000 AXPZ20 KNHC 100928 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU MAR 10 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0800 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 02N86W TO 04N104W TO 04N118W TO 03N125W TO 04N140W. SCATTERED MODERATE CONVECTION LIES BETWEEN 120 NM AND 180 NM N OF THE ITCZ AXIS W OF 136W. ...DISCUSSION... RIDGING ASSOCIATED WITH THE STATIONARY ANTICYCLONE NEAR 06N103W MARKS THE AREA S OF 17N BETWEEN 95W AND 115W. SUBSIDENCE IS PREVALENT THERE. TO THE E OF THE ANTICYCLONE LIES A WEAK UPPER TROUGH FOLLOWED BY A VAST UPPER RIDGE THAT SPANS ACROSS MUCH OF THE TROPICAL ATLC AND NORTHERN SOUTH AMERICA. DIFFLUENT FLOW BETWEEN THE SW EDGE OF THIS RIDGE AND THE WEAK TROUGH IS ENHANCING THE SCATTERED MODERATE CONVECTION WITHIN 90 NM OF THE SOUTH AMERICAN COAST FROM 04N TO 07N. A NEGATIVELY TILTED UPPER TROUGH LIES TO THE W OF THE AFOREMENTIONED ANTICYCLONE LIES FROM 14N128W TO 00N120W. THIS TROUGH IS EXPECTED WEAKEN AND SHIFT NE TODAY AS THE RIDGING TO ITS W AMPLIFIES AND CUTS OFF ANOTHER ANTICYCLONE NEAR 10N125W THIS AFTERNOON. CURRENTLY...DIFFLUENT FLOW ALOFT LIES NEAR THE ITCZ W OF THIS RIDGING AND IS ENHANCING CONVECTION ALONG THE W PORTION OF THE ITCZ. THIS CONVECTION IS DESCRIBED IN THE ITCZ SECTION ABOVE. A WEAK COLD FRONT HAS ENTERED THE NW PORTION OF THE FORECAST AREA FROM 32N136W TO 29N140W. THE UPPER SUPPORT FOR THIS FRONT WILL RACE EASTWARD INTO THE U.S. W COAST TODAY WHILE THE PORTION OVER THE FORECAST AREA WEAKENS AS IT IS FORCED AGAINST THE PERSISTENT UPPER RIDGE OVER THE NE PORTION OF THE FORECAST AREA INCLUDING NW MEXICO. AN INCREASED PRES GRADIENT BETWEEN HIGH PRES BEHIND THIS FRONT AND LOWER PRES E OF THE ROCKIES AND SIERRA MADRE OCCIDENTAL ASSOCIATED WITH THE FRONT WILL BRING NW WINDS TO 20 KT OFF THE COAST OF BAJA CALIFORNIA SUR OVERNIGHT FRI NIGHT. WINDS ARE CURRENTLY BELOW ADVISORY CRITERIA NEAR THE FRONT...BUT NW SWELL BEHIND THE FRONT HAS BROUGHT SEAS TO 9 FT THIS MORNING AND THEY ARE EXPECTED TO REACH AS HIGH AS 14 FT OVERNIGHT TONIGHT AS THE SWELL TRAIN PROCEEDS SOUTHEASTWARD. FRESH TRADE WINDS CURRENTLY LIE FROM 07N TO 17N W OF 124W. TRADE WINDS ARE EXPECTED TO REMAIN FRESH AS THEY SHRINK SOUTHWARD AND EXPAND EASTWARD JUST N OF THE ITCZ IN RESPONSE TO THE RIDGE AXIS...CURRENTLY EXTENDING FROM 1025 MB HIGH PRES NEAR 29N129W TO 12N98W...SHIFTING EASTWARD AHEAD OF THE WEAK FRONT OVER NW WATERS. GAP WINDS... GULF OF CALIFORNIA...SHIPS PBKH AND C6FR3 IN THE MOUTH OF THE GULF OF CALIFORNIA HAVE BEEN REPORTING WINDS AT ADVISORY CRITERIA OVER THE PAST SEVERAL HOURS. THESE WINDS ARE FORECAST TO DIMINISH LATER THIS MORNING. GULF OF TEHUANTEPEC...A STRONG COLD FRONT PASSING THROUGH THE WESTERN GULF OF MEXICO THIS MORNING WILL MOVE THROUGH THE ISTHMUS OF TEHUANTEPEC AROUND SUNRISE. WINDS FUNNELING THROUGH THE CHIVELAS PASS INTO THE GULF OF TEHUANTEPEC WILL QUICKLY INCREASE TO GALE FORCE THIS MORNING AND REACH 45 KT BY THIS EVENING WITH SEAS AS HIGH AS 20 FT. WINDS ARE EXPECTED TO DIMINISH BELOW GALE FORCE BY FRI EVENING AS THE HIGH PRES OVER THE GULF BEHIND THE COLD FRONT BECOMES DISPLACED EASTWARD BY THE NEXT FRONT ENTERING THE SOUTHERN PLAINS. GULF OF PAPAGAYO...AS THE GULF OF MEXICO COLD FRONT CONTINUES TO MOVE SOUTHEASTWARD INTO THE WESTERN CARIBBEAN...WINDS WILL FUNNEL THROUGH SOUTHERN NICARAGUA AND NORTHERN COSTA RICA THAT WILL PRODUCE FRESH NE WINDS ACROSS THE GULF OF PAPAGAYO AND DOWNWIND TO 88W BY FRI MORNING. $$ SCHAUER