000
AXPZ20 KNHC 252149
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED SEP 25 2013

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 
2100 UTC.

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

THE MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO LOW PRES NEAR 
09N86W TO LOW PRES NEAR 16N99W TO 13N110W TO LOW PRES NEAR 
14N123W TO 09N140W. NO ITCZ AXIS IS PRESENT E OF 140W. NUMEROUS 
MODERATE AND SCATTERED STRONG CONVECTION IS N OF 07N E OF 82W... 
SCATTERED MODERATE CONVECTION IS WITHIN 150 NM W OF THE MONSOON 
TROUGH BETWEEN 89W AND 91W...WITHIN 180 NM SW OF MEXICO BETWEEN 
98W AND 106W...AND ALSO WITHIN 150 NM S OF THE MONSOON TROUGH W 
OF 132W. 

...DISCUSSION...

SATELLITE WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL ANTICYCLONE  
LOCATED NEAR SOUTHERN BAJA CALIFORNIA AT 24N111W WITH RIDGING 
COVERING THE CENTRAL PORTION OF THE WATERS. DRY AND STABLE 
CONDITIONS ARE PRESENT N OF A LINE FROM 22N106W TO 20N125W TO 
13N140W. TO THE SW OF THE ANTICYCLONE...AN INVERTED SHORTWAVE 
UPPER LEVEL TROUGH EXTENDS FROM NEAR 20N128W TO 08N131W WITH 
ISOLATED TO WIDELY SCATTERED SHOWERS POSSIBLE WITHIN 180-300 NM 
E OF THE TROUGH. TO THE E OF THE TROUGH AND SE OF THE 
ANTICYCLONE...FAIRLY DEEP LAYERED EASTERLY FLOW IS NOTED. THIS 
FLOW PATTERN CONTINUES TO ADVECT UPPER LEVEL DEBRIS MOISTURE 
FROM CONVECTION ALONG THE COAST OF SOUTHERN MEXICO...AS WELL AS 
JUST INLAND AND S OF SOUTHEASTERN MEXICO AS IS DESCRIBED IN THE 
CONVECTION SECTION ABOVE. 
 
AT THE SURFACE...A NEARLY STATIONARY 1031 MB HIGH PRES IS WELL 
NW OF THE DISCUSSION AREA NEAR 39N146W WITH A RIDGE STRETCHING 
SE THROUGH 32N135W TO 26N124W. A WEAK TROUGH EXTENDS JUST SE OF 
THE RIDGE FROM NEAR 29N118W TO 24N125W. THE TIGHT PRES GRADIENT 
BETWEEN THE RIDGE AND TROUGH IS RESULTING IN NW 25-30 KT WINDS 
JUST N OF THE NE PART OF THE AREA. THESE WINDS ARE FORECAST TO 
STRENGTHEN TO MINIMAL GALE INTENSITY N OF 32N THIS EVENING. THE 
RESULTANT SWELLS WITH PERIODS OF 15-18 SECONDS WILL PROPAGATE SE 
INTO MUCH OF THE NE AND N CENTRAL SECTIONS OF THE AREA THROUGH 
THE NEXT 48 HOURS...PRODUCING SEAS OF 10-13 FT THIS EVENING N OF 
26N BETWEEN 120W AND 128W...AND 8 FT OR GREATER ACROSS THE 
REMAINDER OF THE WATERS N OF 21N/22N W OF 116W. THE NW SWELLS 
WILL CONTINUE TO SEEP TO THE SE-S REACHING TO NEAR 08N BY FRI 
AFTERNOON WHILE HEIGHTS DECAY TO 8-10 FT AT MOST.

1008 MB LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 16N99W. 
THIS LOW IS UNDERNEATH AN AREA OF UPPER EASTERLY SHEAR WITH THE 
MAJORITY OF THE DEEP CONVECTION DISPLACED TO THE S-SW OF THE LOW 
LEVEL CIRCULATION. ASSOCIATED WINDS ARE MODERATE TO FRESH WITH 
SEAS CURRENTLY LESS THAN 8 FT. THE LOW IS FORECAST TO MOVE TO 
THE W-NW DURING THE NEXT 48 HOURS JUST S OF THE COAST OF MEXICO. 
ADDITIONAL HEAVY RAINS MAY SPREAD OVER AREAS OF SW MEXICO THAT 
ARE ALREADY WELL SATURATED DUE TO PREVIOUS TROPICAL SYSTEMS... 
WITH THE RISK OF FLASH FLOODING AND MUDSLIDES PARTICULARLY 
ACROSS SOUTHERN AND SOUTHWESTERN MEXICO THROUGH THE END OF THE 
WEEK.

1008 MB LOW PRES IS WELL TO THE W...ALSO EMBEDDED IN THE MONSOON 
TROUGH...NEAR 14N123W. FRESH TO STRONG WINDS AND 8-9 FT SEAS ARE 
OCCURRING WITHIN 150 NM IN THE NW AND N QUADRANTS...AND ALSO 
WITHIN 120 NM IN THE SE QUADRANT OF THE LOW. THE LOW IS FORECAST 
TO MOVE E REACHING 14N119W WHILE WEAKENING TO 1011 MB IN 24 
HOURS...THEN WILL LIKELY DISSIPATE SHORTLY THEREAFTER.

CROSS-EQUATORIAL SE SWELL IS IMPACTING THE FAR SW WATERS WITH 8-
9 FT SEAS S OF A LINE FROM 00N110W TO 06N120W TO 06N128W TO 
04N140W. THIS AREA OF SE SWELL WILL GRADUALLY DECAY TO LESS THAN 
8 FT BY FRI AFTERNOON.

$$
LEWITSKY