000 AXPZ20 KNHC 232152 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED DEC 23 2015 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A SURFACE TROUGH EXTENDS FROM 06N77W TO 05N90W TO 06N102W. THE ITCZ AXIS CONTINUES FROM 06N102W TO 07N124W TO BEYOND 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 07N TO 10N BETWEEN 115W AND 122W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF AXIS BETWEEN 126W AND 131W...AND WITHIN 75 NM N OF AXIS W OF 138W. ...DISCUSSION... A 1031 MB HIGH PRES LOCATED NEAR 34N143W EXTENDS A RIDGE SE ACROSS THE FORECAST WATERS TO NEAR 21N112W. THE PRESSURE GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN THE VICINITY OF THE ITCZ IS CURRENTLY SUPPORTING A LARGE AREA OF TRADE WINDS... PARTICULARLY FROM 07N TO 22N W OF 125W...AND FROM 08N TO 16N BETWEEN 115W AND 125W. IN ADDITION...THE PRES GRADIENT BETWEEN THE SAME RIDGE AND A TROUGH ALONG THE GULF OF CALIFORNIA IS ALSO PRODUCING AN AREA OF FRESH TO STRONG NW JUST OFF OF THE BAJA CALIFORNIA NORTE...MAINLY N OF 28N E OF 125W AS NOTED IN AN EARLIER ASCAT SATELLITE PASS. CONCURRENT ALTIMETER PASSES ALSO INDICATED SEAS TO 9 TO 13 FT...LIKELY DUE IN PART TO ONGOING NW SWELL. THE HIGH PRES WILL REMAIN NEARLY STATIONARY OVER THE NEXT 24 HOURS WITH FRESH TO STRONG PERSISTING JUST OFF OF BAJA CALIFORNIA NORTE AND ACROSS THE TROPICS N OF THE ITCZ. THE SWELL IS THE MAIN COMPONENT OF AN AREA OF SEAS 8 FT OR GREATER MAINLY WEST OF 110W INCLUDING THE REVILLAGIGEDO ISLANDS. LOOKING AHEAD...THE PRES GRADIENT WILL TIGHTEN AGAIN FRI EVENING INTO SAT WITH 20-25 KT CONDITIONS DEVELOPING AGAIN N OF 24N... WITH ANOTHER ROUND OF 10-15 FT COMBINED SEAS. THE GRADIENT WILL ALSO TIGHTEN ACROSS THE NORTHERN GULF OF CALIFORNIA SUPPORTING NW 20-25 KT WINDS TO THE N OF 30N ON FRI NIGHT...AND 20-30 KT WINDS ACROSS THE ENTIRE GULF LATE SAT...WITH A MINIMAL GALE POSSIBLE ACROSS THE NORTHERN GULF BY SAT. NORTHERLY 20-25 KT WINDS EXPECTED ACROSS THE GULF OF TEHUANTEPEC ON MON AFTERNOON INCREASING TO 20-30 KT CONDITIONS ON MON NIGHT. GAP WINDS FLOW HAS TAPERED OFF FOR NOW THROUGH THE GULF OF PAPAGAYO AND FARTHER DOWNSTREAM...BUT GUIDANCE SUGGESTS ANOTHER PULSE OF STRONG WINDS THU NIGHT INTO FRI. THE RESULTANT NE SWELL WILL PROPAGATE SW RESULTING IN 7-10 FT COMBINED SEAS AS FAR DOWNSTREAM AS 10N93W DURING THE AFTERNOONS. THE SOURCE REGION OF THESE WINDS WILL ALSO EXPAND NORTHWARD FROM THE GULF OF PAPAGAYO ALONG THE COAST OF NICARAGUA TO THE GULF OF FONSECA BY FRI NIGHT INTO SAT MORNING. FRESH NORTHERLY FLOW IS LIKELY INTO THE GULF OF PANAMA AS WELL. THE NEXT COLD FRONT IS FORECAST TO REACH NEAR 30N140W ON SAT NIGHT ACCOMPANIED BY ONLY GENTLE TO MODERATE NORTHERLY WINDS... BUT FOLLOWED BY ANOTHER BATCH OF LONG PERIOD NW SWELL RESULTING IN BUILDING SEAS UP TO 13-14 FT ACROSS THE FAR NW PORTION BUT GENERALLY SUBSIDING TO 10-12 FT BY EARLY NEXT WEEK AS THE FRONT WASHES OUT ACROSS THE NW PART OF THE DISCUSSION AREA. $$ GR