000 AXPZ20 KNHC 160932 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT APR 16 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 WAS ANALYZED FROM 04N77W TO LOW PRES NEAR 06N92W TO 03N105W TO 04N115W TO 02N130W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 180 NM N OF THE AXIS E OF 79W. SIMILAR CONVECTION WAS WITHIN 120 NM IN THE N AND 240 NM IN THE S SEMICIRCLES OF THE LOW. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WAS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 96W AND 99W. ...DISCUSSION... AN UPPER LEVEL RIDGE/TROUGH/RIDGE PATTERN REMAINS OVER THE N WATERS. THE WESTERN UPPER RIDGE REACHES FROM 32N130W TO 10N140W. AN UPPER TROUGH IS W OF THIS RIDGE AND THE DISCUSSION AREA JUST E OF THE BIG ISLAND OF HAWAII. THIS TROUGH IS TRANSPORTING MID TO UPPER LEVEL MOISTURE ACROSS THE FAR NW PORTION OF THE AREA. ANOTHER UPPER TROUGH IS E OF THE RIDGE OVER THE N CENTRAL PORTION EXTENDING FROM S CALIFORNIA SW TO NEAR 15N124W. A 40-55 KT JET WITH SWLY FLOW AHEAD OF IT IS TRANSPORTING ABUNDANT MID TO UPPER LEVEL MOISTURE FROM THE SOUTHERN TIP OF BAJA CALIFORNIA INTO AND ACROSS CENTRAL MEXICO. MODERATE TO STRONG SUBSIDENCE COVERS THE REMAINDER OF THE AREA N OF 20N E OF 135W. UPPER LEVEL RIDGING DOMINATES THE REST OF THE REGION E OF 100W...INCLUDING SE MEXICO AND CENTRAL AMERICA. UPPER DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ E OF 100W. IN THE DEEP TROPICS...AN ANTICYCLONIC CIRCULATION IS LOCATED NEAR 08N120W. A DIFFLUENT PATTERN ALOFT ON THE EAST SIDE OF THIS ANTICYCLONE IS PROMOTING THE DEVELOPMENT OF CONVECTION ALONG THE ITCZ AND NEAR A SURFACE TROUGH THAT EXTENDS FROM 11N118W TO 07N116W. SCATTERED MODERATE TO STRONG CONVECTION WAS N OF 08N WITHIN 180 NM EITHER SIDE OF THE TROUGH. AN 1008 MB AREA OF LOW PRES IS EMBEDDED IN THE ITCZ POSITIONED NEAR 06N92W AS INDICATED BY A RECENT 0358 UTC ASCAT PASS. THIS ASCAT PASS SHOWED ONLY 10-15 KT WINDS AND BARELY A CLOSED SURFACE CIRCULATION. RECENT IR SATELLITE IMAGERY SHOWS CLOUD TOPS WARMING BY 10-20 DEGREES C DURING THE PAST 6 HOURS. THE 00 UTC OPERATIONAL GFS SOLUTION PROGS A 20-25 KT LOW REMAINING NEARLY STATIONARY FOR THE NEXT FEW DAYS AND THEN TAKING OFF TO THE W AROUND 15 KT BY THE MIDDLE PART OF NEXT WEEK. MEANWHILE THE NEW 00 UTC ECMWF HI-RES SOLUTION IS MUCH MORE CONSERVATIVE FORECASTING ONLY 5-10 KT WINDS AROUND THE LOW WITH DISSIPATION OCCURRING WITHIN THE NEXT 48 HOURS. PREFER TO FOLLOW THE MORE CONSERVATIVE ECMWF SOLUTION AT THIS TIME. ELSEWHERE AT THE SURFACE...A 1027 MB HIGH IS CENTERED NEAR 32N133W WITH A RIDGE AXIS EXTENDING SE TO AROUND 17N115W. THE COMBINATION OF THIS RIDGING AND A SURFACE TROUGH LOCATED OVER NW MEXICO IS RESULTING IN FRESH NW WINDS ACROSS THE GULF OF CALIFORNIA N OF 25N AS CAPTURED BY 0406 UTC EXPERIMENTAL ENHANCED ASCAT COASTAL WINDS...ALONG WITH 20 KT NW WINDS W OF THE BAJA CALIFORNIA PENINSULA WHERE THE GRADIENT IS ALSO TIGHT. MODEL GUIDANCE INDICATES THE PRES GRADIENT WILL RELAX ALLOWING FOR WINDS TO DIMINISH TO LESS THAN 20 KT IN THE GULF THIS AFTERNOON. THEREAFTER...SURFACE LOW PRES WILL DEEPEN OVER S NEVADA AND SE CALIFORNIA WITH 20 KT SOUTHERLY WINDS COMMENCING BY IN THE N GULF SUN AFTERNOON THEN WEAKENING BY MON MORNING AS THE INTERIOR LOW DISSIPATES. MODERATE TO FRESH TRADE WINDS S OF THE HIGH CONTINUE FROM 08N TO 18N W OF 126W ALTHOUGH THEY ARE EXPECTED TO DIMINISH TO LESS THAN 20 KT BY EARLY SUN MORNING AS THE HIGH SHIFTS SW AND WEAKENS TO 1023 MB. MEANWHILE SEAS ARE 8-11 FT IN MIXED NE WIND WAVES AND NW SWELL OVER THE MAJORITY OF THE NW WATERS. LONG PERIOD SW SWELLS WILL OVERTAKE THE DECAYING NORTHERLY SWELL DURING THE NEXT FEW DAYS. EXTENDED MODEL GUIDANCE FORECASTS A NEW AND MORE POWERFUL SET OF SW SWELL WITH PERIODS OF 18-20 SECONDS REACHING THE PACIFIC COASTLINES INCLUDING SOUTHERN CALIFORNIA BY THE END OF THE UPCOMING WEEK. ALSO...A BRIEF 20 KT NORTHERLY WIND EVENT IS EXPECTED IN THE GULF OF TEHUANTEPEC SAT NIGHT INTO SUN AFTERNOON AS A COLD FRONT MOVES THROUGH THE SW GULF OF MEXICO. $$ LEWITSKY