000 AXPZ20 KNHC 192154 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC THU FEB 19 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. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...STRONG SURFACE HIGH PRES ACROSS THE WESTERN GULF OF MEXICO EXTENDS A SHARP RIDGE ALONG THE EASTERN SLOPES OF MEXICO TOWARD THE GULF OF TEHUANTEPEC AREA. THE PRES GRADIENT BETWEEN THE RIDGING AND LOWER PRES TO THE S ASSOCIATED WITH THE ITCZ 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 N OF THE ISTHMUS OF TEHUANTEPEC. WINDS WILL THEN CONTINUE TO DIMINISH TO 20 KT OR LESS IN ABOUT 36 HOURS. SEAS ARE UP TO 10-15 FT CURRENTLY AND WILL GRADUALLY SUBSIDE TO LESS THAN 8 FT IN THE IMMEDIATE GULF WATERS...WITH A LARGE AREA OF 8- 10 FT RESIDUAL NE SWELL PROPAGATING TO THE SW THROUGH 48 HOURS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 08N82W TO 04N90W. THE ITCZ CONTINUES FROM 04N90W TO 06N105W TO 04N120W TO 08N137W THEN RESUMES FROM 07N138W TO 06N140W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 75-90 NM SOUTH OF AXIS BETWEEN 85W AND 96W. NO SIGNIFICANT CONVECTION ELSEWHERE. ...DISCUSSION... A CUT-OFF MID TO UPPER LOW IS SPINNING NEAR 18N134W WITH A TROUGH EXTENDING SOUTH TO NEAR 08N134W. THIS CUT-OFF LOW REMAINS AT THE SOUTHERN END OF A NARROW UPPER TROUGH THAT EXTENDS ACROSS THE NW CORNER OF THE AREA FROM 30N132W TO 18N134W. A SURFACE TROUGH REFLECTION OF THIS UPPER-LEVEL FEATURE IS ANALYZED FROM 19N132W TO 13N134W. SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 150 NM NE OF A LINE FROM 16N128W TO 19N133W...AND FROM FROM 10N TO 16N BETWEEN 121W AND 125W IN ASSOCIATION WITH THESE SYSTEMS. A RECENT ASCAT PASS SHOWED AN AREA OF FRESH TO LOCALLY STRONG WINDS ON THE EAST SIDE OF THE TROUGH BUT IS MAINLY ASSOCIATED WITH THE CONVECTIVE ACTIVITY THERE. THE CUT-OFF IS FORECAST TO MOVE NE OVER THE NEXT 48 HOURS WHILE GRADUALLY WEAKENING. THE SURFACE TROUGH WILL REMAIN NEARLY STATIONARY AT LEAST THROUGH FRI. AN AREA OF SEAS TO 9 FT PERSISTS FROM 06N TO 12N BETWEEN 118W AND 127W. THIS IS DUE TO LONG PERIOD SWELL FROM THE NORTHWEST. THIS IS FORECAST TO DECAY TO 8 FT AS IT PROPAGATES SE AND SHRINK IN AREAL EXTENT...AFFECTING ONLY THE WATERS FROM 10N TO 13N BETWEEN 125W AND 128W BY 48 HOURS. 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. A 1028 MB SURFACE HIGH PRES LOCATED WELL N OF THE AREA EXTENDS A RIDGE TO THE SE TO NEAR 18N110W. 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. A SURFACE TROUGH IS WITHIN THE ITCZ AND EXTENDS FROM 10N137W TO 06N138W AND IS GENERATING A FEW SHOWERS. THE NEXT COLD FRONT IS EXPECTED TO REACH 30N140W BY SAT NIGHT. GAP WINDS... GULF OF PAPAGAYO...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. SEAS WILL BUILD TO 8-10 FT DOWNWIND OF THE GULF AND WILL PROPAGATE OFF TO THE SW-W THROUGH 48 HOURS. GULF OF PANAMA...FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED ACROSS THE GULF BY FRI 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. $$ GR