000 AXPZ20 KNHC 221005 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI MAR 22 2013 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS ACROSS THE GULF OF PANAMA SW TO 08N82W...AND CONTINUES TO 02N100W TO 01N118W WHERE LOW LEVEL WINDS AND PARTIAL ASCAT/OSCAT DATA INDICATE THAT IT TRANSITIONS TO AND ITCZ AXIS TO BELOW THE EQUATOR AT 127W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE TROUGH BETWEEN 83W-86W...AND ALSO WITHIN 120 NM N OF THE AXIS BETWEEN 88W-90W. ...DISCUSSION... ALOFT...A LONGWAVE TROUGH EXTENDS FROM NW CONUS SSW THROUGH 32N120W TO AN UPPER LOW RETROGRADING SW AT 25N128W. HIGHLY AMPLIFIED RIDGING COVERS THE FAR W AND NW PORTIONS OF THE AREA. ATMOSPHERIC MOISTURE REMAINS VERY LIMITED AS ABUNDANT DEEP MOISTURE W OF THE AREA OVER THE CENTRAL PACIFIC IS SHUNTED NEWD ON THE BACK SIDE OF THE RIDGE TO WELL N OF THE REGION. SATELLITE WATER IMAGERY SHOWS STRONG SUBSIDENCE PREVAILING OVER JUST ABOUT THE ENTIRE DISCUSSION AREA. THE UPPER LOW WILL MOVE SW THROUGH TONIGHT....THEN BE FORCED ENE TOWARD CENTRAL BAJA CALIFORNIA THROUGH SUN EVENING BY THE RIDGE TO ITS W AS IT IS DISPLACED EWD BY A RATHER VIGOROUS TROUGH W OF IT. THE LOW MAY BRIEFLY SPAWN A WEAK SURFACE LOW OR TROUGH BEFORE IT EXITS THE AREA...HOWEVER ANY SUCH FEATURE SHOULD BE RATHER WEAK. MODEST RIDGING AT THE MID/UPPER LEVELS IS PRESENT BETWEEN SRN BAJA CALIFORNIA AND 11N BETWEEN 107W-125W. A SHORTWAVE TROUGH IS E OF THIS RIDGE EXTENDING FROM CENTRAL MEXICO SW TO NEAR 11N107W. BOTH OF THESE FEATURES ARE MOVING EWD...AND WILL MOVE ACROSS CENTRAL AND SRN MEXICO LATE TODAY AND THIS EVENING. ONLY MOISTURE IN THE UPPER LEVELS IN THE FORM OF MOSTLY BROKEN HIGH CLOUDS IS NOTED TO THE E OF THE TROUGH. BROAD SCALE RIDGING IS EVIDENT SE OF THESE FEATURES OVER THE FAR SE PORTION OF THE AREA WHICH ENCOMPASSES THE AREA ACROSS THE MONSOON TROUGH. ACTIVE CLUSTERS OF CONVECTION AS DESCRIBED ABOVE UNDER ITCZ/MONSOON TROUGH ARE OCCURRING OVER THIS PORTION OF THE AREA. THIS ACTIVITY IS EXPECTED TO INTERMITENTLY CONTINUE THROUGH THE NEXT 48 HRS. AT THE SURFACE...A STRONG 1034 MB HIGH CENTER WELL N OF THE AREA AT 41N134W EXTENDS A RIDGE SSW THROUGH 32N138W AND WELL W OF THE AREA TOWARDS THE HAWAIIAN ISLANDS. A DISSIPATING TROUGH IS ALONG 20N133W 16N136W. THE PRES GRADIENT THROUGHOUT IS LIGHT...WITH THE EXCEPTION BEING THE NE PORTION WHERE A TIGHT GRADEINT THERE BETWEEN THE RIDGE AND TROUGHING ALONG CALIFORNIA AND NRN BAJA CALIFORNIA HAS INDUCED GALE CONDITIONS N OF THE AREA NEAR CENTRAL CALIFORNIA...AND NW-N WINDS OF 20-25 KT S TO 28N AND E OF 132W. SEAS WITHIN THIS AREA ARE 8-10 FT. THE 1034 MB HIGH IS FORECAST TO SHIFT E AND WEAKEN OVER THE NEXT 48 HRS ALLOWING FOR THE TIGHT GRADIENT OVER THE NE PORTION TO SLACKEN. THIS WILL RESULT IN DIMINISHING WINDS FROM 20-25 KT TO 20 KT OR LESS BY 48 HRS N OF 25N BETWEEN 115W-135W WITH SEAS 8-10 FT IN A NW SWELL. ITS FROM W OF 110W...A STRONG HIGH PRESSURE 1034 MB IS CENTERED WELL N OF THE AREA NEAR 41N135W WITH RIDGE EXTENDING SE TO NEAR 12N110W. THE PRESSURE GRADIENT BETWEEN THE HIGH AND THE ITCZ OVER WESTERN WATERS IS WEAK AND IS SUPPORTING MAINLY MODERATE TRADES. THE PRESSURE GRADIENT HAS TIGHTENED BETWEEN THE RIDGE AND LOWER PRESSURE OVER MEXICO AND THE SW UNITED STATES. THIS IS RESULTING IN A FRESH TO STRONG N-NW BREEZE OVER THE NE FORECAST WATERS OFF BAJA CALIFORNIA NORTE...WITH GALE CONDITIONS DEVELOPING N OF THE FORECAST REGION. THIS WEATHER PATTERN WILL PERSIST OVER THE NEXT 24 HOURS WITH WINDS DIMINISHING BELOW 20 KT OVER THE N-CENTRAL WATERS BY 48 HOURS AS HIGH PRES WEAKENS. A SURGE OF LONG-PERIOD NW SWELL WILL REACH THE FAR NW WATERS LATER TONIGHT...WITH COMBINED SEAS AROUND 8 FT MOVING INTO THE AREA. THIS SWELL EVENT WILL ALSO OVERLAP WITH THE AREA OF N-NW SWELL OVER THE NE WATERS OVERNIGHT FRI NIGHT. IN ADDITION...A NEW CROSS-EQUATORIAL SW SWELL TRAIN WITH PERIODS IN EXCESS OF 20 SECONDS WILL PROPAGATE NORTHEASTWARD REACHING THE COAST OF MUCH OF CENTRAL AMERICA AND MAINLAND MEXICO BY FRI AFTERNOON AND BAJA CALIFORNIA OVERNIGHT FRI NIGHT. $$ AGUIRRE