000 AXPZ20 KNHC 120939 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT MAR 12 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 0900 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 08N78W TO 02N95W TO 06N120W TO 05N130W TO 04N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 85W AND 87W AND ALSO WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 90W AND 94W. SIMILAR CONVECTION IS NOTED WITHIN 180 NM N OF THE AXIS BETWEEN 117W AND 130W AND ALSO WITHIN 120 NM S OF THE AXIS BETWEEN 120W AND 125W. ...DISCUSSION... A BROAD AND RELATIVELY FLAT TROPICAL UPPER RIDGE PERSISTS OVER THE MAJORITY OF THE AREA FROM JUST N OF THE EQUATOR TO NEAR 21N BETWEEN 95W AND 140W. UPPER LEVEL DIVERGENCE WITH THE W PORTIONS OF THE RIDGE IS INDUCING DEEP CONVECTION ALONG THE ITCZ AS DESCRIBED ABOVE. AN EQUATORIAL UPPER TROUGH IS NOTED MEANDERING ALONG THE EQUATOR E OF 136W...ANCHORED ON AN UPPER CYCLONIC VORTEX JUST S OF THE ITCZ NEAR 02N130W. SUBSIDENCE DOMINATES THE AREA N OF 10N E OF 110W. OTHERWISE AN ENERGETIC AND PROGRESSIVE W-SW FLOW PREVAILING ALOFT NW OF THE RIDGING AND ITCZ CONTINUES TO TRANSPORT ABUNDANT MOISTURE FROM THE CENTRAL TROPICAL PACIFIC S OF THE HAWAIIAN ISLANDS TO THE CREST AND OVER THE TOP OF THE RIDGE TO ACROSS BAJA CALIFORNIA...NW MEXICO AND THE SW CONUS. WEAK SHORTWAVE TROUGHS ARE NOTED IN THIS W-SW FLOW WITH LITTLE IMPACT GENERATED BY THEM. UPSTREAM...A STRONG AND DYNAMIC UPPER TROUGH IS ENTERING THE NE PACIFIC REACHING IN THE AREA FROM NEAR 32N135W SW ACROSS THE FAR NW CORNER OF THE AREA THROUGH 28N140W TO ACROSS THE BIG ISLAND OF HAWAII AND BEYOND. THIS DEEP LAYERED TROUGH IS SUPPORTING A STRONG COLD FRONT NW OF THE AREA THAT WILL BE SWEEPING JUST NW OF THE AREA LATER TODAY...WITH A SECOND REINFORCING FRONT TO ATTEMPT TO ENTER NW PORTIONS SUN DISSIPATING IN THE NW WATERS MON. NW SWELL FROM A PREVIOUS FRONTAL SYSTEM MAINTAINS SEAS TO 11 FT IN THE NW WHICH WILL GRADUALLY DECAY AS IT CONTINUES TO PROPAGATE SE DURING THE NEXT 24 HOURS. ADDITIONAL PULSES OF EVEN LARGER NW SWELL WILL ARRIVE LATE SUN THROUGH EARLY NEXT WEEK WITH 15 FT SEAS EXPECTED NEAR 30N140W BY 48 HOURS. ELSEWHERE AT THE SURFACE...A 1023 MB HIGH PRES IS POSITIONED NEAR 28N129W WITH RIDGING EXTENDING SE FROM THE HIGH TO NEAR 20N110W. THE ASSOCIATED UPPER LEVEL RIDGING E OF 140W CONTINUES TO BLOCK FRONTAL SYSTEMS FROM ENTERING THE AREA FROM THE W-NW. AS THE NEXT ABOVE MENTIONED FRONTAL SYSTEM APPROACHES THE AREA THE HIGH IS BEING NUDGED SLIGHTLY E-SE...INCREASING THE PRES GRADIENT BETWEEN THE HIGH AND LOWER PRES E OF THE U.S. ROCKY MOUNTAINS AND THE SIERRA MADRE OCCIDENTALS. THIS HAS ALREADY RESULTED IN NW-N 20 KT WINDS WITHIN 180 NM OF THE W COAST OF BAJA CALIFORNIA TONIGHT AND THESE WINDS ARE EXPECTED TO PERSIST DURING THE NEXT 48 HOURS. THIS SLOWLY SHIFTING SURFACE HIGH HAS WEAKENED THE PRES GRADIENT N OF THE ITCZ...WHICH IS LIMITING FRESH TRADE WINDS IN A NARROW ZONE N OF THE ITCZ TO 12N W OF 135W. THIS NARROW AREA OF 20 KT TRADE WINDS IS EXPECTED TO BECOME REINVIGORATED AS THE HIGH STRENGTHENS TO 1027 MB WITH 20 KT WINDS REACHING TO 130W IN 24 HOURS AND THEN TO 120W IN 48 HOURS. GAP WINDS... GULF OF TEHUANTEPEC...20-30 KT NORTHERLY WINDS CONTINUE TO FLOW THROUGH THE GULF OF TEHUANTEPEC. WINDS WILL GRADUALLY DIMINISH TO LESS THAN 20 KT DURING THE NEXT 24 HOURS. NE SWELL UP TO 12 FT GENERATED BY EARLIER GALE FORCE CONDITIONS WILL DECAY TO 9 FT AS IT CONTINUES TO PROPAGATE TOWARD THE EQUATOR THROUGH 24 HOURS...SUBSIDING TO LESS THAN 8 FT BY 48 HOURS. GULF OF PAPAGAYO...A COLD FRONT HAS REACHED THE NE HONDURAS COAST IN THE NW CARIBBEAN SEA ALLOWING FOR NORTHEASTERLY GAP WIND FLOW IN THE GULF OF PAPAGAYO. A RECENT 0244Z ASCAT SCATTEROMETER PASS CAPTURED 20-25 KT WINDS AND SUSPECT RESULTANT SEAS TO HAVE BUILT TO 8 FT. THESE WINDS WILL PERSIST THROUGH 36 HOURS THEN WILL DIMINISH TO LESS THAN 20 KT BRIEFLY BEFORE RESURGING BY 48 HOURS. GULF OF PANAMA...LATEST MODEL GUIDANCE CONTINUES TO INDICATE 20 KT NORTHERLY WINDS IN THE GULF OF PANAMA AS THE PRES GRADIENT HAS TIGHTENED OVER WESTERN COLOMBIA. THESE WINDS ARE EXPECTED TO PERSIST THROUGH THE NEXT 48 HOURS. $$ LEWITSKY