000
AXPZ20 KNHC 102104
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2135 UTC WED OCT 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 11N86W TO 12N92W TO LOW PRES 
1009 MB NEAR 12N99W TO 11N128W. THE ITCZ EXTENDS FROM 11N128W TO 
BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
WAS NOTED WITHIN 120 NM EITHER SIDE OF MONSOON TROUGH AXIS 
BETWEEN 85W AND 107W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 150 NM S OF MONSOON TROUGH AXIS 
BETWEEN 116W AND 120W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 60 NM OF ITCZ AXIS W OF 135W. 

...DISCUSSION...

W OF 110W...A WEAK COLD FRONT EXTENDS FROM SOUTHERN CALIFORNIA 
AND ENTERS THE FORECAST AREA NEAR 29N117W EXTENDING TO 25N128W 
THEN TO 30N134W. THE FRONT WILL MAKE ONLY SLOW PROGRESS TO THE 
SOUTHEAST BEFORE STALLING AND DISSIPATING AS THE PARENT UPPER 
LOW CURRENTLY OFF THE COAST OF CENTRAL CALIFORNIA LIFTS OUT OVER 
THE NEXT 48 HOURS. A WEAK SURFACE RIDGE EXTENDS ACROSS THE AREA 
TO THE SOUTH OF THE COLD FRONT WHILE A DISSIPATING SURFACE 
LOW...REMNANTS OF OLIVIA...IS CENTERED NEAR 13N127W. THE 
PRESSURE GRADIENT BETWEEN THE RIDGE AND THE LOW PRESSURE CENTER 
IS MAINTAINING FRESH TO LOCALLY STRONG WINDS IN THE NW QUADRANT 
OF THE LOW. THE LOW WILL DISSIPATE BY THU. 

NW SWELL CONTINUES TO PROPAGATE INTO THE AREA FROM THE N CENTRAL 
PACIFIC. WAVEWATCH...EC WAVE AND UKMET WAVE OUTPUT INDICATE 
SIGNIFICANT WAVE HEIGHTS REACHING 8 TO 11 FT IN MIXED NW AND NE 
SWELL OVER MUCH OF THE AREA N OF 08N AND W OF 125W. 

E OF 110W...
AS IS TYPICAL WITHIN A MONSOON TROUGH...THERE ARE A FEW WEAK 
VORTICITY CENTERS EMBEDDED WITHIN THE FEATURE. MODEL GUIDANCE IS 
SHOWING A WIND PULSE TO 20 KT THROUGH THE GULF OF TEHUANTEPEC 
DUE TO DRAINAGE EFFECTS LATE TONIGHT AND EARLY TOMORROW MORNING. 
A SLIGHTLY STRONGER AND MORE PERSISTENT PULSE WILL REPEAT THU 
NIGHT INTO FRI MORNING AIDED BY REINFORCING HIGH PRES IN THE 
GULF OF MEXICO. MODEL GUIDANCE CONTINUES TO INDICATE THAT THIS 
MAY PROVIDE ADDED IMPETUS FOR THE FORMATION OF A TROPICAL 
CYCLONE ASSOCIATED WITH ONE OF THESE VORTICITY CENTERS EMBEDDED 
WITHIN THE MONSOON TROUGH. THIS AREA WILL CONTINUE TO BE CLOSELY 
MONITORED OVER THE NEXT COUPLE OF DAYS. 
 
$$
AL