000 AXPZ20 KNHC 091551 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI OCT 09 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1415 UTC. ...SPECIAL FEATURES... NEWLY-FORMED TROPICAL DEPRESSION EIGHTEEN-E WAS ANALYZED NEAR 11.1N 132.0W AT 1500 UTC OCT 09. THE DEPRESSION WAS MOVING W OR 280 DEG AT 12 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1008 MB. MAXIMUM SUSTAINED WINDS WERE 30 KT GUSTS 40 KT. CONVECTION HAS INCREASED MARKEDLY OVER THE PAST 24 HOURS. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 120 NM N AND W QUADRANTS OF THE CENTER AS WELL AS FROM 12N-15N BETWEEN 126W- 131W...WHILE SCATTERED MODERATE CONVECTION WAS WITHIN 60 NM E AND 120 NM S QUADRANTS OF THE CENTER. THE DEPRESSION IS EXPECTED TO BECOME A TROPICAL STORM BY THIS EVENING AND A HURRICANE BY SUN MORNING AS IT PASSES W OF THE FORECAST AREA. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE WAS ANALYZED ALONG 90W N OF 06N. THE WAVE WAS MOVING W AROUND 10-15 KT. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 210 NM EITHER SIDE OF THE WAVE FROM 09N- 12N...WITH SCATTERED MODERATE CONVECTION ELSEWHERE FROM 03N-10N BETWEEN 90W-96W. AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG THE WAVE...POSSIBLY AS EARLY AS SUN. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N78W TO 09N90W TO 08N96W TO 12N110W TO 12N128W...THEN CONTINUES FROM 10N135W TO 10N140W. SCATTERED MODERATE CONVECTION WAS FROM 02N-08N E OF 82W. SCATTERED MODERATE CONVECTION WAS BETWEEN 90 NM AND 330 NM N OF THE AXIS BETWEEN 110W-116W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 390 NM S OF THE AXIS BETWEEN 117W-124W. ...DISCUSSION... 1021 MB HIGH PRES CENTERED NEAR 31N127W EXTENDS A RIDGE AXIS SOUTHWESTWARD TO 21N140W. WINDS W OF THE RIDGE AXIS ARE A MODERATE SOUTHWESTERLY BREEZE IN RESPONSE TO A BROAD SURFACE TROUGH CENTERED NW OF THE AREA THAT INCLUDES THE REMNANTS OF OHO ON ITS LEADING EDGE. THESE WINDS WERE OBSERVED BY THE THE 0618 UTC ASCAT PASS. SEAS ARE BELIEVED TO BE 7-10 FT IN THE AREA N OF 26N W OF 130W PRIMARILY IN W-SW SWELL. HIGH PRES WILL SHIFT W-NW OVER THE AREA...ALLOWING WINDS TO DIMINISH AND SEAS TO SUBSIDE BELOW 8 FT BY THIS EVENING. BY SAT MORNING...SEAS WILL AGAIN RISE TO 7-9 FT IN NW WATERS AS A BATCH OF NW SWELL MOVES SOUTHEASTWARD THROUGH THE AREA. A SECOND RIDGE AXIS EXTENDS SOUTHEASTWARD FROM THE 1021 MB HIGH NEAR 31N127W THROUGH 23N123W TO THE ISLAS REVILLAGIGEDO. MODERATE TO FRESH N-NW WINDS ARE FOUND E OF THE RIDGE OFF THE PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA. THE HIGH PRES CENTER IS FORECAST TO TREK W-NW AS THE VAST UPPER LOW OVER NW MAINLAND MEXICO MOVES W-SW TO OFF THE BAJA CALIFORNIA PACIFIC COAST. THIS WILL SHIFT THE TIGHTEST PRESSURE GRADIENT WESTWARD ACROSS N WATERS. AN AREA OF FRESH...OCCASIONALLY STRONG...N WINDS WITH SEAS TO 8 FT IS EXPECTED GENERALLY IN THE AREA N OF 25N BETWEEN 120W-125W THIS EVENING THROUGH SAT NIGHT. THE DEEP LAYER RIDGING WILL WEAKEN SAT NIGHT INTO SUN...WITH WINDS AND SEAS EXPECTED TO DIMINISH BELOW ADVISORY CRITERIA BY SUN MORNING. THE VAST UPPER LOW EXPECTED TO MOVE THROUGH THE GULF OF CALIFORNIA AND THE BAJA CALIFORNIA PENINSULA WILL REFLECT A TROUGH AT THE SURFACE APPROXIMATELY 90-180 NM OFF THE BAJA CALIFORNIA COAST OVER THE WEEKEND. THE TROUGH WILL DEEPEN OVER THE WEEKEND...WITH A FRESH S-SE BREEZE EXPECTED BETWEEN THE TROUGH AND BAJA CALIFORNIA SUR BY SUN MORNING. SEAS ARE EXPECTED TO BUILD TO 8 FT BETWEEN BAJA CALIFORNIA SUR AND THE ISLAS REVILLAGIGEDO BY SUN MORNING. AN AREA OF SEAS TO 8 FT IN SW SWELL IS LINGERING OVER WATERS FROM 03N-07N BETWEEN 93W-101W ACCORDING TO AN 0854 ALTIMETER PASS. WHILE SEAS ARE FORECAST TO SUBSIDE BELOW 8 FT BY THIS AFTERNOON...A NEW BATCH OF SW SWELL WITH PERIODS AT OR ABOVE 20 SECONDS WILL REACH THE GALAPAGOS ISLANDS OVERNIGHT...MOVE ONTO THE COAST OF ECUADOR...COLOMBIA...AND CENTRAL AMERICA S OF CABO CORRIENTES MEXICO SUN MORNING. SEAS ALONG THE COAST SHOULD GENERALLY BE IN THE 4-6 FT RANGE. THIS SCENARIO COULD MAKE FOR HAZARDOUS CONDITIONS ENTERING AND EXITING PORTS AND INCREASE THE CHANCE FOR RIP CURRENTS. GAP WINDS... GULF OF TEHUANTEPEC...A PULSE OF FRESH N WINDS WITH SEAS TO 8 FT ARE EXPECTED TO DIMINISH THIS AFTERNOON. A NEW SURGE OF 20-30 KT WINDS WILL BEGIN EARLY SAT MORNING AS THE AFOREMENTIONED TROPICAL WAVE PASSES S OF TEHUANTEPEC AND RIDGING BUILDS OVER NE MEXICO. SEAS WILL BUILD TO 11 FT OVER THE WEEKEND. GULF OF PAPAGAYO...THE 0346 UTC ASCAT PASS SHOWED 20-25 KT E-NE WINDS DOWNWIND OF PAPAGAYO TO 87W. SEAS ARE BELIEVED TO BE TO 8 FT IN MIXED NE AND SW SWELL. NOCTURNAL DRAINAGE FLOW SHOULD HAVE ALLOWED THESE WINDS TO PERSIST THROUGH THIS MORNING. WINDS AND SEAS SHOULD DIMINISH TODAY AS THE TROPICAL WAVE ALONG 90W CONTINUES TO MOVE AWAY FROM THE AREA...SLACKENING THE PRESSURE GRADIENT. $$ SCHAUER