000 AXPZ20 KNHC 210333 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT FEB 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...SPECIAL FEATURES... GULF OF PAPAGAYO GALE WARNING...A SHORT DURATION GALE FORCE WIND EVENT IS EXPECTED ACROSS THIS GULF OVERNIGHT TONIGHT INTO EARLY SAT MORNING. THIS WILL BE ASSOCIATED WITH A TIGHT PRES GRADIENT ACROSS THE NW CARIBBEAN AND CENTRAL AMERICA AND THE ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW. WINDS ARE FORECAST TO DIMINISH TO 25-30 KT BY EARLY SAT AFTERNOON. WINDS WILL FURTHER DIMINISH AND REMAIN 20-25 KT SAT EVENING THROUGH LATE MON. SEAS WILL BUILD TO 8-10 FT WITH THE STRONGEST WINDS DOWNWIND OF THE GULF AND WILL PROPAGATE OFF TO THE SW-W THROUGH 48 HOURS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... VERY WEAK MONSOON TROUGH IS ANALYZED FROM 09N84 TO 04N94W. THE ITCZ EXTENDS FROM 04N94W TO 05N104W TO 03N114W TO 06N125W TO 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 75 NM N OF ITCZ AXIS BETWEEN 122W AND 125W...AND WITHIN 45 NM S OF ITCZ AXIS BETWEEN 127W AND 129W. ...DISCUSSION... THE CUT-OFF MID TO UPPER LOW THAT HAS BEEN GENERATING SHOWERS AND TSTMS OVER THE WESTERN PART OF THE AREA DURING THE PREVIOUS DAYS IS FINALLY LIFTING NE WHILE WEAKENING. THE LOW IS NOW CENTERED NEAR 23N128W WITH A TROUGH EXTENDING SW TO NEAR 07N138W. THIS CUT-OFF LOW REMAINS AT THE SOUTHERN END OF A LARGE NARROW UPPER TROUGH THAT EXTENDS FROM CENTRAL CALIFORNIA SW TO 30N128W AND S TO THE AFOREMENTIONED LOW. TO THE SW OF THE CUT- OFF LOW...SATELLITE IMAGERY REVEALS THE PRESENCE A SWIRL OF LOW CLOUDS NEAR 19N133W. A SURFACE TROUGH IS ANALYZED IN THIS AREA AND EXTENDS FROM 11N132W TO 17N133W. CLUSTERS OF MODERATE TO STRONG CONVECTION HAVE DEVELOPED THIS EVENING FROM 08.5N TO 12N BETWEEN 119W AND 122W...AND FROM 08.5N TO 11N BETWEEN 122W AND 125.5W. A DIFFLUENT PATTERN ALOFT AHEAD OF THE AFOREMENTIONED UPPER-LEVEL TROUGH IS HELPING TO INDUCE THIS CONVECTIVE ACTIVITY. THE CUT-OFF LOW IS FORECAST TO MOVE NE OVER THE NEXT 48 HOURS WHILE GRADUALLY WEAKENING. THE SURFACE TROUGH WILL DRIFT WESTWARD OVER THE NEXT 48 HOURS. BY MON...MARINE GUIDANCE SUGGESTS THE PRESENCE OF A BETTER DEFINED SURFACE TROUGH EXTENDING ACROSS THE WEST-CENTRAL WATERS. PRES GRADIENT BETWEEN THIS TROUGH AND A 1030 MB HIGH PRES LOCATED NW OF THE AREA COULD BRING SOME INCREASE IN WINDS AND SEAS. THE NEXT COLD FRONT IS FORECAST TO APPROACH THE NW PORTION OF THE REGION LATE SAT REACHING NEAR 30N140W BY SAT NIGHT. WAVEWATCH GUIDANCE INDICATES THAT SEAS TO 9 FT IN NW SWELLS WILL OCCUR W OF A LINE FROM 30N138W TO 23N140W BY SAT AFTERNOON. THE FRONT WILL WEAKEN AS IT MOVES ACROSS THE NW WATERS BY EARLY SUN EVENING. A NEW SET OF LONG PERIOD NW SWELL WILL FOLLOW THE FRONT BUILDING SEAS UP TO 10 FT W OF A LINE FROM 30N128W TO 20N134W TO 14N138W BY SUN EVENING. ALSO AT THE SURFACE...A 1028 HIGH CENTER LOCATED WELL N OF THE AREA EXTENDS A RIDGE SE ACROSS THE FORECAST WATERS TO NEAR 20N112W. THE HIGH IS FORECAST TO REMAIN NEARLY STATIONARY DURING THE NEXT 24 HOURS. GAP WINDS... GULF OF TEHUANTEPEC...A RECENT RAPIDSCAT PROVIDED OBSERVATIONS OF NORTHERLY WINDS IN THE 15-20 KT RANGE ACROSS THIS GULF. THE PRES GRADIENT HAS DIMINISHED ACROSS THE ISTHMUS THE TEHUANTEPEC AND WINDS HAVE VEERED TO THE SE AND S ACROSS THE WESTERN GULF OF MEXICO. NE TO E SWELL GENERATED BY THE GALE FORCE WINDS ACROSS THE GULF OF TEHUANTEPEC DURING THE PREVIOUS DAYS COMBINED WITH SEAS PROPAGATING DOWNWIND OF THE GULF OF PAPAGAYO IS PRODUCING A LARGE AREA OF SEAS IN THE 8-10 FT RANGE FROM 04N TO 12N BETWEEN 90W AND 105W. THIS IS FORECAST TO DECAY TO LESS THAN 8 FT BY SUN MORNING. THE NEXT GULF OF TEHUANTEPEC GAP WIND EVENT IS EXPECTED ON MON WITH WINDS LIKELY INCREASING TO 25-30 KT. GULF OF PANAMA...FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED ACROSS THIS GULF BY LATE TONIGHT AND EARLY SAT MORNING BEFORE DIMINISHING TO 20 KT OR LESS LATER DURING THE AFTERNOON. THESE WINDS WILL MATERIALIZE AGAIN LATE SAT NIGHT INTO EARLY SUN MORNING AS HIGH OVER THE NW CARIBBEAN TIGHTENS THE PRES GRADIENT OVER THE SW CARIBBEAN SEA. GULF OF CALIFORNIA...MODEL OUTPUT SUGGESTS THAT SW WINDS WILL INCREASE TO 20-25 KT OVER THE FAR NORTHERN SECTOR LATE SAT NIGHT INTO SUN AS LOW PRES FORMS OVER THAT PART OF THE GULF. $$ GR