000 AXPZ20 KNHC 300316 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED SEP 30 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 0130 UTC. ...SPECIAL FEATURES... TROPICAL STORM MARTY REMAINS STATIONARY CENTERED NEAR 16.3N 101.2W AT 30/0300 UTC. ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB. MAXIMUM SUSTAINED WINDS WERE 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE TO STRONG CONVECTION WAS OVER WATERS WITHIN 90 NM NE QUADRANT AND 60 NM NW QUADRANT WITH SCATTERED MODERATE CONVECTION ELSEWHERE WITHIN N OF 16N BETWEEN 98W-103W. DEEP TROPICAL MOISTURE AND HEAVY RAIN SPREADING INLAND ACROSS SW MEXICO MAY PRODUCE LOCALIZED FLASH FLOODING AND MUDSLIDES. MARTY IS EXPECTED TO BECOME A TROPICAL DEPRESSION BY WED EVENING. LARGE SWELL FROM MARTY MAY CAUSE DANGEROUS SURF CONDITIONS AND RIP CURRENTS. REFER TO LATEST NHC FORECAST/ADVISORY AND PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC MIATCPEP2/WTPZ32 KNHC FOR MORE DETAILS. A 1008 MB LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR 12N119W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 180 NM S QUADRANT WITH SCATTERED MODERATE CONVECTION ELSEWHERE WITHIN 90 NM OF CENTER. THE LOW IS EXPECTED TO DRIFT N-NE IN ENHANCED MONSOONAL FLOW THROUGH WED AS IT SLOWLY DEEPENS. BY THU... ENVIRONMENTAL CONDITIONS WILL BECOME MORE FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT. CROSS-EQUATORIAL SE SWELL MIXING WITH SW WIND WAVES S OF THE MONSOON TROUGH AXIS WILL PRODUCE 8-9 FT SEAS S OF THE LOW ACROSS S CENTRAL WATERS THE NEXT COUPLE OF DAYS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH WAS ANALYZED FROM 10N84W TO 10N95W...THEN CONTINUES FROM LOW PRES NEAR 14N108W 1008 MB TO LOW PRES NEAR 12N119W 1008 MB TO 07N130W TO 13N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS N OF 05N E OF 85W. SCATTERED MODERATE CONVECTION WAS WITHIN 150 NM S OF THE AXIS BETWEEN 106W-114W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 330 NM N OF THE AXIS W OF 138W. ...DISCUSSION... A SURFACE RIDGE EXTENDS ACROSS THE AREA FROM NEAR 32N122W THROUGH 29N124W TO 16N106W. RIDGING HERE WILL SHIFT SLIGHTLY E TONIGHT AND WILL BRIEFLY BE COMPROMISED WED BY AN APPROACHING COLD FRONT JUST N OF THE AREA. THE PRESSURE GRADIENT ACROSS THE BAJA CALIFORNIA PENINSULA SHOULD BRIEFLY ALLOW FOR FRESH N-NW WINDS ALONG THE PACIFIC COAST TONIGHT AND WED NIGHT AS WELL AS IN THE SOUTHERN GULF OF CALIFORNIA TONIGHT. THIS COLD FRONT BECOMES STATIONARY S OF 32N. THE STATIONARY FRONT...ANALYZED FROM 32N127W TO 20N140W THIS EVENING...WILL BECOME DIFFUSE DURING THE NEXT 24 HOURS. SEAS TO 7 FT IN THE NW CORNER OF DISCUSSION AREA WILL SUBSIDE TONIGHT. DESPITE THE WEAKENING FRONT...THE SURFACE RIDGE WILL NOT BUILD APPRECIABLY OVER NW WATERS AS A STRONGER COLD FRONT WELL NW OF THE AREA WILL WEAKEN THE 1021 MB HIGH PRES BEHIND IT NEAR 33N152W. GAP WINDS... GULF OF TEHUANTEPEC...HIGH PRES BUILDING OVER THE WESTERN GULF OF MEXICO WILL INCREASE THE PRES GRADIENT ACROSS CHIVELA PASS BY EARLY THU. A SURGE OF STRONG TO NEAR GALE FORCE N-NE WINDS IS EXPECTED TO STRETCH THROUGH THE GULF OF TEHUANTEPEC IN THE EARLY MORNING HOURS AND WEAKEN A NOTCH BY THU AFTERNOON WHEN NOCTURNAL DRAINAGE FLOW IS NO LONGER ENHANCING THE WIND. SEAS SHOULD BUILD AS HIGH AS 11 FT. $$ SCHAUER