000 AXPZ20 KNHC 160946 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT FEB 16 2013 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0930 UTC. ...SPECIAL FEATURE... THE MAIN FORECAST ISSUE OVER THE NEXT 24 TO 48 HOURS WILL THE DEVELOPMENT OF STORM FORCE WINDS THROUGH THE GULF OF TEHUANTEPEC. COOLER AND DRIER AIR IS PUSHING THROUGH THE WESTERN GULF OF MEXICO AND THE CHIVELA PASS IN THE ISTHMUS OF TEHUANTEPEC TOWARD THE GULF OF TEHUANTEPEC THIS MORNING. A 04 UTC ASCAT PASS INDICATED WINDS OF 15 TO 20 KT IN THE GULF OF TEHUANTEPEC SO FAR...AND THIS IS EXPECTED TO REACH GALE FORCE BY MID MORNING. A REINFORCING SURGE OF COOLER AIR BACKED BY STRONG HIGH PRES WILL PUSH INTO THE GULF OF TEHUANTEPEC BY THIS EVENING...ALLOWING WINDS TO INCREASE TO STORM FORCE THROUGH EARLY SUN MORNING. WINDS WILL START TO DIMINISH TO BELOW GALE FORCE LATER ON SUN AS THE DOME OF COOL AIR OVER THE GULF OF MEXICO MODIFIES AND SHIFTS EAST. WINDS TO 30 KT ARE STILL POSSIBLE MON NIGHT INTO EARLY TUE WITH DRAINAGE AFFECTS AND LINGER INFLUENCES OF THE COOLER AIR FILTERING INTO THE AREA. WW3 ENSEMBLE GUIDANCE INDICATES SEAS WILL REACH AS HIGH AS 23 FT WHICH IS PLAUSIBLE GIVEN STORM FORCE CONDITIONS OVER A PERIOD OF 12 HOURS AND A FETCH OF UP TO 240 NM. A BROAD DOWNSTREAM PLUME OF WINDS AT LEAST 20 TO 25 KT AND SEAS 8 FT OR GREATER WILL ARC AS FAR OUT AS 600 NM FROM THE GULF. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS IS NOT DISCERNIBLE ON THE 0000 UTC MAP. THE ITCZ EXTENDS FROM 08N98W TO 06N108W TO 08N122W TO 03N136W TO 03N140W. NO SIGNIFICANT CONVECTION. ...DISCUSSION... A DEEP LAYER RIDGE WILL REMAIN ANCHORED N OF THE HAWAIIAN ISLANDS THROUGH MID WEEK...WEST OF AN ELONGATED MID/UPPER TROUGH EXTENDING FROM THE COAST OF NORTHERN CALIFORNIA TO A WEAK UPPER LOW CENTERED NE OF THE BIG ISLAND NEAR 21N152W. FARTHER SOUTH...A NEGATIVELY TILTED UPPER TROUGH EXTENDING FROM 18N128W TO 06N120W IS PROVIDING SUPPORT TO A SURFACE TROUGH BREAKING THE ITCZ NEAR 123W FROM 06N TO 11N. THE UPPER TROUGH IS ALSO ENHANCING CONVECTION IN THE CONVERGENT AREA AHEAD OF THE TROUGH NEAR 08N125W. GLOBAL MODELS SUGGEST THE SURFACE TROUGH WILL START TO DAMPEN OUT SUN AND MON AS IT TRANSITS W OF THE UPPER TROUGH WHICH WILL BE WEAKENING AND SHIFTING E. A 1036 MB HIGH PRES AREA ASSOCIATED WITH THE DEEP LAYER RIDGE WILL REMAIN N OF THE AREA NEAR 40N140W. THE PRES GRADIENT S OF THE HIGH PRES AND AGAINST THE SURFACE TROUGH ALONG THE ITCZ IS SUPPORTING A BROAD AREA OF FRESH TO STRONG TRADE WINDS AS NOTED IN VARIOUS SCATTEROMETER AND ALTIMETER PASSES OVER THE PREVIOUS 12 TO 18 HOURS IN THE GENERAL AREA FROM 12N TO 20N W OF 125W. ALTIMETER DATA ALSO SHOW SEAS OF 8 TO 10 FT IN THIS AREA OF TRADE WINDS. THE 00Z WW3 INITIALIZATION INDICATES SEAS TO 12 FT FROM 04N TO 15N W OF 130W JUST TO THE WEST OF AN ALTIMETER PASS...AND IS PLAUSIBLE GIVEN GREATER FETCH OF NE TRADES. WW3 AND ECWAVE GUIDANCE SUGGEST TRAINS OF NW SWELL PUSHING INTO THE WATERS S OF 32N OVER THE NEXT SEVERAL DAYS MIXING WITH THE FRESH NE SWELL IN THE TRADE WIND BELT. GULF OF CALIFORNIA...STRONG HIGH PRES BUILDING OVER THE GREAT BASIN WELL TO THE NORTH IS RESULTING IN STRONG NW WINDS DOWN THE MOST OF THE LENGTH OF THE GULF OF CALIFORNIA THIS MORNING. THESE WINDS WILL DIMINISH LATER TODAY AS THE HIGH PRES WEAKENS. GULF OF PAPAGAYO...THE STRONG HIGH PRES BUILDING OVER THE GULF OF MEXICO INTO SOUTHERN MEXICO AND CENTRAL AMERICA THAT IS PROMPTING STORM FORCE WINDS IN THE GULF OF TEHUANTEPEC WILL ALSO INDUCE A SURGE OF TRADE WINDS INTO THE GULF OF PAPAGAYO LATE SAT INTO EARLY SUN...PERSISTING THROUGH EARLY TUE WITH STRONGEST WINDS DURING THE OVERNIGHT AND EARLY MORNING HOURS. $$ CHRISTENSEN