000 AXPZ20 KNHC 252217 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2130 UTC. ...SPECIAL FEATURES... HURRICANE SANDRA WAS CENTERED NEAR 13.0N 109.9W AT 2100 UTC...OR ABOUT 485 NM SW OF MANZANILLO MEXICO AND ABOUT 600 NM S OF THE SOUTHERN TIP OF THE BAJA CALIFORNIA PENINSULA. SANDRA IS MOVING NW OR 325 DEGREES AT 7 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE WAS 967 MB. MAXIMUM SUSTAINED WINDS HAVE CONTINUED TO INCREASE...AND ARE NOW 100 KT WITH GUSTS TO 120 KT...MAKING SANDRA A DANGEROUS CATEGORY THREE HURRICANE. SOME ADDITIONAL STRENGTHENING OS SANDRA IS POSSIBLE DURING THE NEXT 24 HOURS ASIT MOVES NORTHWARD AND REMAINS OVER WARM WATERS. CURRENTLY NUMEROUS STRONG CONVECTION IS OBSERVED WITHIN 75 NM ACROSS THE SE AND 45 NM NW SEMICIRCLES...WHILE SCATTERED MODERATE TO STRONGCONVECTION IS OCCURRING IN BANDS ELSEWHERE WITHIN 500 NM ACROSS THE NE SEMICIRCLE AND 330 NM SE QUADRANT. SANDRA IS FORECAST TO TURN TOWARD THE NORTH NORTHEAST THURSDAY AND ACCELERATE TOWARD THE SOUTHERN PORTIONS OF THE GULF OF CALIFORNIA AND BAJA CALIFORNIA PENINSULA...AND LOCAL INTERESTS SHOULD MONITOR THE PROGRESS OF SANDRA AS WATCHES AND WARNINGS MAY BE REQUIRED LATER TONIGHT. MARINE CONDITIONS ACROSS THE PACIFIC WATERS OF BAJA CALIFORNIA SUR WILL DETERIORATE RAPIDLY THURSDAY THROUGH AND FRIDAY AS SOUTHEAST SWELL FROM SANDRA BEGINS TO MERGE WITH LONG PERIOD NORTHERLY SWELL MOVING INTO THE AREA FROM THE NORTHEAST PACIFIC. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. GULF OF TEHUANTEPEC GALE WARNING...NORTHERLY WINDS BLOWING ACROSS THE GULF OF TEHUANTEPEC HAVE DIMINISHED TO 30 KT THIS AFTERNOON...BUT ARE EXPECTED TO BRIEFLY INCREASE TONIGHT TO MINIMAL GALE FORCE DURING THE MAXIMUM NOCTURNAL DRAINAGE PERIOD...LATE TONIGHT THROUGH SUNRISE ON THU. ALTHOUGH THE PRESSURE GRADIENT WILL GRADUALLY WEAKEN ACROSS SOUTHERN MEXICO OVER THE NEXT SEVERAL DAYS...THE MAXIMUM DRAINAGE FLOW SHOULD REACH AROUND 30 KT EACH OF THE NEXT SEVERAL NIGHTS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 08N78W TO 06N83W TO 07N100W...THEN RESUMES FROM 10N109W TO 03N119W. ITCZ AXIS FROM 03N119W TO BEYOND 02N140W. NO SIGNIFICANT CONVECTION IS NOTED OUTSIDE OF THE CIRCULATION OF SANDRA. ...DISCUSSION... A COLD FRONT ENTERS THE DISCUSSION AREA AT 30N116.5W AND EXTENDS THROUGH 27N130W TO 30N138W. NORTHERLY WINDS AT 15-20 KT ACCOMPANY THE FRONT TO THE S OF 32N...WITH LONG PERIOD NW SWELL MOVING INTO THE AREA AND OUTRUNNING THE COLD FRONT DURING THE NEXT 48 HOURS. SEAS TO 8-10 FT IN NW SWELL CURRENTLY PREVAIL TO THE N OF THE FRONT. ALTHOUGH THE FRONT IS EXPECTED TO CONTINUE S AND BECOME ILL DEFINED BY LATE THU...THE PRESSURE GRADIENT WITHTHE FRONT WILL TIGHTEN...INCREASING THE NE FLOW TO 20-25 KT ACROSS THE WATERS FROM 19-23N BETWEEN 122-132W. BY THEN THE LONG PERIOD NW SWELL WILL PROPAGATE S ACROSS THE DISCUSSION WATERS N OF 18N W OF 118W BY LATE THU WITH SEAS BUILDING TO 8-11 FT. AS MENTIONED ABOVE...THE NW SWELL WILL MIX WITH THE BROAD MIX OF SOUTHEASTERLY SWELL ASSOCIATED WITH TROPICAL CYCLONE SANDRA ON THU THROUGH FRI ACROSS THE WATERS FROM ABOUT 13-27N BETWEEN 112- 120W. A 1010 MB LOW IS ANALYZED AT 21N125W...AND IS THE REMNANTS OF TROPICAL CYCLONE RICK. BROKEN TO LOCALLY OVERCAST STRATO CUMULUS CLOUDS PREVAIL ACROSS THE N SEMICIRCLE OF THE CENTER. ALTHOUGH THE LOW IS FORECAST TO OPEN UP TO A TROUGH BY TONIGHT...HIGH PRESSURE BUILDING SOUTHWARD INTO THE REGION WITH THE COLD FRONT WILL INCREASE THE PRESSURE GRADIENT TO THE N AND NW OF THE TROUGH TONIGHT...AND INCREASE NE WINDS AHEAD OF THE SINKING COLD FRONT TO 20N. GAP WINDS... GULF OF PAPAGAYO...A TIGHT PRESSURE GRADIENT WILL CONTINUE TO SUPPORT PULSES OF NE-E 20-25 KT WINDS TONIGHT AND AGAIN ON THU NIGHT WITH SEAS BUILDING TO 8 FT DOWNSTREAM OF THE GULF OF PAPAGAYO TO NEAR 09N90W. $$ STRIPLING