000 AXPZ20 KNHC 102129 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON SEP 10 2012 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2015 UTC. ...SPECIAL FEATURE... A BROAD AREA OF LOW PRESSURE EMBEDDED ON THE MONSOON TROUGH NEAR 12N98W IS MOVING NE AROUND 10 KT. EASTERLY WINDS TO 25 KT ARE WITHIN 210 NM OF THE CENTER OVER THE N AND NE QUADRANTS AS SEEN BY SHIP MCZN2 AS WELL AS THE 1622 UTC ASCAT PASS. THIS LOW LIES IN AN AREA OF SW SWELL. THE CONVECTION NEAR THE LOW REMAINS DISORGANIZED THIS AFTERNOON...BUT ENVIRONMENTAL CONDITIONS REMAIN CONDUCIVE FOR DEVELOPMENT OVER THE NEXT COUPLE OF DAYS. THIS SYSTEM COULD BECOME A TROPICAL CYCLONE. THIS LOW PRES SYSTEM IS CURRENTLY FORECAST TO GRADUALLY DEEPEN AND WINDS INCREASE TO 30 KT AS IT CONTINUES NORTHEASTWARD THROUGH WED AFTERNOON. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N78W TO 09N88W TO 13N95W TO LOW PRES NEAR 12N98W TO 14N110W TO 09N130W. THE ITCZ AXIS WAS ANALYZED FROM 09N130W TO 09N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 240 NM S OF THE AXIS BETWEEN 78W AND 82W AS WELL AS WITHIN 180 NM N OF THE AXIS BETWEEN 94W AND 110W AND WITHIN 180 NM S OF THE AXIS BETWEEN 98W AND 109W. SCATTERED MODERATE CONVECTION WAS ALSO FOUND WITHIN 90 NM N AND 120 NM S OF THE AXIS BETWEEN 112W AND 122W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 120 NM N OF THE AXIS W OF 128W AND WITHIN 120 NM S OF THE AXIS BETWEEN 125W AND 130W. ...DISCUSSION... A DEEP LAYERED LOW LIES OVER BAJA CALIFORNIA NORTE. SOUTHERLY FLOW ON THE EASTERN SIDE OF THIS LOW IS PUMPING MOISTURE NORTHWARD ALONG THE W COAST OF MEXICO INTO THE GULF OF CALIFORNIA. SCATTERED MODERATE CONVECTION WAS NEAR THE LOW WITHIN 45 NM OF THE GULF OF CALIFORNIA COAST N OF 31N AND WITHIN 45 NM OF THE E COAST OF BAJA CALIFORNIA FROM 28N TO 30N. THIS LOW IS FORECAST TO BE SLOWLY BUMPED NORTHEASTWARD BY A SHORTWAVE TROUGH CURRENTLY OFF THE CENTRAL CALIFORNIA COAST AS IT MOVES INLAND. AN UPPER LEVEL ANTICYCLONE NEAR 21N107W EXTENDS A RIDGE AXIS SOUTHEASTWARD ALONG THE COAST TO 10N88W. A 30-50 KT EASTERLY JET LIES SE OF THE ANTICYCLONE S OF 07N W OF 105W. THIS SHEAR IS INHIBITING THE DEVELOPMENT OF DEEP CONVECTION...BUT THE BROAD AREA OF DIFFLUENCE ALOFT BETWEEN THIS JET AND THE RIDGE AXIS TO ITS NE IS ENHANCING THE SCATTERED MODERATE CONVECTION ALONG THE MONSOON TROUGH DESCRIBED IN THE SECTION ABOVE. BROAD UPPER DIFFLUENCE BETWEEN LIGHT EASTERLY WINDS S OF A SECOND ANTICYCLONE ALOFT NEAR 15N140W AND THE MORE NORTHEASTERLY DIRECTED UPPER JET OVER W WATERS IS ALSO ENHANCING CONVECTION NEAR THE ITCZ. THIS SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS ALSO DESCRIBED IN THE SECTION ABOVE. THE 1030 MB SUBTROPICAL HIGH WAS ANALYZED NEAR 36N150W. THE HIGH IS FORECAST TO SHIFT NORTHEASTWARD OVER THE NEXT FEW DAYS BEHIND A COLD FRONT THAT IS CURRENTLY MOVING INTO THE WESTERN UNITED STATES. THE 1804 UTC AND 1944 ASCAT PASSES SHOWED THE STRONG TRADE WINDS THAT WERE OVER W WATERS EARLIER TODAY HAVE MOVED W OF THE FORECAST AREA. THE RESIDUAL SWELL FROM THE TRADE WINDS IS EXPECTED TO SUBSIDE BELOW ADVISORY CRITERIA TONIGHT. HIGH PRES BUILDING SOUTHWARD OVER THE GULF OF MEXICO BEHIND A COLD FRONT AND THE NORTHWARD MIGRATION OF THE MONSOON TROUGH NEAR THE LOW PRES SYSTEM DISCUSSED IN THE SPECIAL FEATURES SECTION WILL INCREASE THE PRES GRADIENT OVER CENTRAL AMERICA. FRESH NE TO E WINDS ARE EXPECTED DOWNWIND OF THE GULF OF PAPAGAYO BEGINNING TUE MORNING AS A RESULT. WINDS MAY BRIEFLY PULSE TO A STRONG BREEZE IN THE EARLY MORNING HOURS WED WITH THE ASSISTANCE OF DRAINAGE FLOW OFF THE LAND. ON WED...A NEW BATCH OF SW SWELL WILL CROSS THE EQUATOR. SEAS TO 8 FT ARE EXPECTED S OF 03N BETWEEN 110W AND 130W BY WED AFTERNOON. $$ SCHAUER