000 AXPZ20 KNHC 082103 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN FEB 08 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 1900 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...WINDS HAVE TURNED SOUTHEASTERLY IN THE SW GULF OF MEXICO AHEAD OF A DEEP LAYERED TROUGH CURRENTLY OVER THE U.S. SOUTHERN PLAINS...CUTTING OFF THE FRESH TO STRONG WINDS THAT HAD BEEN FUNNELING THROUGH CHIVELA PASS INTO THE GULF OF TEHUANTEPEC. BY LATE MON NIGHT...THE TROUGH SHOULD BRING A NEW ROUND OF NORTHERLY FLOW THROUGH THE WESTERN GULF AND CHIVELA PASS. WINDS WILL RAPIDLY INCREASE IN THE GULF OF TEHUANTEPEC AND ARE EXPECTED TO BECOME GALE FORCE BY SUNRISE TUE MORNING AND DIMINISH BELOW GALE FORCE AROUND SUNSET TUE EVENING. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 09N84W TO LOW PRES NEAR 05N90W 1012 MB TO 03N97W. THE ITCZ AXIS WAS ANALYZED FROM 03N97W TO 06N115W TO 03N131W TO 04N140W. SCATTERED MODERATE CONVECTION WAS OVER THE E PORTION N OF 03N W OF 82W TO A LINE FROM 03N97W TO 11N86W. A TROUGH FROM 14N123W TO 05N125W HAD SCATTERED MODERATE CONVECTION N OF THE ITCZ TO 10N W OF THE TROUGH TO 116W. ...DISCUSSION... A POTENT NORTHERN STREAM TROUGH IS RIDING A POWERFUL SOUTHWESTERLY UPPER JET THROUGH THE NORTH EASTERN PACIFIC WATERS PRIMARILY N OF THE AREA. THE COLD FRONT ASSOCIATED WITH THIS TROUGH LIES ACROSS FORECAST WATERS FROM 32N126W TO 24N136W TO 22N140W. W WINDS TO 25 KT LIE N OF 28N W OF THE FRONT. THE FRONT WILL CONTINUE TO WEAKEN TODAY AND IS EXPECTED TO DISSIPATE MON AS THE IMPETUS UPPER TROUGH RACES AWAY FROM THE AREA. A SWATH OF NW SWELL WITH SEAS OVER 8 FT IS ALREADY IN PLACE W OF A LINE FROM THE COAST OF BAJA CALIFORNIA NEAR 31N TO 05N136W TO 04N140W. SEAS AS HIGH AS 20 FT LIE IN THE AREA OF FRESH TO STRONG WINDS. THE LEADING EDGE OF THE AREA OF NW SWELL WITH SEAS OVER 8 FT WILL CONTINUE TO PROPAGATE SOUTHEASTWARD...SPREADING S ALONG THE COAST OF BAJA CALIFORNIA NORTE TO AROUND 26N THROUGH MON...AS MAXIMUM SEAS WILL SUBSIDE. A 1021 MB SURFACE HIGH NEAR 27N122W EXTENDS A RIDGE AXIS SOUTHEASTWARD TO 13N108W AND ANOTHER SOUTHWESTWARD TO BEYOND 18N140W. THIS HIGH IS EXPECTED TO WEAKEN AND MERGE WITH HIGH PRESSURE W OF THE AREA BEHIND THE COLD FRONT CURRENTLY OVER NW WATERS ON MON. THE MERGED HIGH WILL BE FORCED EASTWARD BY A VAST...DEEP LAYERED TROUGH OVER THE N CENTRAL PACIFIC. THIS WILL INCREASE THE PRESSURE GRADIENT BETWEEN THE EASTERN RIDGE AXIS AND TROUGHING OVER NW MEXICO. NW TO N WINDS ARE EXPECTED TO INCREASE TO A FRESH TO STRONG BREEZE ALONG THE COAST OF BAJA CALIFORNIA NORTE N OF 28N MON EVENING INTO TUE MORNING. TO THE W...TRADE WINDS WILL REMAIN A MODERATE TO FRESH BREEZE THROUGH THE END OF THE FORECAST PERIOD TUE AFTERNOON. THE 1830 UTC ASCAT PASS SHOWS A SOLID AREA OF 20 KT WINDS FROM 05N TO 10N W OF 138W...BUT THESE TRADE WINDS SHOULD WEAKEN SLIGHTLY AS THE DRIVING HIGH PRESSURE REORGANIZES. THE AFOREMENTIONED VAST...DEEP LAYERED TROUGH OVER THE N CENTRAL PACIFIC WILL GRADUALLY APPROACH THE NW WATERS ON TUE. SOUTHERLY WINDS WILL INCREASE TO A FRESH TO STRONG BREEZE W OF A LINE FROM 30N136W TO 26N140W TUE AND SEAS BUILD TO 8-12 FT HERE BY TUE AFTERNOON. SHOWERS AND THUNDERSTORMS WILL LIKELY BE JUST W OF THIS AREA BY TUE AFTERNOON. AN UPPER LEVEL LOW LIES NEAR 07N125W AND REFLECTS A SURFACE TROUGH FROM 14N123W TO 05N125W. A BROAD UPPER JET LIES ON THE E SIDE OF THE UPPER LOW. ASCENT ASSOCIATED WITH THE LEFT FRONT QUADRANT OF THIS JET IS LIFTING TROPICAL MOISTURE AND ENHANCING CONVECTION N OF THE ITCZ TO 10N W OF THE TROUGH TO 116W. THE UPPER LOW IS FORECAST TO SHIFT NORTHEASTWARD AND PHASE WITH THE DEEP LAYERED TROUGH THAT IS SUPPORTING THE COLD FRONT CURRENTLY OVER NW WATERS. THE ASSOCIATED SURFACE TROUGH WILL GRADUALLY DISSIPATE THROUGH MON. GAP WINDS.... GULF OF PAPAGAYO...WINDS IN THE GULF OF PAPAGAYO HAVE DIMINISHED BELOW THE ADVISORY CRITERIA OF 20-25 KT IN RESPONSE TO THE WEAKENING PRESSURE GRADIENT ACROSS CENTRAL AMERICA. $$ SCHAUER