000 AXPZ20 KNHC 301532 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI APR 30 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 10N84W TO 07N99W TO 05N113W TO 04N126W TO 05N140W. SCATTERED MODERATE ISOLATED WITH STRONG CONVECTION WAS WITHIN 210 NM S AND 30 NM N OF THE ITCZ AXIS BETWEEN 87W AND 101W AS WELL AS WITHIN 150 NM S AND 90 NM N OF THE ITCZ AXIS BETWEEN 105W AND 115W. A TROUGH IS EMBEDDED IN THE ITCZ FROM 14N93W TO 12N89W TO 04N87W. SCATTERED MODERATE CONVECTION WAS E OF TROUGH TO THE COAST FROM 10N TO 13N AND WITHIN 270 NM E OF TROUGH S OF 06N. ...DISCUSSION... SUBTOPICS... ALOFT...A POSITIVELY TILTED UPPER LEVEL TROUGH LIES FROM THE U.S. FOUR CORNERS THROUGH SAN DIEGO CALIFORNIA TO NEAR 23N130W THIS MORNING WHILE AN UPPER LEVEL RIDGE AXIS CAN BE FOUND TO ITS W GENERALLY N OF 20N BETWEEN 143W AND 148W. BROKEN STRATOCUMULUS WAS OVER MUCH OF THE AREA N OF 15N W OF 110W. THE UPPER PATTERN IS EXPECTED TO SHIFT APPROXIMATELY 5 DEGREES E TOMORROW AND BECOME MORE AMPLIFIED AS SHORTWAVE ENERGY CURRENTLY ON THE NW EDGE OF THE TROUGH ROUNDS ITS BASE AND TURNS THE TROUGH MORE NEUTRALLY TILTED. SOME OF THAT ENERGY WILL BE LEFT BEHIND BY THE TROUGH ON SUN AS IT SLOWLY MOVES EASTWARD. THIS WILL KEEP THE LONG-WAVE PATTERN SOMEWHAT STAGNANT INTO MON. AT THE SURFACE...1036 MB HIGH PRES NEAR 34N142W WITH A RIDGE EXTENDING SE INTO THE FORECAST AREA TO 15N110W DOMINATES THE SENSIBLE WEATHER OVER THE FORECAST AREA. THE ASCAT PASSES FROM 0508 AND 0648 UTC SHOW FRESH TO MODERATE TRADE WINDS W OF THE RIDGE AXIS AND NW TO N WINDS E OF THE RIDGE AXIS. SHIPS A8JX9...ZCDG7...NWS0009...AND WTEU ARE ALL WITHIN 150 NM OF THE COAST OF BAJA CALIFORNIA N OF 25N AND SHOW WINDS IN THE 25-30 KT RANGE THIS MORNING WITH SEAS OF 12-13 FT IN NW SWELL. 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 E OF THE ROCKIES AND SIERRA MADRE OCCIDENTAL. THE 0508 UTC ASCAT PASS ALSO SHOWED W TO NW WINDS TO 25 KT IN THE CENTRAL GULF OF CALIFORNIA INDUCED BY THIS GRADIENT. THE PATTERN WILL REMAIN RELATIVELY UNCHANGED THROUGH SAT MORNING...WITH WINDS EXPECTED TO DIMINISH IN THE GULF OF CALIFORNIA SAT AFTERNOON. THE PRES GRADIENT WILL SLOWLY RELAX THROUGH SUN 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 IMPINGES UPON IT FROM THE W SUN. TROPICS... A LOW TO MID LEVEL CYCLONIC GYRE LIES ALONG THE E EDGE OF THE ITCZ. UPPER LEVEL FLOW OVER THE ITCZ HERE CONTINUES TO BE DIFFLUENT BETWEEN A WEAK ANTICYCLONE NEAR THE NW COAST OF NICARAGUA AND 20-30 KT NE WINDS S OF 04N ON THE NW SIDE OF A LARGE ANTICYCLONE CENTERED OVER BRAZIL NEAR 05S55W. THE ANTICYCLONE TO THE N IS EXPECTED TO STRENGTHEN AND LIFT N INTO THE NW CARIBBEAN WHILE A NEW ANTICYCLONE PINCHES OFF NEAR 10S87W OVER THE WEEKEND...KEEPING WINDS DIFFLUENT OVER SE WATERS THROUGH THE FORECAST PERIOD. THEREFORE...EXPECT CONVECTION TO CONTINUE IN THIS MOISTURE RICH AREA ALONG THE ITCZ E OF 110W FOR THE FORESEEABLE FUTURE. FARTHER W...A SURFACE TROUGH EMBEDDED IN THE ITCZ ALONG 106W HAD SCATTERED MODERATE AND ISOLATED STRONG CONVECTION W OF ITS AXIS TO 115W THIS MORNING. THIS TROUGH LIES UNDER A WEAK ANTICYCLONE THAT IS EXPECTED TO LIFT NE AND MERGE WITH THE STRENGTHENING ANTICYCLONE OVER CENTRAL AMERICA. WINDS ALOFT SHOULD BECOME LESS CONDUCIVE FOR DEEP CONVECTION NEAR THIS TROUGH THROUGH THE WEEKEND. FINALLY...CROSS-EQUATORIAL SW SWELL WILL MOVE INTO THE AREA S OF 05N W OF 115W ON SUN MORNING. $$ SCHAUER