000 AXPZ20 KNHC 012341 AAA TWDEP TROPICAL WEATHER DISCUSSION...UPDATED NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2340 UTC FRI MAY 01 2009 ...UPDATED CONVECTIVE ACTIVITY ASSOCIATED WITH MID/UPPER TROUGH OVER THE ERN PORTION OF AREA.... 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 2315 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N78W 4N98W 3N111W 4N120W 3N130W 4N140W. ISOLATED MODERATE CONVECTION IS S OF THE AXIS WITHIN 45 NM OF 4N93W...WITHIN 30 NM OF 4N83W...5N86W AND 5N89W. ...DISCUSSION... HIGHLY AMPLIFIED FEATURES AREA ACROSS THE DISCUSSION AREA. THE FIRST BEING BROAD MID AND UPPER RIDGING STRETCHING FROM FROM NW MEXICO TO THE CENTRAL PORTION OF THE AREA WITH A MEAN AXIS GENERALLY ALONG 32N107W SW TO ACROSS SRN BAJA TO 19N116W TO A WELL ANCHORED ANTICYCLONE NEAR 10N120W. A WEAK LOW TO MID LEVEL INVERTED TROUGH EXTENDS FROM 8N134W TO 2N131W. UPPER LEVEL DIFFLUENCE BETWEEN THE TROUGH AND THE ANTICYCLONE MAY ALLOW FOR CONVECTION TO INCREASE ALONG OR NEAR THE ITCZ BETWEEN 132W-135W. THE TROUGH IS EXPECTED TO LOSE ITS IDENTITY OVER THE NEXT 24 HRS AS THE DEEP LAYER TROUGH DESCRIBED BELOW TAKES PRECEDENCE. A NEARLY STATIONARY MID/UPPER LEVEL TROUGH IS OVER THE FAR ERN PORTION OF THE AREA EXTENDING FROM SE MEXICO SW TO 10N103W TO 1N108W. A SMALL UPPER LEVEL CYCLONIC CIRCULATION MOVING W IS EMBEDDED IN THE TROUGH ALONG THE COAST OF MEXICO NEAR 16N96W. BROKEN MID AND UPPER LEVEL CLOUDS ARE BEING CHANNELED NEWD ACROSS CENTRAL AMERICA DRIVEN BY A JET STREAM FOUND TO THE E OF THE TROUGH ALONG 7N105W TO 11N98W NE TO ACROSS SE MEXICO AND WRN GUATEMALA. SCATTERED SHOWERS AND TSTMS ARE ALONG THE TROUGH AXIS AND JUST N OF THE ITCZ FROM 6N-9N BETWEEN 90W-97W. SIMILAR ACTIVITY IS INCREASING OVER SE MEXICO E OF 98W TO OVER GUATEMALA AND NW HONDURAS FURTHER ENHANCED BY LATE DAYTIME HEATING. THIS CONVECTIVE ACTIVITY IS FORECAST TO CONTINUE THROUGH AT LEAST THE NEXT COUPLE OF DAYS AS THE LOW AND TROUGH REMAIN ABOUT STATIONARY. MEANWHILE...THE RIDGE WILL GET NUDGED E OF THE AREA THROUGH SAT BY A RATHER SHARP DEEP LAYER TROUGH PRESENTLY ALONG 32N125W TO 25N127W TO 18N134W TO 12.5N140W. A VERY WELL PRONOUNCED NRN STREAM JET STREAM BRANCH WITH MAXIMUM WINDS OF 70-120 KT SHARPLY DIVES SEWD BRUSHING THE FAR NRN BOUNDARY OF THE AREA. THE TROUGH WILL QUICKLY LIFT NE AND SHEAR OUT OVER THE FAR NE PART OF THE AREA AND ACROSS NRN BAJA CALIFORNIA AND SRN CALIFORNIA ON SAT. AT THE PRESENT TIME...DEEP LAYER MOISTURE CONSISTING OF BROKEN MULTILAYERED CLOUDS WITH SCATTERED SHOWERS AND ISOLATED TSTMS IS ADVECTING NEWD ACROSS THE CENTRAL AND NE PORTIONS OF THE AREA WITHIN 160 NM E OF THE TROUGH. BROAD/MID UPPER LEVEL RIDGING IS LOCATED TO THE E OF THE TROUGH WITH A MEAN AXIS STRETCHING NW TO SE ALONG THE WRN CARIBBEAN SEA. AT THE SURFACE...HIGH PRES OF 1021 MB IS NEAR 25.5N127W WITH A RIDGE SE TO 16N112W. AS THE TROUGH W OF THE AREA ADVANCES EWD THROUGH THE NEXT 48 HRS...THE RIDGE WILL ALSO SLIDE E 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 NW WINDS ALONG THE BAJA CALIFORNIA COAST TO THE RANGE OF 20-25 KT IN ABOUT 48 HRS...WITH SEAS BUILDING 8-10 FT IN NW SWELL. A WEAKENING FRONTAL TROUGH IS ANALYZED FROM 30N134W TO 26N140W. S-SW WINDS OF 20-25 KT WHERE OBSERVED WITHIN 180 NM E OF THE TROUGH N OF 28N IN A QUIKSCAT PASS FROM JUST PAST 1430 UTC THIS MORNING. THE TROUGH IS FORECAST TO DISSIPATE WITHIN THE NEXT 24 HRS ALLOWING FOR A WEAKER GRADIENT TO ITS E TO SUPPORT WEAKER SW WINDS TO 20 KT. HOWEVER...A STRONGER COLD FRONT SEEN TO THE NW OF THE AREA IN FASTER NRN STREAM OF W TO NW FLOW WILL QUICKLY ADVANCE EWD DURING THE NEXT 48 HRS. IN ITS WAKE...A LARGE NW SWELL TRAIN CONSISTING OF SEA HEIGHTS IN THE 8-11 FT RANGE WITH WAVE PERIODS OF 11-13 SECONDS WILL BEGIN TO INVADE THE FAR NW WATERS SAT NIGHT THROUGH SUN PER LATEST WAVE MODEL GUIDANCE. A WEAK TROUGH MOVING W 10-15 KT EXTENDS FROM 2N139W TO 8N136W TO 12N133W. ISOLATED WEAK CONVECTION IS W OF THE TROUGH FROM 4N-7N MAINLY TIED TO THE ITCZ...WITH STRONGER CONVECTION JUST W OF THE AREA. $$ AGUIRRE