000
AXPZ20 KNHC 221553
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 22 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.

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

THE MONSOON TROUGH EXTENDS FROM 10N86W TO 13N96W TO 13N106W TO 
10N133W. ITCZ THEN EXTENDS FROM 10N136W TO 09N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS LOCATED WITHIN 120 NM OF 
TROUGH E OF 100W.  SCATTERED MODERATE CONVECTION IS OCCURRING 
WITHIN 60 NM OF TROUGH BETWEEN 113W AND 123W.

...DISCUSSION...

A WEAK COLD FRONT LIES ALONG 30N134W TO 30N140W IN THE NW CORNER 
OF OUR AREA OF RESPONSIBILITY.  THIS IS NOT LIKELY TO PROGRESS 
FARTHER SOUTH THAN ABOUT 27N BEFORE DISSIPATING IN A DAY OR 
TWO.  NO SIGNIFICANT DEEP CONVECTION IS CURRENTLY OBSERVED NEAR 
THE FRONT...THOUGH SCATTERED SHOWERS ARE LIKELY WITHIN 120 NM OF 
IT.

DISORGANIZED SHOWERS AND THUNDERSTORMS ALONG THE MONSOON TROUGH 
E OF 100W ARE ASSOCIATED A LOW-LEVEL VORTICITY MAXIMUM NEAR 
10N98W.  THIS FEATURE IS ROBUSTLY SPUN UP BY THE 06Z GFS 
DETERMINISTIC GLOBAL MODEL TO A TROPICAL CYCLONE BY WEDNESDAY.  
HOWEVER...THE REMAINING MODELS...INCLUDING THE GFS ENSEMBLE... 
DELAY THE DEVELOPMENT OF A SYSTEM UNTIL FRIDAY...AT THE 
EARLIEST.  THUS EMPHASIS IS PLACED UPON THE ECMWF...UKMET... 
NOGAPS...AND GFS ENSEMBLE FOR THE SURFACE WIND AND PRESSURE 
PREDICTIONS.  LIKEWISE...THE OUTPUT FROM THE GFS-BASED WAVEWATCH 
MODEL IS SUBSTANTIALLY REDUCED.  INSTEAD OF 12 FOOT SEAS BY 48 
HOURS...THE PEAK IS SET AT 9 FT IN THE SW MONSOONAL FLOW SOUTH 
OF 11N.  SIMILARLY...THE 26 FT PEAK SIGNIFICANT WAVE HEIGHT 
FRIDAY MORNING IS REDUCED TO JUST 12 FT.

A WEAK GULF OF TEHUANTEPEC GAP WIND EVENT IS CURRENTLY OCCURRING 
WITH WINDS UP TO 30 KT AS OBSERVED FROM AN OSCAT SATELLITE 
SCATTEROMETER PASS EARLY THIS MORNING.  THESE WINDS SHOULD 
CONTINUE...THOUGH WEAKER IN THE AFTERNOON AND EARLY 
EVENING...THROUGH THURSDAY BEFORE DIMINISHING COMPLETELY ON 
FRIDAY.

BUILDING SURFACE HIGH PRESSURE SEVERAL HUNDRED MILES WEST OF THE 
UNITED STATES-MEXICO BORDER WILL ENHANCE THE PRESSURE GRADIENT 
...AND THUS THE NW WINDS...ALONG THE SOUTHERN CALIFORNIA AND 
NORTHERN BAJA CALIFORNIA COASTS.  WINDS UP TO 25 KT AND SEAS TO 
8 FT ARE EXPECTED BY WEDNESDAY MORNING.  THESE SHOULD CONTINUE 
BUT REMAIN BELOW GALE FORCE THROUGH FRIDAY.

NO SIGNIFICANT LONG-PERIOD SWELL EVENTS ARE EXPECTED IN OUR AREA 
OF RESPONSIBILITY OVER THE NEXT SEVERAL DAYS.

$$
LANDSEA