000 AXPZ20 KNHC 250349 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED NOV 25 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 0230 UTC. ...SPECIAL FEATURES... NEWLY UPGRADED HURRICANE SANDRA WAS CENTERED NEAR 12.0N 107.9W AT 0300 UTC MOVING WNW OR 290 DEGREES AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 991 MB. MAXIMUM SUSTAINED WINDS HAVE RECENTLY INCREASED TO 65 KT WITH GUSTS TO 85 KT. NUMEROUS STRONG CONVECTION WAS OCCURRING WITHIN 90 NM NW AND 45 NM ACROSS THE SE SEMICIRCLES...WHILE SCATTERED MODERATE TO STRONG CONVECTION WAS IN BANDS ELSEWHERE WITHIN 360 NM NE AND 180 NM SW SEMICIRCLES. SANDRA HAS CONTINUED TO IMPROVE INORGANIZATION TONIGHT...AS IT REMAINS UNDERNEATH A LARGE UPPER LEVEL HIGH PRESSURE SYSTEM. SANDRA IS EXPECTED TO TURN NW OVERNIGHT AND THEN N ON WEDNESDAY...AND IS EXPECTED TO CONTINUE TO INTENSIFY THROUGH THURSDAY EVENING BEFORE UPPER LEVEL WIND SHEAR BEGINS TO NEGATIVELY IMPACT THE SYSTEM. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. GULF OF TEHUANTEPEC GALE WARNING...A STRONG COLD FRONT THAT MOVED THROUGH THE CHIVELA PASS YESTERDAY HAS ALLOWED FOR COOL...DRY AIR TO MOVE OVER THE RELATIVELY WARM WATERS OF THE GULF OF TEHUANTEPEC. WINDS DIMINISHED TO GALE FORCE THIS AFTERNOON...AND WILL PERSIST THROUGH EARLY WED MORNING...THEN DIMINISH SLIGHTLY THROUGH LATE WED...BEFORE INCREASING AGAIN BRIEFLY TO GALE FORCE WED NIGHT/EARLY THU DURING THE PERIOD OF PEAK NOCTURNAL DRAINAGE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 08N74.5W TO 05N82W TO 09N97W...WHERE IT REMAINS FRACTURED FROM SANDRA...THEN RESUMES FROM 09N108W TO 05.5N117W...WHERE IT TRANSITIONS TO ITCZ... CONTINUING ON TO 08N130W TO 09N140W. SCATTERED MODERATE CONVECTION NOTED FROM 04N TO 09N E OF 82.5W...AND FROM 08N TO 13N BETWEEN 95W AND 103W. ...DISCUSSION... N OF 15N E OF 120W...A DEEP LAYER TROUGH CONTINUES TO DIG S-SE ACROSS THE FAR NE PACIFIC AND INLAND ACROSS THE WEST COAST OF THE UNITED STATES. AN ASSOCIATED SURFACE TROUGH WILL SHIFT EAST ACROSS BAJA CALIFORNIA NORTE AND THE NORTHERN PORTION OF THE GULF OF CALIFORNIA LATE TONIGHT THROUGH WED. WESTERLY WINDS OF 15-25 KT WILL FUNNEL THROUGH LOWER LYING GAPS ACROSS BAJA CALIFORNIA NORTE AND INTO THE NORTHERN GULF OF CALIFORNIA TONIGHT AND EARLY WED AHEAD OF THE TROUGH. A COLD FRONT WILL FOLLOW THIS...MOVING INTO THE WATERS OFF BAJA CALIFORNIA NORTE AND THE NORTHERN GULF OF CALIFORNIA BY LATE WED. THIS WILL BE ACCOMPANIED BY FRESH NW WINDS AND LONG PERIOD NW SWELL TO 9 FT. THE LEADING EDGE OF THE SWELL WILL REACH GUADALUPE ISLAND BY LATE WED...AND THE NORTHERN COAST OF BAJA CALIFORNIA SUR BY EARLY THU. MEANWHILE THE OUTER EDGE OF MIXED SWELL IN EXCESS OF 8 FT ASSOCIATED WITH THE APPROACHING SANDRA WILL MOVE NORTH OF THE REVILLAGIGEDO ISLANDS WED NIGHT...FOLLOWED BY THE OUTER PERIPHERY OF STRONG WINDS AHEAD OF SANDRA BY LATE THU. LOOKING AHEAD...SANDRA AND ITS ACCOMPANYING STRONG WINDS AND HIGH SEAS WILL SHIFT N TO NE AHEAD OF THE STALLING FRONT...GRAZING THE LOS CABOS AREA FRI INTO SAT BEFORE SHIFTING ACROSS THE MOUTH OF THE GULF OF CALIFORNIA AND MOVING INLAND NORTH OF MAZATLAN BY LATE SAT. S OF 15N E OF 110W...A TIGHT PRES GRADIENT BETWEEN HIGH PRES OVER THE SOUTHEAST UNITED STATES AND THE MONSOON TROUGH TO THE S HAS SET UP ACROSS CENTRAL AMERICA. A FRESH TO STRONG E-NE BREEZE HAS BEEN OCCURRING DOWNWIND OF THE GULF OF PAPAGAYO HAVE DIMINISHED THIS EVENING AND WILL FRESHENING AGAIN LATE TONIGHT THROUGH EARLY WED AFTERNOON. WEAKER GAP WIND FLOW IS EXPECTED EARLY THU. N TO NE WINDS OF 15-20 KT ARE SPILLING ACROSS PANAMA AND ACROSS THE GULF OF PANAMA THIS EVENING...WHERE SEAS ARE 4-6 FT. THESE CONDITIONS WILL PREVAIL OVERNIGHT BEFORE DIMINISHING BY AROUND NOON ON WED. ELSEWHERE SW SWELL WILL MOVE ACROSS THE EQUATOR AND MIX WITH SHORTER PERIOD NE SWELL EMERGING OUT OF TEHUANTEPEC. TO THE NW...THE 1009 MB POST-TROPICAL REMNANT LOW RICK WAS LOCATED NEAR 21.5N123.5W AND NEARLY STATIONARY. THERE IS NO SIGNIFICANT DEEP CONVECTION ASSOCIATED WITH THE LOW. STRONG UPPER LEVEL SOUTHWEST WINDS ARE EXPECTED TO REMAIN OVER THE SYSTEM FOR THE NEXT TWO DAYS. FRESH NE WINDS WILL PERSIST ACROSS THE NW SEMICIRCLE OF THE LOW THROUGH THIS EVENING...BUT WILL INCREASE AGAIN WEDNESDAY JUST AS THE LOW OPENS UP TO A TROUGH...AS THE PRESSURE GRADIENT INCREASES WITH AND AHEAD OF A SINKING COLD FRONT. THIS STRONG HIGH PRES CURRENTLY OVER THE NE PACIFIC IS BUILDING SOUTHWARD TOWARDS N PORTIONS OF THE DISCUSSION AREA...BEHIND A COLD FRONT CURRENTLY ALONG 31N. THIS COLD FRONT IS FORECAST TO REACH FAR N WATERS OVERNIGHT TONIGHT...WITH N- NW WINDS EXPECTED TO REACH 20-25 KT BEHIND THE FRONT OVER FAR NE WATERS BY EARLY WED MORNING. NW SWELL ASSOCIATED WITH THIS SYSTEM WILL PROPAGATE INTO THE AREA AHEAD OF THE FRONT...WITH SEAS IN THE 7- 9 FT RANGE EXPECTED OVER WATERS N OF 28N BETWEEN 118W AND 133W BY EARLY WED MORNING. SEAS WILL REACH AS HIGH AS 11 FT THROUGH EARLY THU MORNING AND THE SWELL PROPAGATES AS FAR S AS 21N. $$ STRIPLING