000
AXPZ20 KNHC 251516
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE SEP 25 2012

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 
1500 UTC.

...SPECIAL FEATURES...
HURRICANE MIRIAM CENTERED NEAR 18.7N 114.5W AT 1500 UTC MOVING 
WNW OR 300 DEGREES AT 4 KT. MINIMUM CENTRAL PRESSURE IS 969 MB. 
MAXIMUM SUSTAINED WIND SPEED IS 85 KT WITH GUSTS TO 105 KT. SLOW 
WEAKENING IS FORECAST DURING THE NEXT 48 HOURS AS SOUTHWESTERLY 
SHEAR INCREASES. SWELLS GENERATED BY MIRIAM WILL AFFECT THE 
SOUTH AND WEST COASTS OF THE SOUTHERN BAJA PENINSULA DURING THE 
NEXT COUPLE OF DAYS. THESE SWELLS ARE LIKELY TO CAUSE LIFE 
THREATENING SURF AND RIP CURRENT CONDITIONS. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC 
FOR MORE DETAILS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 10N86W TO 12N95W TO 11N100W TO 13N107W. ITCZ 
FROM 13N130W TO 10N140W. SCATTERED MODERATE TO STRONG CONVECTION 
FROM 07N-16N BETWEEN 97W-105W.

...DISCUSSION...
UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 17N133W 
WITH RIDGE EXTENDING FROM THE CIRCULATION N TO 32N127W. A 55-75 
KT JET STREAM IS ADVECTING HIGH LEVEL MOISTURE FROM THE DEEP 
TROPICS INTO THE NW PORTION OF THE DISCUSSION AREA. OTHERWISE 
STRONG SUBSIDENCE WITH DRY AND STABLE AT THE MIDDLE AND UPPER 
LEVELS IS ACROSS THE AREA N OF 15N W OF 120W. A SHORTWAVE TROUGH 
WITH AXIS FROM 32N119W TO 25N123W. NO SIGNIFICANT WEATHER WITH 
THE TROUGH AS THE AIRMASS IS VARY DRY. ANOTHER ANTICYCLONIC 
CIRCULATION IS  OF THE COAST OF MEXICO CENTERED NEAR 18N105W. 
DIFFLUENT FLOW ALOFT S OF ANTICYLONE IS CONVECTION N OF THE 
MONSOON TROUGH FROM 97W-105W.

SURFACE RIDGE ACROSS THE AREA N OF 15N W OF 125W. AN AREA OF 
15-20 KT TRADE WINDS ON THE SOUTHERN PERIPHERY OF THE RIDGE FROM 
15N-19N W OF 128W. THE AERIAL EXTENT OF THE TRADES WILL DECREASE 
IN ABOUT 24 HOURS AS HIGH PRES MOVES WWD AND WEAKENS. 

TWO SWELL EVENTS PLUS SEAS GENERATED BY HURRICANE MIRIAM ARE 
IMPACTING THE REGIONAL WATERS. LARGE AND LONG PERIOD SWELLS FROM 
THE NW ARE SPREADING ACROSS THE NW WATERS RAISING SEAS TO AROUND 
9 FT MAINLY W OF A LINE FROM 30N120W TO 15N128W TO 08N140W. 
CROSS EQUATORIAL SW SWELLS ARE REACHING THE COAST OF MEXICO 
PARTICULARLY E OF 105W. THESE SWELL EVENTS WILL MERGE TODAY WITH 
SEAS OF 8 TO 11 FT AFFECTING MOST OF THE FORECAST WATERS W OF 
105W...EXCEPT HIGHER ASSOCIATED WITH HURRICANE MIRIAM.    

$$
DGS