000 AXPZ20 KNHC 110348 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI MAR 11 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0200 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS ANALYZED FROM 04N86W TO 02N91W TO 06N120W TO 07N123W TO 03N135W TO 03N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 90 NM OF THE AXIS BETWEEN 88W AND 94W...AND WITHIN 90 NM N OF THE AXIS W OF 131W. ...DISCUSSION... IN THE UPPER LEVELS...A BROAD FLAT RIDGING REMAINS ANCHORED ACROSS THE TROPICAL EPAC...CENTERED ON AN UPPER ANTICYCLONE NEAR 04N108W...WITH RIDGE N TO 20N BETWEEN 95W AND 120W. UPPER RIDGING IS ALSO OCCURRING OVER THE ITCZ BETWEEN 125W AND 145W IN RESPONSE TO DIVERGENT ALOFT INDUCED BY PULSING DEEP ITCZ CONVECTION. AN ENERGETIC AND PROGRESSIVE SWLY UPPER LEVEL FLOW OTHERWISE GENERALLY PREVAILS TO THE W AND NW OF THE RIDGE AND ITCZ...AND IS TRANSPORTING ABUNDANT MOISTURE FROM THE CENTRAL TROPICAL PACIFIC TO THE CREST AND OVER THE TOP OF THE RIDGE AND INTO BAJA CALIFORNIA AND NW MEXICO. A FEW SUBTLE SHORTWAVES WERE NOTED IN THIS SWLY FLOW ALOFT...WITH THE MOST SIGNIFICANT N OF 17N ALONG 129W...AND A SHORTWAVE RIDGE DIRECTLY DOWNSTREAM MOVING OVER THE FLAT ANCHORING RIDGE AND WAS N OF 22N ALONG 118W. SUBSIDENCE DOMINATES THE NE QUADRANT OF THE BROAD UPPER RIDGE AND EXTENDS NE INTO SWRN MEXICO AND E INTO THE TROPICAL EPAC N OF THE ITCZ TO 86W. UPSTREAM...A STRONG AND DYNAMIC UPPER TROUGH WAS SWEEPING ACROSS THE N CENTRAL PACIFIC AND WILL APPROACH NW PORTIONS OF THE AREA WITHIN 48 HOURS...USHERING A FRONTAL SYSTEM AND VERY DEEP SURFACE LOW PRES SYSTEM INTO THE NE PACIFIC. LARGE NW SWELL ASSOCIATED WITH THIS SYSTEM WILL MOVE INTO N PORTIONS OF THE AREA SUN THROUGH MON. AT THE SURFACE...A WEAK AND NEARLY STATIONARY FRONT WAS DRIFTING VERY SLOWLY E ACROSS NW PORTION OF THE FORECAST AREA FROM 30N135W TO 28N140W. THE UPPER SUPPORT FOR THIS FRONT HAS RACED EAST NORTHEASTWARD INTO THE U.S. W COAST...LEAVING MID LEVEL TROUGHING ACROSS THE NE CORNER OF THE AREA WITH NO CURRENT FORCING TO MOVE THE FRONT SIGNIFICANTLY FORWARD...AS IT IS FORCED AGAINST THE PERSISTENT UPPER RIDGE AND AN ASSOCIATED 1025 MB SURFACE HIGH OVER THE REMAINING N PORTIONS OF THE FORECAST AREA. AS THIS NEXT MAJOR UPSTREAM UPPER TROUGH MOVES CLOSER TO THE AREA...THE SURFACE HIGH WILL BE NUDGED E AND SE...AND ACT TO INCREASE THE PRES GRADIENT BETWEEN THE HIGH PRES AND LOWER PRES E OF THE ROCKIES AND SIERRA MADRE OCCIDENTALES. THIS WILL INDUCE NW WINDS TO 20 KT OFF THE COAST OF BAJA CALIFORNIA OVERNIGHT AND STRENGTHEN THROUGH SAT MORNING. NW SWELL BEHIND THIS CURRENT STALLED FRONT ARE MOVING SE AND BEYOND THE FRONT AND HAVE RAISED SEAS 10 TO 14 FT THIS EVENING ACROSS FAR NW PORTIONS. THE SHIFTING SURFACE HIGH HAS WEAKENED THE PRES GRADIENT N OF THE ITCZ...WHICH IS LIMITING FRESH TRADE WINDS CURRENTLY FROM FROM 06N TO 16N W OF 135W. THIS AREA OF 20 KT TRADE WINDS IS EXPECTED TO SHRINK AND SHIFT WESTWARD FOR THE NEXT 48 HOURS THEN BECOME REINVIGORATED EARLY MON AS THE NEXT FRONT APPROACHES FROM THE NW. GAP WINDS... GULF OF TEHUANTEPEC...A STRONG COLD FRONT SWEEPING THROUGH THE WESTERN GULF OF MEXICO TODAY HAS REACHED THE YUCATAN PENINSULA WITH COOL AIR CONTINUING TO BLAST THROUGH THE ISTHMUS OF TEHUANTEPEC. WINDS FUNNELING THROUGH THE CHIVELAS PASS AND ACROSS THE GULF OF TEHUANTEPEC INCREASED TO GALE FORCE LATE THIS MORNING AND WERE ESTIMATED AT 45 KT THIS EVENING BASED ON SURFACE OBSERVATIONS ON BOTH SIDES OF THE ISTHMUS. PEAK SEAS WITHIN THIS PLUME OF NORTHERLY WINDS HAVE BUILT AS HIGH AS 18 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 AND PRODUCE FRESH NE WINDS ACROSS THE GULF OF PAPAGAYO AND DOWNWIND TO 88W BY MORNING AND LAST AT LEAST 24 MORE HOURS. $$ STRIPLING