000 AXPZ20 KNHC 200333 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI FEB 20 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 TEHUANTEPEC GALE WARNING...PERSISTENT STRONG HIGH PRESSURE EXTENDING SOUTHWARD ACROSS THE MEXICAN COASTAL PLAINS TOWARD THE GULF OF TEHUANTEPEC AREA CONTINUES TO MAINTAIN A TIGHT PRESSURE GRADIENT ACROSS THE ISTHMUS OF TEHUANTEPEC. THIS IS SUPPORTING 30-40 KT NORTHERLY WINDS WHICH WILL PERSIST UNTIL EARLY FRI MORNING WHEN THE PRES GRADIENT WILL WEAKEN AND WINDS WILL TURN SOUTHERLY IN THE GULF OF MEXICO. WINDS WILL THEN CONTINUE TO DIMINISH TO 20 KT OR LESS IN ABOUT 24 HOURS. SEAS ARE UP TO 10-15 FT CURRENTLY AND WILL GRADUALLY SUBSIDE TO LESS THAN 8 FT IN THE IMMEDIATE GULF WATERS...BUT A LARGE AREA OF 8- 10 FT RESIDUAL NE SWELL PROPAGATING TO THE SW WILL PERSIST THROUGH 48 HOURS COVERING ROUGHLY THE WATERS FROM 03N TO 11N BETWEEN 90W AND 108W BY LATE FRI...AND FROM 04N TO 10N BETWEEN 90W AND 110W BY LATE SAT. GULF OF PAPAGAYO GALE WARNING...A TIGHT PRES GRADIENT BETWEEN LOWER PRES ASSOCIATED WITH THE ITCZ SW OF THE AREA AND HIGH PRES RIDGING ALONG THE SPINE OF CENTRAL AMERICA CONTINUES TO SUPPORT FRESH TO STRONG NE WINDS IN THE GULF OF PAPAGAYO. THESE WINDS ARE FORECAST TO INCREASE TO 30 KT BY SUNRISE FRI AS THE GRADIENT TIGHTENS AND WITH THE AID OF NOCTURNAL DRAINAGE FLOW. WINDS ARE FORECAST TO FURTHER INCREASE TO MINIMAL GALE FORCE BY SAT AT 0600 UTC. AS A RESULT...A GALE WARNING HAS BEEN ISSUED WITH THIS FORECAST PACKAGE. 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... MONSOON TROUGH FROM 08N85W TO 03N102W. ITCZ FROM 03N102W TO 05N120W TO 06N139W. NO SIGNIFICANT CONVECTION. ...DISCUSSION... A CUT-OFF MID TO UPPER LOW PERSISTS NEAR 18N133W WITH A TROUGH EXTENDING SOUTH TO NEAR 08N133W. THIS CUT-OFF LOW REMAINS AT THE SOUTHERN END OF A NARROW UPPER TROUGH THAT EXTENDS ACROSS THE NW CORNER OF THE AREA FROM 30N131W TO 18N133W. A SURFACE TROUGH REFLECTION OF THIS UPPER-LEVEL FEATURE IS ANALYZED FROM 20N132W TO 15N133W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE ASSOCIATED WITH THESE SYSTEMS...PARTICULARLY FROM 13N TO 17N BETWEEN 122W AND 124W. SCATTEROMETER DATA SHOWED AN AREA OF FRESH TO LOCALLY STRONG WINDS ON THE EAST SIDE OF THE TROUGH BUT APPEARS TO BE ASSOCIATED WITH THE CONVECTIVE ACTIVITY THERE. THE CUT-OFF LOW IS FORECAST TO MOVE NE OVER THE NEXT 36-48 HOURS WHILE GRADUALLY WEAKENING. THE SURFACE TROUGH WILL REMAIN NEARLY STATIONARY THROUGH FRI. BASED ON AN ALTIMETER PASS AND MARINE GUIDANCE AN AREA OF SEAS TO 8 FT IS NOTED FROM 05N TO 11N BETWEEN 118W AND 125W. THIS IS DUE TO LONG PERIOD SWELL FROM THE NORTHWEST. THIS IS FORECAST TO DECAY TO LESS THAN 8 FT BY LATE FRI. ADDITIONAL PULSES OF LONG PERIOD NW SWELL SHOULD REACH THE FAR NW CORNER OF THE FORECAST AREA BY SAT...WITH BUILDING SEAS TO 10 FT NEAR 30N140W BY SAT NIGHT. THIS SWELL EVENT WILL LIKELY BE ASSOCIATED WITH THE NEXT COLD FRONT FORECAST TO REACH THE FAR NW CORNER OF THE AREA BY SAT NIGHT. A 1027 MB SURFACE HIGH PRES LOCATED WELL N OF THE AREA EXTENDS A RIDGE TO THE SE TO NEAR 20N112W. THIS SYSTEM WILL REMAIN NEARLY STATIONARY DURING THE NEXT 24 HOURS PRODUCING A SLIGHT INCREASE IN THE TRADE WIND FLOW FROM 10N TO 20N BETWEEN 120W AN 130W OVER THE NEXT COUPLE OF DAYS. CURRENTLY...PRES GRADIENT BETWEEN THE RIDGE AND THE AFOREMENTIONED SURFACE TROUGH IS NOW PRODUCING AN AREA OF FRESH NE WINDS FROM 20N TO 25N BETWEEN 125W AND 135W. SCATTEROMETER DATA CONFIRMED THE PRESENCE OF THESE WINDS. GAP WINDS... GULF OF PANAMA...FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED ACROSS THE GULF BY EARLY FRI MORNING...AND AGAIN BY EARLY SAT MORNING AS WINDS FUNNEL INTO THE GULF OF PANAMA FROM THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA. GULF OF CALIFORNIA...ELONGATED SURFACE TROUGHING WILL REMAIN ACROSS THE GULF THROUGH 48 HOURS WITH MAINLY LIGHT AND VARIABLE WINDS DEPENDENT ON THE EXACT LOCATION OF THE TROUGH AXIS... OCCASIONALLY INCREASING TO MODERATE LEVELS. SEAS WILL BE 2 FT OR LESS THROUGH 48 HOURS...EXCEPT NEAR THE MOUTH OF THE GULF WHERE SEAS WILL BE 3-4 FT. MARINE GUIDANCE SUGGESTS INCREASING WINDS ACROSS THE N PART OF THE GULF SAT NIGHT INTO SUN AS A LOW PRES DEVELOPS THERE. $$ GR