000
AXPZ20 KNHC 040231
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI OCT 04 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 10N85W TO 10N97W TO 12.5N105W TO 
1008 MB LOW PRES NEAR 12N110W TO 11N125W WHERE LOW LEVEL WINDS 
SUGGEST A TRANSITION TO ITCZ FROM 11N115W TO 11N140W. SCATTERED 
MODERATE CONVECTION WAS NOTED WITHIN 180 NM S OF TROUGH BETWEEN 
96W AND 105W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 150 
NM N AND 60 NM S OF TROUGH BETWEEN 110W AND 114W.

...DISCUSSION...

HIGH PRESSURE 1029 MB IS CENTERED N OF THE AREA NEAR 37N137W 
WITH ASSOCIATED RIDGE EXTENDING SE TO NEAR 20N112W. NW SWELLS 
CONTINUE TO PROPAGATE ACROSS THE FORECAST AREA WITH SEAS 8 FT OR 
GREATER COVERING MUCH OF THE AREA N OF 10N AND W OF 110W.

THE PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE CENTER MENTIONED 
ABOVE AND TROUGHING OVER THE WEST COAST OF THE UNITED STATES IS 
MAINTAINING GALE FORCE WINDS N OF THE AREA. NORTHERLY SWELLS 
GENERATED FROM THESE WINDS WILL CONTINUE TO PROPAGATE INTO THE 
NORTHERN PART OF THE FORECAST AREA OVER THE NEXT 24-36 HOURS. 
OVER THE NEXT COUPLE OF DAYS...THE AREA OF HIGH PRESSURE WILL 
WEAKEN AND MOVE NE WHILE THE TROUGH OVER THE WEST COAST WEAKENS. 
THIS WILL DECREASE WINDS N OF THE AREA ALLOWING FOR THE 
ASSOCIATED SWELLS TO DECREASE. BY SAT AFTERNOON SEAS OVER THE 
FORECAST AREA ASSOCIATED WITH THE SWELLS ARE EXPECTED TO SUBSIDE 
BELOW 8 FT. AS THE TROUGH WEAKENS...HIGH PRESSURE WILL BUILD 
OVER THE WESTERN UNITED STATES. THIS WILL RESULT IN NORTHERLY 
WINDS INCREASING TO 25 KT OVER THE FAR N PART OF THE GULF OF 
CALIFORNIA BY FRI AFTERNOON.

THE 1008 MB LOW NEAR 12N110W EMBEDDED WITHIN THE MONSOON TROUGH 
IS MOVING SLOWLY WESTWARD. SCATTERED MODERATE ISOLATED STRONG  
CONVECTION IS NOTED WITHIN 180 NM NW SEMICIRCLE OF THE LOW. THIS 
LOW IS EXPECTED TO CONTINUE TO MOVE WESTWARD OVER THE NEXT 48 
HOURS WITH NO SIGNIFICANT STRENGTHENING EXPECTED. 

$$
AL