000 AXPZ20 KNHC 290318 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED APR 29 2009 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... ITCZ AXIS IS CENTERED ALONG...3N78W 6N86W 3N100W 3N110W 3N120W 1N130W 3N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS 85W-89W. ...DISCUSSION... A PROGRESSIVE PATTERN IS TAKING SHAPE ACROSS THE REGION MARKED BY HIGHLY AMPLIFIED FEATURES. THE FIRST IS A BROAD RIDGING AT ALL LEVELS OF THE ATMOSPHERE OVER THE CENTRAL PORTION OF THE AREA WITH A MEAN MID/UPPER RIDGE AXIS EXTENDING INTO THE AREA THROUGH 32N133W TO 24N126W TO 17N121W TO A STATIONARY ANTICYCLONE NEAR 9N119W. ANOTHER RIDGE EXTENDS FROM THE ANTICYCLONE NE TO 16N111W TO ACROSS CENTRAL MEXICO. MID/UPPER LEVEL TROUGHING IS TO THE NE OF THE RIDGE OVER THE WRN U.S. WITH AN AXIS ALONG 116W N OF 23N. A NEARLY STATIONARY MID/UPPER LEVEL TROUGH IS OVER THE FAR ERN PORTION OF THE AREA EXTENDING FROM SE MEXICO SW TO NEAR 13N100W WHERE A CUT-OFF UPPER LEVEL CYCLONIC IS DEVELOPING. BROKEN MID AND UPPER LEVEL CLOUDS ARE BEING CHANNELED NEWD ACROSS CENTRAL AMERICA E OF THE TROUGH WITH SMALL POCKETS OF SCATTERED SHOWERS AND TSTMS LIFTING NNE WITHIN 75 NM EITHER SIDE OF LINE FROM 11N94W TO GUATEMALA WHERE CONVECTION IS INCREASING WITH TIME. AN AREA OF MODERATE SUBSIDENCE IS SEEN W OF THE TROUGH TO NEAR 112W LIMITING CONVECTION THERE WITH ONLY ISOLATED SHOWERS AND TSTMS WITHIN 45 NM EITHER SIDE OF LINE FROM 10N99W TO10N106W. A JET STREAM BRANCH WITH MAXIMUM WINDS OF 50-70 KT ENTERS THE REGION AT 18N140W...AND CONTINUES NE TO 23N130W TO 25N119W TO ACROSS THE BASE OF THE TROUGH LOCATED NE OF THE RIDGE AND TO ACROSS CENTRAL BAJA CALIFORNIA AND NEWD TO ACROSS THE SW U.S. THE RIDGE IS FORECAST TO DAMPEN OUT SOME AS IT GETS NUDGED EWD TO OVER THE WRN U.S. WITHIN THE NEXT 2-3 DAYS BY A RATHER SHARP DEEP LAYER TROUGH W OF THE AREA PRESENTLY ALONG 148W. THE TROUGH IS FORECAST TO BE ALONG 140W BY THU. ITS REFLECTION WILL BE SEEN AS WEAKENING FRONTAL BOUNDARY THAT MOVES INTO THE FAR NW WATERS WED AND BECOMES DIFFUSE AS IT PULLS NE OF THE AREA. FOR THE TIME BEING...DEEP LAYER MOISTURE CONSISTING OF BROKEN MULTILAYERED CLOUDS WITH DEVELOPING SCATTERED SHOWERS AND ISOLATED TSTMS IS ADVECTING NEWD INTO THE FAR NW WATERS MAINLY AS A RESULT OF THE ABOVE JET STREAM ROUNDING THE BASE OF THE TROUGH AS BRINGING ADDITIONAL MOSITURE FROM THE DEEP TROPICAL PACIFIC NEWD ACROSS THE RIDGE. SOME AMPLIFICATION OF THE RIDGE IS EVIDENT AS THE JET ENERGY IS DRIVEN NE AHEAD OF THE TROUGH. A MID/UPPER LEVEL TROUGH EXTENDS FROM 9N136W SE TO A SMALL UPPER LEVEL CYCLONE NEAR 2N130W. WITH LIMITED AVAILABLE MOISTURE NO DEEP CONVECTION IS NOTED NEAR THE TROUGH BUT MAY DEVELOP OVER THE NEXT 48 HRS AS IF THE TROUGH MOVES NEAR THE SW SIDE OF THE UPPER LEVEL ANTICYCLONE NEAR 9N119W WHERE THE FLOW PATTERN IS DIFFLUENT. BROAD/MID UPPER LEVEL RIDGING COVERING THE WRN CARIBBEAN SEA ALSO EXTENDS W ACROSS CENTRAL AMERICA TO THE E OF THE MID/UPPER LEVEL TROUGH OVER THE ERN PORTION OF THE AREA. AT THE SURFACE...HIGH PRES OF 1026 MB ALONG THE NRN BOUNDARY OF THE AREA NEAR 32N130W EXTENDS A RIDGE SE TO 24N121W TO 18N110W. AS THE TROUGH W OF THE AREA ADVANCES EWD THROUGH THE NEXT 48 HRS...THE RIDGE WILL ALSO SLIDE E AS WHILE LOW PRES DEEPENS OVER THE PLAINS INTO NRN MEXICO. THIS WILL ALLOW FOR THE PRES GRADIENT TO INCREASE OVER THE NE PART OF THE AREA INCREASING THE NW WINDS ALONG THE BAJA CALIFORNIA COAST REACHING W TO NEAR 121W. SE-S WINDS OF 20 KT E OF THE FRONTAL BOUNDARY WILL INCREASE TO 20-25 KT TO WITHIN 180 NM E OF THE BOUNDARY...THEN DIMINISH TO S-SW TO 20 KT IN 48 HRS. A WEAK TROUGH MOVING W 15 KT IS ALONG 135W FROM 9N-15N. GAP WINDS...NE WINDS OF 20-25 KT THROUGH THE GULF OF PAPAGAYO ARE EXPECTED TO CHANGE LITTLE IN 24 HRS...THEN DIMINISH TO 20 KT IN 36 HRS AND TO LESS THAN 20 KT IN 48 HRS. $$ AGUIRRE