000
AXPZ20 KNHC 302150
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.               

...SPECIAL FEATURES...

TROPICAL DEPRESSION MARTY WAS CENTERED NEAR 16.3N 103.0W AT 
30/2100 UTC OR 178 NM S-SE OF MANZANILLO MEXICO MOVING W AT 5 
KT. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1005 MB. MAXIMUM 
SUSTAINED WIND SPEED WAS 25 KT WITH GUSTS TO 35 KT. 20-25 KT 
WINDS WERE FOUND WITHIN 60 NM N SEMICIRCLE ACCORDING TO THE 
LATEST ASCAT PASS. SCATTERED MODERATE CONVECTION WAS WITHIN 90 
NM N 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 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 TONIGHT. 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 12N120W. 
SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 120 NM N AND 
SW QUADRANTS OF THE LOW WITH SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION ELSEWHERE FROM 08N-14N BETWEEN 117W-122W. THE 
LOW IS EXPECTED SLOWLY DRIFT N 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 THU AND BEGIN TO SUBSIDE ON FRI. 

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

THE MONSOON TROUGH WAS ANALYZED FROM 08N83W TO 11N95W...THEN 
CONTINUED FROM 15N105W TO 14N116W TO LOW PRES NEAR 12N120W 1007 
MB TO 08N130W TO 10N140W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION WAS S OF THE AXIS TO 04N BETWEEN 86W-93W AS 
WELL AS FROM 02N-06N BETWEEN 80W-88W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION WAS FROM 10N-14N BETWEEN 93W-98W. 
SCATTERED MODERATE CONVECTION WAS BETWEEN 90 NM AND 300 NM 
EITHER SIDE OF THE AXIS BETWEEN 123W-128W. 

...DISCUSSION...

A SURFACE RIDGE EXTENDS ACROSS THE AREA FROM 1017 MB HIGH PRES 
NEAR 28N127W TO THE ISLAS REVILLAGIGEDO. RIDGING HERE IS BEING 
COMPROMISED BY A WEAKENING STATIONARY FRONT ANALYZED FROM 
32N126W TO 22N140W. 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. 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 FRI 
AFTERNOON IN MIXED SE AND NW SWELL.

GAP WINDS...                                                     
GULF OF TEHUANTEPEC...1017 MB HIGH PRES WAS ANALYZED OVER 
VERACRUZ THIS AFTERNOON. HIGH PRES IS EXPECTED TO CONTINUE 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 
EXPECTED TO BEGIN THIS EVENING AND 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 AFTERNOON. SEAS SHOULD BUILD TO AS HIGH AS 11 FT.
  
$$
SCHAUER