000 AXPZ20 KNHC 042200 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI JUN 04 2010 CORRECTED TO INCLUDE MENTION OF WESTERN MOST TROUGH IN THIRD PARAGRAPH UNDER DISCUSSION TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2015 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 07N78W TO 12N92W TO 09N100W TO 12N121W TO 06N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 60 NM AND 75 NM S OF THE ITCZ AXIS BETWEEN 96W AND 102W...WITHIN 150 NM S OF THE ITCZ AXIS BETWEEN 113W AND 118W...AND WITHIN 150 NM N AND 90 NM S OF THE ITCZ AXIS W OF 138W. THREE SURFACE TROUGHS ARE EMBEDDED IN THE ITCZ. THE EASTERN TROUGH WAS FROM 14N91W TO 07N94W AND HAD ISOLATED MODERATE CONVECTION WITHIN 120 NM W OF THE TROUGH AND N OF 12N WITHIN 120 NM E OF THE TROUGH. THE SECOND TROUGH WAS FROM 13N119W TO 07N124W AND HAD SCATTERED MODERATE CONVECTION WITHIN 210 NM E OF THE TROUGH N OF 08N AND WITHIN 150 NM W OF THE TROUGH FROM 08N TO 11N. THE WESTERN TROUGH WAS FROM 13N119W TO 07N124W AND HAD SCATTERED MODERATE CONVECTION WITHIN 210 NM E OF THE TROUGH N OF 08N AND WITHIN 150 NM W OF THE TROUGH FROM 08N TO 11N. ...DISCUSSION... SUBTROPICS... THE AMPLIFIED UPPER PATTERN IN PLACE N OF 20N...WITH AN UPPER LOW OVER THE NW GULF OF MEXICO AND AN ANTICYCLONE OVER THE SW UNITED STATES...IS EXPECTED TO CHANGE LITTLE OVER THE NEXT TWO DAYS. THE TAIL OF THE UPPER TROUGH ASSOCIATED WITH THE GULF OF MEXICO LOW HAS PINCHED OFF TWO UPPER LOWS...ONE NEAR 22N120W AND ANOTHER NEAR 27N136W. THESE LOWS ARE EXPECTED TO SLOWLY MERGE...WITH THE RESULTING UPPER LOW NEAR 27N122W BY SUN AFTERNOON AND THE ANTICYCLONE TO ITS NE SHIFTING CLOSER TO THE U.S. FOUR CORNERS. CURRENTLY...THE WESTERN UPPER LOW HAS A 50 KT WESTERLY JET TO ITS SW ALONG 12N. LEFT FRONT QUADRANT JET DIFFLUENCE IS ENHANCING CONVECTION NEAR A TROUGH EMBEDDED IN THE ITCZ W OF THE AREA. THIS CONVECTION EXTENDS INTO FAR W WATERS NEAR THE ITCZ AND THE UPPER JET IS TRANSPORTING BOTH HIGH CLOUDS AND CONVECTIVE BLOW OFF EAST-NORTHEASTWARD INTO THE FORECAST AREA. THE JET MAX IS EXPECTED TO LIFT NE AS THE TWO UPPER LOWS MERGE OVER THE NEXT TWO DAYS...MOVING AWAY FROM THE LOW LEVEL MOISTURE POOLED NEAR THE ITCZ. AT THE SURFACE...1021 MB HIGH PRES NEAR 28N129W WILL DRIFT W AND STRENGTHEN OVER THE NEXT TWO DAYS. THE HIGH WILL BE HELD SOUTH OF 30N BY A SERIES OF NORTHERN STREAM COLD FRONTS PASSING TO ITS N. NW TO N WINDS OFF THE CALIFORNIA COAST INDUCED BY THE PRESSURE GRADIENT BETWEEN LOWER PRES OVER THE GREAT BASIN AND THE RIDGE EXTENDING FROM THE HIGH CENTER TO THE CENTRAL CALIFORNIA COAST HAVE BROUGHT 8 FT NW SWELL INTO NE WATERS WHILE NW SWELL ASSOCIATED WITH THE COLD FRONT HAS BROUGHT SEAS TO 8 FT OVER NW WATERS. 20 KT WINDS WILL SHIFT S INTO FORECAST WATERS OVERNIGHT TONIGHT AS THE COLD FRONT CURRENTLY MOVING INTO THE PACIFIC NW STATES PUSHES SE INTO THE WESTERN U.S. AND FURTHER INCREASES THE PRESSURE GRADIENT. THE TWO SURGES OF NW SWELL WILL MERGE OVER NE WATERS SAT EVENING. MEANWHILE...TRADE WINDS HAVE BEEN REDUCED TO 20 KT UNDER THE INFLUENCE OF THE WEAK SUBTROPICAL HIGH AND WILL DROP BELOW 20 KT SAT BEFORE BECOMING REINVIGORATED SUN WHEN HIGH PRESSURE SHIFTS W AND BEGINS TO BUILD. TROPICS... DIFFLUENT FLOW BETWEEN THE SW SIDE OF THE UPPER LEVEL ANTICYCLONE OVER THE CARIBBEAN NEAR 19N84W AND THE NW SIDE OF THE ANTICYCLONE OVER SOUTH AMERICA NEAR 11S57W LIES ON THE W SIDE OF THE EASTERN SURFACE TROUGH MENTIONED IN THE ITCZ SECTION. UPPER LEVEL NORTHEASTERLY WINDS ARE EXPECTED TO STRENGTHEN OVER THE TROUGH AS THE ANTICYCLONE OVER THE CARIBBEAN SHIFTS NE. ALSO...THE DEEP LAYER MOISTURE MAXIMUM PREVIOUSLY NEAR THIS SYSTEM HAS PUSHED AHEAD OF IT TO THE W. THIS SHOULD DECREASE THE LIKELIHOOD OF DEEP CONVECTION. THE TROUGH JUST TO ITS W LIES WITHIN A REGION OF INCREASING DEEP LAYER MOSITURE AND IS EXPECTED TO REMAIN UNDER AN UPPER RIDGE AXIS EXTENDING E FROM AN ANTICYCLONE NEAR 12N111W THAT IS NOT EXPECTED TO MOVE MUCH OVER THE NEXT FEW DAYS. THIS SHOULD ALLOW CONVECTION TO CONTINUE NEAR THE TROUGH. THE WESTERN TROUGH EMBEDDED IN THE ITCZ CONTINUES TO BE A FOCUS FOR CONVECTION AS AN AREA OF DEEP LAYER MOSITURE CONTINUES TO BE CONVERGED NEAR THIS TROUGH. THE 1714 ASCAT PASS SHOWS 20 KT WINDS CAN BE FOUND ON EITHER SIDE OF THE TROUGH AND A LOW APPEARS TO BE FORMING ALONG IT NEAR 10N. THIS LOW IS EXPECTED TO PERSIST FOR THE NEXT FEW DAYS AS THE TROUGH CONTINUES TO LIE UNDER AN UPPER RIDGE EXTENDING W FROM THE AFOREMENTIONED ANTICYCLONE NEAR 12N111W. $$ SCHAUER