000 AXPZ20 KNHC 011522 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT MAY 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 1330 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 11N86W TO 04N102W TO 05N115W TO 05N130W TO 03N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 210 NM N OF THE ITCZ AXIS BETWEEN 98W AND 101W. SCATTERED MODERATE CONVECTION WAS ELSEWHERE WITHIN 360 NM N AND 120 NM S OF THE ITCZ AXIS BETWEEN 99W AND 104W. SCATTERED MODERATE CONVECTION WAS WITHIN 60 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 123W AND 129W. A TROUGH IS EMBEDDED IN THE ITCZ FROM 14N92W TO 11N88W TO 06N87W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 90 NM SW OF THE TROUGH N OF 12N WHILE SCATTERED MODERATE CONVECTION WAS ELSEWHERE WITHIN 240 NM SW AND 150 NM NE OF THE TROUGH. ...DISCUSSION... SUBTOPICS... A HIGHLY AMPLIFIED UPPER PATTERN IS IN PLACE WITH A POSITIVELY TILTED TROUGH FROM THE U.S. FOUR CORNERS TO NEAR 23N116W WEDGED BETWEEN AN UPPER LEVEL RIDGE AXIS N OF 23N ALONG 141W AND AN ANTICYCLONE CENTERED OVER THE YUCATAN NEAR 90N90W. THE MEAN RIDGE-TROUGH-RIDGE PATTERN IS EXPECTED TO REMAIN IN PLACE FOR THE NEXT TWO DAYS AND REACH FARTHER S INTO THE TROPICS AS THE ANTICYCLONE OVER THE YUCATAN REMAINS STATIONARY...BLOCKING THE E PROGRESS OF THE TROUGH. AT THE SAME TIME...A NEW ANTICYCLONE NOW S OF HAWAII WILL JOIN FORCES WITH THE RIDGE TO THE W OF THE TROUGH AND SHORTWAVE ENERGY CURRENTLY FOUND BOTH N AND S OF THIS RIDGE WILL MOVE INTO THE SW EDGE OF THE TROUGH AXIS TOMORROW...SENDING THE MEAN TROUGHING FARTHER S INTO THE TROPICS. AT THE SURFACE...1035 MB HIGH PRES NEAR 35N143W WITH A RIDGE EXTENDING SE INTO THE FORECAST AREA THROUGH 30N132W TO 15N115W DOMINATES THE SENSIBLE WEATHER OVER THE FORECAST AREA. SCATTERED TO BROKEN STRATOCUMULUS WAS FOUND N OF 15N W OF 100W...WITH ONLY SOME SCATTERED CIRRUS BLOW OFF FROM CONVECTION FURTHER S FOUND S OF 13N BETWEEN 100W AND 110W. THE ASCAT PASSES FROM 0446 AND 0626 UTC SHOW FRESH TO MODERATE TRADE WINDS W OF THE RIDGE AXIS AND NW TO N WINDS E OF THE RIDGE AXIS. THE EARLIER ASCAT PASS ALONG WITH AN UNKNOWN SHIP NEAR 21N109W AND SHIP C6SE7 NEAR 22N109W SHOW THE MODERATE NW WINDS AND SEAS TO 10 FT EXTEND TO THE MOUTH OF THE GULF OF CALIFORNIA. STRONG WINDS E OF THE RIDGE AXIS ARE THE RESULT OF A 30-40 MB PRES GRADIENT BETWEEN THE RIDGE AND RELATIVELY DEEP LOW PRES CENTERED OVER TEXAS AND E OF THE SIERRA MADRE OCCIDENTAL. WHILE EARLIER ASCAT PASSES SHOWED WINDS ABOVE 20 KT IN THE SOUTHERN GULF OF CALIFORNIA...THE MOST RECENT PASSES MISSED THIS AREA. WINDS ARE BELIEVED TO BE AT OR ABOVE 20 KT AT THE MOMENT...BUT ARE EXPECTED TO DIMINISH IN THE GULF OF CALIFORNIA LATER TODAY. THE PRES GRADIENT WILL RELAX SOMEWHAT THROUGH MON AS THE TROUGHING OVER THE CENTRAL U.S. AND GULF OF MEXICO WEAKENS AND SHIFTS E. IN ADDITION...THE HIGH PRES CENTER OVER THE PACIFIC IS EXPECTED TO WEAKEN AS A NEW SYSTEM MOVES N OF HAWAII AND SLOWLY IMPINGES UPON IT FROM THE W SUN AND MON. HOWEVER...A NEW SYSTEM MOVING THROUGH THE GREAT BASIN AND SW U.S. OVERNIGHT INTO SUN WILL HELP KEEP THE GRADIENT STRONG OVER N WATERS. TROPICS... A LOW TO MID LEVEL CYCLONIC GYRE LIES ALONG THE E EDGE OF THE ITCZ. A SURFACE TROUGH IS EMBEDDED IN THE ITCZ HERE FROM 14N92W TO 11N88W TO 06N87W. UPPER LEVEL FLOW OVER THIS TROUGH IS DIFFLUENT AS IT LIES ON THE SE SIDE OF A STRENGTHENING ANTICYCLONE CENTERED OVER THE YUCATAN PENINSULA. CONVECTION NEAR THE TROUGH IS NOTED IN THE ITCZ SECTION ABOVE. THE CENTER OF THIS ANTICYCLONE WILL ONLY MOVE SLOWLY TO THE E WHILE THE RIDGE AXIS EXPANDS SW FROM THE CENTER TO S OF THE GULF OF TEHUANTEPEC SUN AND LIFTING N THROUGH SOUTHERN MEXICO ALONG 19N BUT EXPANDING TO 10N115W MON. THE MOVEMENT OF THE RIDGE AXIS SHOULD ALLOW CONVECTION TO SHIFT FROM THIS TROUGH TO THE SW TOWARD THE ITCZ OVER CENTRAL WATERS THROUGH MON...ESPECIALLY AS UPPER LEVEL WINDS ARE EXPECTED TO BECOME MORE CONFLUENT OVER SE WATERS BETWEEN THIS ANTICYCLONE AND ONE EXPECTED TO PINCH OFF OVER NORTHERN PERU AND DRIFT W THROUGH SUN. CONVECTION MAY BEGIN TO RETURN NEAR PANAMA ON MON AS CONDITIONS BECOME MORE FAVORABLE. MEANWHILE...DIFFLUENT FLOW AROUND A WEAK UPPER RIDGE OVER THE ITCZ AROUND 120W HAS INDUCED SCATTERED MODERATE CONVECTION BETWEEN THIS RIDGE AXIS AND A TROUGH EMBEDDED IN THE ITCZ FROM 09N131W TO 02N133W. FINALLY...CROSS-EQUATORIAL SW SWELL WILL MOVE INTO SOUTHERN PORTION OF THE AREA W OF 115W ON SUN MORNING AND REACH 10N BY MON MORNING. $$ SCHAUER