000 AXPZ20 KNHC 132149 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT NOV 13 2010 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 2100 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 06N89W TO LOW PRES NEAR 11N109W TO 09N120W TO 10N127W TO 10N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM OF THE LOW IN THE E AND SE QUADRANTS. ...DISCUSSION... AN UPPER LEVEL TROUGH EXTENDS FROM NEAR 32N117W TO NEAR 25N130W WITH AN ASSOCIATED SUBTROPICAL JET WITH CORE SPEEDS OF 70 TO 90 KT EXTENDING OVER THE BAJA CALIFORNIA PENINSULA TO ACROSS NORTHERN MEXICO. DRY AND STABLE AIR UNDER MODERATE TO STRONG SUBSIDENCE IS NOTED ACROSS THE AREA N OF 24N. AN UPPER LEVEL RIDGE EXTENDS FROM THE SW CARIBBEAN THROUGH CENTRAL AMERICA ALL THE WAY TO NEAR 11N128W. SW FLOW ALOFT S OF THE SUBTROPICAL JET AND N OF THE UPPER RIDGE IS ADVECTING MID TO UPPER LEVEL MOISTURE FROM THE ITCZ TO ACROSS CENTRAL MEXICO. AT THE SURFACE...STRONG 1041 MB HIGH PRES IS CENTERED WELL N OF THE AREA NEAR 38N136W WITH A RIDGE AXIS EXTENDING INTO THE AREA NEAR 32N136W AND CONTINUING SE TO NEAR 17N110W. FRESH TO STRONG TRADES EXIST N OF 12N AND W OF 122W WITH RESULTANT SEAS OF 8 TO 12 FT. THE AREA OF TRADES WILL SHRINK TO N OF 20N AND W OF 126W ON MON AS THE RIDGE RETRACTS TO THE N. 1012 MB LOW PRES IS EMBEDDED IN THE ITCZ NEAR 11N109W. A 1620 UTC ASCAT PASS CAPTURED 20 KT WINDS WITHIN 150 NM OF THE LOW IN THE SE SEMICIRCLE ALONG WITH 8 FT SEAS. THESE WINDS WILL PERSIST THROUGH MON AS THE LOW MOVES W AROUND 5 KT. ASSOCIATED CONVECTION IS AS DESCRIBED ABOVE IN THE ITCZ SECTION. NO TROPICAL DEVELOPMENT OF THIS LOW IS ANTICIPATED. WEAK 1012 MB LOW PRES IS POSITIONED NEAR 07N87W WITH SCATTERED MODERATE TO STRONG CONVECTION OCCURRING WITHIN 180 NM OF THE LOW IN THE W QUADRANT. THIS LOW WILL RETROGRADE TO THE NE TOWARD PANAMA DUE TO SOUTHERLY FLOW INCREASING. THIS SOUTHERLY FLOW IS CURRENTLY 20 KT IN THE FAR E PORTION OF THE AREA ROUGHLY FROM 03N TO 08N BETWEEN 80W AND 86W AS INDICATED BY A 1440 UTC ASCAT PASS AND AS REPORTED BY SHIPS ZCDG4 AND 9HJD9 OFF OF THE COAST OF WESTERN PANAMA. THESE CONDITIONS WILL REMAIN IN PLACE THROUGH MON AS LOW PRES ATTEMPTS TO DEVELOP IN THE SW CARIBBEAN SEA JUST N OF THE ISTHMUS OF PANAMA. LONG PERIOD NW SWELL CONTINUES TO MIX WITH FRESH NE SEAS IN THE AREA OF TRADES DESCRIBED ABOVE. A NEW SET OF N TO NE SWELL GENERATED BY GALE CONDITIONS OFF THE U.S. CALIFORNIA COAST WILL PROPAGATE DOWN S OF 30N TONIGHT WITH SEAS BUILDING TO 15 FT ALONG AND N OF 30N BY 18 UTC SUN. THIS SWELL WILL PERSIST THROUGH MON. CROSS-EQUATORIAL SW SWELL WITH SEAS TO 8 FT WILL MOVE N OF THE EQUATOR INTO THE S CENTRAL PORTION OF THE AREA ON MON. GULF OF CALIFORNIA... A TIGHT PRES GRADIENT REMAINS OVER THE GULF OF CALIFORNIA REGION BETWEEN A RIDGE W OF THE BAJA CALIFORNIA PENINSULA AND TROUGHING JUST INLAND OF THE E PORTION OF THE GULF OF CALIFORNIA. AN EARLIER ASCAT PASS CAPTURED 20 KT NW TO N WINDS IN THE NORTHERN PORTION OF THE GULF WITH LAND BASED OBSERVATIONS AT LORETO MEXICO IN BAJA CALIFORNIA SUR NEAR 26N REPORTING 20 KT. THE PRES GRADIENT WILL WEAKEN AS THE TROUGHING DISSIPATES BY 18 UTC SUN. GAP WINDS... A 2010 UTC ASCAT PASS INDICATED 20 KT NORTHERLY WINDS IN THE GULF OF TEHUANTEPEC N OF 15.5N BETWEEN 94W AND 96W AS WAS PREDICTED BY THE GFS AND ECMWF. MEANWHILE LAND BASED OBSERVATIONS AT IXTEPEC MEXICO CONTINUE TO REPORT 20 TO 25 KT N WINDS. THESE WINDS IN THE GULF OF TEHUANTEPEC ARE EXPECTED TO DIMINISH TO LESS THAN 20 KT BY 18 UTC SUN. $$ LEWITSKY