000
AXPZ20 KNHC 301517
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.               

...SPECIAL FEATURES...

TROPICAL DEPRESSION MARTY CENTERED NEAR 16.2N 102.6W AT 30/1500 
UTC OR 196 NM SSE OF MANZANILLO MEXICO MOVING W AT 5 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED 
WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SCATTERED MODERATE 
WITHIN 90 NM N QUADRANT. MARTY WILL CONTINUE TO PRODUCE HEAVY 
RAINFALL IN THE MEXICAN STATE OF GUERRERO FROM THE SIERRA MADRE 
DEL SUR MOUNTAINS TOWARDS THE COAST WITH LIFE-THREATENING FLASH 
FLOODS AND MUDSLIDES POSSIBLE. A STORM SURGE IS EXPECTED TO 
PRODUCE COASTAL FLOODING IN AREAS OF ONSHORE FLOW AND SWELLS 
GENERATED BY MARTY WILL CAUSE LIFE-THREATENING SURF AND RIP 
CURRENTS ALONG PORTIONS OF SOUTHERN MEXICO. MARTY IS FORECAST TO 
CONTINUE TO WEAKEN AND WILL BECOME A REMNANT LOW BY 24 HOURS. 
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 11N119W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 240 NM SW QUADRANT.   
THE LOW IS EXPECTED TO DRIFT N IN ENHANCED MONSOONAL FLOW 
THROUGH TODAY AS IT SLOWLY DEEPENS. BY THU...ENVIRONMENTAL 
CONDITIONS WILL BECOME MORE FAVORABLE FOR TROPICAL CYCLONE 
DEVELOPMENT. CROSS-EQUATORIAL SOUTHERLY 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 DURING THE NEXT COUPLE 
OF DAYS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

THE MONSOON TROUGH AXIS EXTENDS FROM 09N82W TO 10N90W THEN 
RESUMES FROM 15N104W TO LOW PRES NEAR 11N119W 1007 MB TO 11N126W 
TO 09N134W TO 11N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS WITHIN 300 NM S OF COAST OF CENTRAL AMERICA E OF 
91W...WITHIN 180 NM N OF AXIS BETWEEN 110W AND 117W...AND WITHIN 
360 NM S OF AXIS BETWEEN 121W AND 132W. 

...DISCUSSION...

A SURFACE RIDGE EXTENDS ACROSS THE AREA FROM 1018 MB HIGH PRES  
W OF THE DISCUSSION WATERS NEAR 32N145W THROUGH 27N135W. A WEAK 
STATIONARY FRONT IS FURTHER E FROM 30N128W TO 20N140W. THE FRONT 
IS FORECAST TO BECOME DIFFUSE DURING THE NEXT 24 HOURS WHILE 
SEAS UP TO 7 FT W OF IT GRADUALLY SUBSIDE. THE RIDGE WILL 
GRADUALLY STRENGTHEN BY THE END OF THE WEEK ALLOWING FOR FRESH 
WINDS TO DEVELOP OFF OF THE CALIFORNIA COAST AND ALONG THE 
NORTHERN PORTION OF THE BAJA CALIFORNIA PENINSULA. THESE WINDS 
WILL BUILD SEAS TO 8 FT N OF 27N E OF 118W BY 42 HOURS.

GAP WINDS...                                                     
GULF OF TEHUANTEPEC...HIGH PRES BUILDING OVER THE WESTERN GULF 
OF MEXICO WILL INCREASE THE PRES GRADIENT ACROSS THE CHIVELA 
PASS TONIGHT. A SURGE OF STRONG TO NEAR GALE FORCE N-NE WINDS IS 
EXPECTED TO STRETCH THROUGH THE GULF OF TEHUANTEPEC TONIGHT
...WITH THE STRONGEST WINDS EXPECTED IN THE EARLY MORNING HOURS 
WHEN NOCTURNAL DRAINAGE FLOW OCCURS. SEAS ARE FORECAST BY THE 
LATEST TAFB-NWPS WAVE MODEL RUN TO BUILD UP TO 10-11 FT BY THU 
MORNING.
  
$$
FORMOSA