000
AXPZ20 KNHC 210958
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THUD OCT 21 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
AXIS ALONG 09N84W TO 08N140W.  SCATTERED MODERATE CONVECTION 
WITHIN 120 NM S OF AXIS E OF 98W AND WITHIN 120 NM N OF AXIS W 
OF 134W.

...DISCUSSION...
VERY BROAD AND WELL ANCHORED UPPER LEVEL ANTICYCLONE CENTERED AT 
13N117W WITH RIDGE EXTENDING FROM GULF OF TEHUANTEPEC TO 
12N140W.  WEAK UPPER LEVEL UPSTREAM TROUGH ENTERS NW CORNER OF 
BASIN BUT BLOCKED FROM FURTHER S INCURSION BY RIDGE.  TROUGH 
LIFT NE PULLING AWAY SUPPORT OF COLD FRONT AND LETTING IT 
DISSIPATE.  SWATH OF TROPICAL MOISTURE...ITCZ CONVECTIVE DEBRIS
...TRAPPED BETWEEN RIDGE AND TROUGH ADVECTS NE BY 100 KT JET 
CORE INTO CYCLONIC VORTEX NEAR 33N114W.  UPPER DIVERGENT FLOW E 
OF VORTEX PROMPTING LARGE AREA OF PRECIPITATION OVER NEW MEXICO 
AND WESTERN TEXAS.  

LARGE AREA OF MODERATE TO STRONG SUBSIDING AIR MASS MAINTAIN 
MOST OF E PAC VERY DRY.  ITCZ UNABLE TO CAPTURE MUCH MOISTURE 
EXCEPT W OF 134W AND E OF 98W WHERE SCATTERED MODERATE 
CONVECTION EXIST.   

ELSEWHERE AT THE SURFACE...HIGH PRES CENTER 1020 MB AT 26N130W 
WITH RIDGE SE TO NEAR 18N115W.  EARLIER FRESH TRADES AROUND 
SOUTHERN PERIPHERY OF RIDGE WEAKENED BELOW 20 KT.  RIDGE PROMPTS 
FRESH NW WINDS AND 8 FT SEAS ALONG W COAST OF BAJA CALIFORNIA N 
OF 28N LATE IN FORECAST PERIOD. 

COLD FRONT BRINGS TEMPORARY FRESH BREEZE AHEAD OF BOUNDARY...BUT 
IT BIGGEST IMPACT IS LARGE LONG PERIOD NW SWELLS THAT SPREAD SE 
ACROSS MOST OF BASIN BY END OF FORECAST PERIOD.

FRESH SW MONSOON FLOW INCREASES OVER WATERS FROM 02N TO 08N E OF 
95W...AND SW CROSS-EQUATORIAL SWELLS BUILD SEAS TO 12 FT LATE IN 
FORECAST PERIOD. 

$$
WALLY BARNES