000 AXPZ20 KNHC 011543 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU APR 01 2010 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 1400 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED ALONG 04N77W TO 05N95W TO 06N110W TO 05N130W TO 04N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 60 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 133W AND 136W. TWO TROUGHS ARE EMBEDDED IN THE ITCZ. THE EASTERN TROUGH FROM WAS FROM 06N83W TO 01N83W AND HAD SCATTERED MODERATE CONVECTION WITHIN 60 NM EITHER SIDE OF THE TROUGH. THE WESTERN TROUGH WAS FROM 09N121W TO 03N124W AND HAD SCATTERED MODERATE CONVECTION WITHIN 270 NM W AND 120 NM E OF THE TROUGH N OF 06N AS WELL AS WITHIN 60 NM EITHER SIDE OF THE TROUGH S OF 04N. ...DISCUSSION... SUBTROPICS... A SHARP LONG-WAVE TROUGH IS MOVING INTO THE WESTERN U.S. AND NW MEXICO. SHORTWAVE ENERGY SW OF THIS MAIN TROUGH EXTENDS THE TROUGH AXIS OVER FORECAST WATERS FROM 30N116W TO 28N116W TO 16N140W. THIS ENERGY WILL DECOUPLE FROM THE PROGRESSIVE MAIN UPPER TROUGH DURING THE FORECAST PERIOD. AT THE SURFACE...N TO NW WINDS TO 25 KT WERE OBSERVED BY THE 0510 ASCAT PASS N OF 28N E OF 134W. THESE WINDS WERE CONFIRMED BOTH THERE AND WITHIN 150 NM W OF BAJA CALIFORNIA BY SEVERAL SHIP OBSERVATIONS AT 1200 UTC. THE SHIPS ALSO CONFIRM THE WW3 MODEL MAX SIGNIFICANT WAVE HEIGHTS AT 18 FT OVER NE WATERS. THESE WINDS WILL SHIFT E WITHIN 150 NM OF THE W COAST OF BAJA CALIFORNIA TOMORROW AS THE MAIN TROUGH AND THE TIGHTEST PRES GRADIENT SHIFTS E. A DEEP LAYER RIDGE LIES JUST NW OF THE AREA. THE UPPER RIDGE WILL BE FORCED W OVER THE NEXT TWO DAYS AS ENERGY FROM THE N PACIFIC ENCROACHES ON ITS N EDGE AND THE LINGERING SHORTWAVE ENERGY OVER W WATERS WEAKENS THE RIDGING ON ITS SE SIDE. AT THE SURFACE...THE RIDGE AXIS WILL WEAKEN AND BE FORCED SOUTHWARD BY A COLD FRONT ASSOCIATED WITH THE ENERGY MOVING IN FROM THE N. THIS WILL SHIFT THE BAND OF TRADE WINDS CURRENTLY FROM 06N TO 25N W OF 130W SOUTHWARD TO 09N TO 18N W OF 120W BY SAT MORNING. TROPICS... THERE ARE TWO TROUGHS EMBEDDED IN THE ITCZ NOTED IN THE ITCZ SECTION ABOVE. THE WESTERN TROUGH IS THE MORE CONVECTIVELY ACTIVE SYSTEM. IT LIES UNDER BROAD UPPER LEVEL DIFFLUENCE BETWEEN A WEAK NEGATIVELY-TILTED UPPER TROUGH FROM 112N132W TO 08N114W AND A RIDGE TO THE W FROM A DEVELOPING ANTICYCLONE NEAR 06N94W TO 12N102W TO NEAR MANZANILLO MEXICO. THE EASTERN TROUGH LIES ON THE WEST EDGE OF A RIDGE AXIS THAT EXTENDS E INTO NORTHERN COLOMBIA. PRECIPITABLE WATER SATELLITE IMAGERY SHOWS LOW TO MID LEVEL MOISTURE IS POOLING IN THESE SE WATERS AND THE FORECAST CALLS FOR CONTINUED DIFFLUENT CONDITIONS ALOFT...SO CONVECTION IS LIKELY TO CONTINUE NEAR THE ITCZ E OF 90W OVER THE NEXT DAY OR TWO. GAP WINDS... THE 0322 UTC ASCAT PASS CAUGHT THE FAR W EDGE OF THE NARROW PLUME OF GAP WINDS THROUGH THE GULF OF PAPAGAYO. A STRONG PRES GRADIENT BETWEEN A SLOW MOVING RIDGE AXIS OVER THE GULF OF MEXICO AND LOW PRES OVER COLOMBIA IS GENERATING THESE WINDS. LOOK FOR WINDS TO DIMINISH TO 20 KT BY SAT MORNING AS THE DEEP LAYERED TROUGH CURRENTLY OVER NW MEXICO PUSHES INTO THE WESTERN GULF OF MEXICO AND SHOVES THE RIDGE AXIS EASTWARD...DECREASING THE PRES GRADIENT. IN THE GULF OF CALIFORNIA...THE 0510 UTC ASCAT PASS SHOWED 25 TO 30 KT SW WINDS IN THE NORTHERN GULF AHEAD OF THE LOW LEVEL TROUGH AXIS. THESE WINDS ARE FORECAST TO DIMINISH BY EVENING. NW TO N WINDS WILL THEN INCREASE BEHIND THE TROUGH FRI MORNING OVER THE GULF OF CALIFORNIA S OF 28N. LITTLE CHANGE IS FORECAST IN THESE CONDITIONS THROUGH SAT MORNING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ SCHAUER