000 AXPZ20 KNHC 122215 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT FEB 12 2011 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 2115 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 01N79W TO 02N88W TO 02N97W TO 07N123W TO 08N135W TO 06N140W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 180 NM N OF AXIS BETWEEN 117W AND 124W. ...DISCUSSION... AN UPPER LEVEL BLOCKING PATTERN CONTINUES ACROSS THE EPAC BETWEEN 100W AND 150W...WITH A CUT OFF UPPER CYCLONE CENTERED NEAR 18N135W...AND A NEGATIVE TILT TROUGH TO ITS SE EXTENDING FROM 14N122W TO NEAR 05N109W. THE UPPER CYCLONE WAS INDUCING A WEAKNESS IN THE LOW LEVEL FLOW TO ITS SOUTH...PRODUCING A BROAD AND WEAK INVERTED TROUGH...WHILE BROAD UPPER DIVERGENCE E OF THE UPPER TROUGH WAS VENTING ISOLATED MODERATE TO STRONG CONVECTION OFF THE ITCZ BETWEEN 14N AND 22N. THE TROUGH EMBEDDED IN THE ITCZ ALONG ABOUT 127W CONTINUES TO WEAKEN AND BECOME LESS ORGANIZED AS IT MOVES SLOWLY W ENCOUNTERING STRONG WIND SHEAR TO 30 KT. IT WILL CONTINUE TO WEAKEN INTO A LOW AMPLITUDE WAVE FEATURE OVER THE NEXT 24 HOURS AND SLOWLY DISSIPATE. A COLD FRONT WHICH EXTENDS FROM 40N135W TO 23N150W WILL MOVE E-NE INTO THE NW PORTION OF THE AREA IN ABOUT 12 HOURS...WITH S WINDS TO 25-30 KT IMMEDIATELY AHEAD OF THE FRONT AND NW WINDS TO 20-25 KT BEHIND THE FRONT. SEAS ASSOCIATED WITH THE FRONT WILL BUILD TO AROUND 13-14 FT IN NW SWELL IN EXTREME NW PART OF THE FORECAST AREA DURING THE NEXT 30-60 HOURS. THE GFS MODEL SHOWS THE FRONT LIFTING N OF 30N NEAR 130W IN ABOUT 48 HOURS. A HIGH PRES RIDGE EXTENDS SW FROM A 1024 MB HIGH OFF THE CENTRAL CALIFORNIA COAST TO 20N150W. THE RIDGE WILL ACT TO BUFFER THE APPROACH OF THE COLD FRONT INTO THE FORECAST AREA. EXPECT RIDGE TO REMAIN FIRMLY IN PLACE FROM SOUTHERN CALIFORNIA THROUGH A HIGH CENTERED NEAR 25N125W TO AROUND 22N137W THROUGH MON NIGHT ALLOWING THE COLD FRONT TO RIDE UP AND OVER THE RIDGE. GAP WINDS... GULF OF TEHUANTEPEC...COLD AIR CONTINUES TO SURGE ACROSS THE ISTHMUS OF TEHUANTEPEC. AFTERNOON OBSERVATIONS AT LAND STATION IXTEPEC MEXICO HAVE REPORTED 40 KT WITH GUSTS TO 50 KT ALL AFTERNOON...WHILE PARTIAL SCATTEROMETER PASSES FROM THIS MORNING THROUGH NOON ONLY SHOWED MINIMAL GALE FORCE WINDS. HIGH PRES OVER SE TEXAS WILL INTENSIFY THROUGH THIS EVENING...SENDING A REINFORCING SURGE OF COLD AIR THROUGH THE PASS WHICH WILL INCREASE WINDS TO STORM FORCE LATE THIS EVENING AND EARLY TONIGHT AS THE PRES GRADIENT OVER SE MEXICO TIGHTENS. A SLIGHT LESSENING OF THE GRADIENT ON SUN AFTERNOON SHOULD ALLOW FOR THE WINDS TO DIMINISH BELOW 50 KT AND RETURN TO GALE FORCE. SEAS WILL BUILD TO UP TO 19 FT COINCIDENT WITH THE STORM FORCE CONDITIONS. NE SWELL GENERATED BY THESE WINDS WILL SPREAD SW TO 04N BY SUN NIGHT. GULF OF PAPAGAYO...WINDS ARE EXPECTED TO INCREASE TO 20 TO 25 KT TONIGHT AS COOL DRAINAGE FLOW RESUMES OFF OF CENTRAL AMERICA BY THE EARLY MORNING HOURS. THESE FRESH WINDS WILL PERSIST THROUGH AT LEAST SUN NIGHT AS TRADES INCREASE IN THE WESTERN CARIBBEAN SEA. GULF OF PANAMA...NE TRADE WINDS TO 20 KT ARE FILTERING ACROSS THE ISTHMUS OF PANAMA AND BECOMING NLY ACROSS THE GULF OF PANAMA N OF 06N BETWEEN 78W AND 80W. WINDS WILL DIMINISH BELOW 20 KT IN ABOUT 24 HOURS AS THE TRADES N OF THE ISTHMUS WEAKEN. GULF OF CALIFORNIA...PRES GRADIENT BETWEEN HIGH PRES OVER THE U.S. INTER-MOUNTAIN WEST AND BROAD SURFACE TROUGH OVER NW MEXICO IS GENERATING 20 KT NW WINDS FUNNELING THROUGH THE S HALF OF THE GULF OF CALIFORNIA THIS AFTERNOON. WINDS WILL REMAIN AROUND 20 KT OVERNIGHT THEN DIMINISH BELOW 20 KT IN ABOUT 24 HOURS AS THE GRADIENT RELAXES. $$ STRIPLING