000 AXPZ20 KNHC 010313 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU OCT 01 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 0115 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION MARTY WAS CENTERED NEAR 16.6N 103.6W AT 01/0300 UTC MOVING W-NW AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1006 MB. MAXIMUM SUSTAINED WIND SPEED 25 KT WITH GUSTS TO 35 KT. 20-25 KT WINDS WERE FOUND WITHIN 60 NM IN THE N SEMICIRCLE ACCORDING TO THE LATEST ASCAT PASS. SCATTERED MODERATE CONVECTION WAS WITHIN 75 NM IN THE NE QUADRANT. RAINS OVER MEXICO WILL DIMINISH AS THE CENTER OF MARTY CONTINUES W AND MARTY WEAKENS OVER THE NEXT DAY OR SO. MARTY HAS ALREADY PRODUCED HEAVY RAINFALL AND FLOODING IN THE MEXICAN STATE OF GUERRERO FROM THE SIERRA MADRE DEL SUR MOUNTAINS TOWARDS THE COAST. SWELLS ASSOCIATED WITH MARTY HAVE BEGUN TO SUBSIDE AND WILL DIMINISH THROUGH THU. MARTY IS FORECAST TO WEAKEN TO A REMNANT LOW OVERNIGHT BY MORNING. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. A 1007 MB LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR 11N120W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 210 NM NW QUADRANT WITH SCATTERED MODERATE CONVECTION ELSEWHERE WITHIN 210 NM SW SEMICIRCLE. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS ELSEWHERE FROM 11N-15N BETWEEN 123W-129W. THE LOW IS EXPECTED TO SLOWLY MOVE NORTHWARD OVER THE NEXT DAY OR SO. ENVIRONMENTAL CONDITIONS SHOULD BECOME MORE FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT. CROSS-EQUATORIAL SOUTHEASTERLY SWELL MIXING WITH SW WIND WAVES S OF THE MONSOON TROUGH AXIS WILL PRODUCE 8-10 FT SEAS S OF THE LOW ACROSS S CENTRAL WATERS THROUGH FRI. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH WAS ANALYZED FROM 08N83W TO 12N96W...THEN CONTINUES FROM 15N105W TO 12N111W TO 13N116W TO LOW PRES NEAR 11N120W 1007 MB TO 08N134W TO 10N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 120 NM OF COAST BETWEEN 81W-86W. SCATTERED MODERATE BETWEEN 120 NM AND 330 NM S OF THE AXIS BETWEEN 82W-94W. SCATTERED MODERATE N OF AXIS TO 15N BETWEEN 114W-119W. ...DISCUSSION... A SURFACE RIDGE EXTENDS ACROSS THE AREA FROM 32N124W TO NEAR 28N125W TO 17N110W. RIDGING HERE IS BEING COMPROMISED BY A WEAKENING STATIONARY FRONT ANALYZED FROM 32N126W TO 21N140W. THE STATIONARY FRONT WILL BECOME DIFFUSE DURING THE NEXT 24 HOURS...ALLOWING RIDGING TO BUILD BEHIND IT OVER N WATERS. THIS WILL INCREASE THE PRES GRADIENT ALONG THE BAJA CALIFORNIA PENINSULA WITH FRESH N-NW WINDS EXPECTED THU EVENING INTO FRI MORNING OFF THE PACIFIC COAST OF BAJA CALIFORNIA NORTE. AS A RESULT...SEAS WILL BUILD TO 8 FT N OF 28N BETWEEN 115W AND 118W LATE THU NIGHT THROUGH FRI MORNING. AT THE SAME TIME...TROUGHING WILL BUILD JUST W OF THE AREA...DIRECTING FRESH SE TO S WINDS OVER THE NW WATERS FRI. SEAS ARE EXPECTED TO BUILD TO 8 TO 10 FT HERE BY EARLY FRI IN MIXED SE AND NW SWELL AND SPREAD ACROSS THE AREA N OF 23N W OF 132W THROUGH FRI EVENING. GAP WINDS... GULF OF TEHUANTEPEC...HIGH PRES IS EXPECTED TO BUILD OVER THE WESTERN GULF OF MEXICO OVER THE NEXT FEW DAYS. THE PRES GRADIENT ACROSS CHIVELA PASS HAS ALREADY BEGUN TO TIGHTEN. A SURGE OF STRONG TO NEAR GALE FORCE N-NE WINDS IS BELIEVED TO HAVE BEGUN THIS EVENING AND WILL STRETCH THROUGH THE GULF OF TEHUANTEPEC TO AS FAR DOWNSTREAM AS 13N96W OVERNIGHT. THESE CONDITIONS WILL CONTINUE THROUGH THE END OF THE FORECAST PERIOD FRI EVENING. SEAS MAY BUILD AS HIGH AS 12 FT IN MIXED NE AND SE SWELL. $$ SCHAUER