION... A FAIRLY PROGRESSIVE UPPER FLOW REMAINS IN PLACE 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 EXTENDS SW TO NEAR 22N120W...S TO 14N120W...AND BENDS SE TO NEAR 15N117W. BROAD W TO NW FLOW INTO THE BACKSIDE OF THE TROUGH EXTENDS AS FAR S AS 28N AND TO 127W. S OF THE TROUGH BROAD SWLY FLOW COVERS JUST ABOUT THE ENTIRE AREA TO 9N AND TO THE E OF ANOTHER UPPER LEVEL TROUGH THAT IS TO THE S OF THE FIRST TROUGH ALONG 14N114W 7N113W 2N111W. TO THE W OF THIS TROUGH...THE UPPER FLOW IS BROADLY ANTICYCLONIC AHEAD OF A VERY SHARP UPPER LEVEL TROUGH IN THE VICINITY OF THE HAWAIIAN ISLANDS. A JET STREAM BRANCH RIDES OVER THE NORTHERN CREST OF THE ANTICYCLONIC FLOW ENTERING THE REGION THROUGH 24N140W. IT THEN CONTINUES SE TO 20N125W...AND NE TO ACROSS SOUTHERN BAJA CALIFORNIA TO INLAND CENTRAL MEXICO. UPPER AIR DATA INDICATES MAXIMUM WINDS IN THE RANGE OF 60-70 KT ARE WITHIN ABOUT 480-540 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...A MID/UPPER LEVEL TROUGH IS E OF THE RIDGE ALONG 90W. A REGION OF DIFFLUENCE AHEAD OF THIS TROUGH EARLIER ENHANCED ITCZ CONVECTION QUITE SIGNIFICANTLY BETWEEN 83W-85W...BUT DURING JUST THE PAST FEW HOURS THE CONVECTION HAS DIMINISHED IN BOTH IN INTENSITY AND AREAL COVERAGE BETWEEN 85W-87W. THE TROUGH IS FORECAST TO MOVE E OF THE PACIFIC BASIN AND INTO THE FAR SW CARIBBEAN SEA THROUGH LATE TUE NIGHT WHILE WEAKENING. TO THE SW OF THIS TROUGH A RATHER ELONGATED UPPER LEVEL ANTICYCLONE IS CENTERED JUST W OF THE GALAPAGOS ISLANDS WITH A RIDGE W TO THE SECOND UPPER TROUGH MENTIONED ABOVE. MID/UPPER LEVEL RIDGING IS PRESENT ACROSS THE AREA TO THE S OF THE JET STREAM...AND BETWEEN THE TROUGH ALONG 90W AND THE UPPER TROUGH THAT LIES ALONG 14N116W 7N113W 2N112W. MODERATE SUBSIDENCE ALLOWING FOR GENERALLY STABLE ATMOSPHERIC CONDITIONS ALLOWING FOR VERY LIMITED TO NO MOISTURE TO BE SEEN COVERS THE AREA E OF ABOUT 101W. AT THE SURFACE...A NEARLY STATIONARY 1028 MB HIGH CENTER IS LOCATED JUST NW OF THE AREA NEAR 33N139W WITH A RIDGE SE TO 24N124W TO NEAR 18N114W. 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 20N W OF 130W...WITH A SMALLER AREA OF TRADES 16N TO 21N BETWEEN 110W-130W. A WEAK TROUGH NEAR THE SECOND UPPER TROUGH IS ANALYZED FROM 9N111W TO 6N115W TO 2N119W. ISOLATED SHOWERS AND WEAK TSTMS ARE WITHIN 60-75 NM OF THE TROUGH. THE TRADES ARE EXPECTED TO EXPAND NORTHWARD TO 27N IN 24 HOURS...THEN SHRINK SOME BY 48 HOURS AS THE 1028 MB HIGH INTENSIFIES SOME THEN PULLS TO THE N BY ABOUT 48 HOURS. THE SURFACE TROUGH SHOULD CONTINUE IN A GENERALLY WESTWARD TRACK THROUGH THE NEXT 24-48 HOURS...AND WEAKEN BETWEEN 36-48 HOUR TIME PERIOD. THE PRES GRADIENT BETWEEN THE SUBTROPICAL RIDGE AND LOWER PRES OVER NORTHERN MEXICO CONTINUES TO RESULT IN INITIAL NW TO N WINDS OF 20 KT N OF 24N E OF 124W TO THE BAJA CALIFORNIA COAST. THESE WINDS ARE EXPECTED TO BECOME CONFINED TO WITHIN THE AREA N OF 27N BETWEEN 119W AND 127W IN 24 HOURS...AND TO N OF 27N BETWEEN 120W-128W IN 48 HOURS. ANOTHER SET OF LARGE N SWELLS WITH SEAS UP TO 12 FT IS EXPECTED TO BEGIN TO MOVE INTO THE FAR NE CORNER BEGINNING IN 24 HOURS. $$ AGUIRRE