000
AXPZ20 KNHC 200952
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED OCT 20 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...
AXIS ALONG 09N84W TO 08N90W TO 08N100W TO 06N112W TO 09N126W TO 
09N140W.  SCATTERED MODERATE CONVECTION WITHIN 60 NM OF AXIS FROM
127W TO129W.

...DISCUSSION...
WELL-DEFINED MID/UPPER LEVEL CYCLONE OVER CALIFORNIA/BAJA 
CALIFORNIA BORDER DRIFT SE WITH TROUGH S-SW TO 22N126W AND 
SHOULD MOVE FURTHER INLAND TODAY.  WEAKENING 90-95 KT JET CORE 
HAS DIVERGENT FLOW ALOFT OVER SURFACE TROUGH PRESENTLY AT THE 
TIP OF SOUTHERN NEVADA PROMPTING NUMEROUS SHOWERS AND SCATTERED 
TSTMS OVER NORTHERN BAJA CALIFORNIA.  WEATHER SHOULD CONTINUE 
THROUGH TODAY THEN ABATE THU AS SYSTEM MOVES NE.

BROAD RIDGE CRESTING ACROSS WESTERN PART OF BASIN BRINGS ITCZ 
CONVECTIVE DEBRIS MOISTURE INTO E PAC...MAINLY N OF 10N W OF 
120W...BUT STILL FAR AWAY FROM ANY FEATURE CAPABLE OF CAUSING 
SIGNIFICANT WEATHER WITH IT.  ELSEWHERE ACROSS BASIN...LARGE 
AREA OF MODERATE TO STRONG SUBSIDENCE MAINTAINS DRY STABLE AIR 
MASS EASTWARD TO 90W INHIBITING ITCZ FROM MOST ACTIVITY.  
 
CARIBBEAN UPPER LEVEL ANTICYCLONE PUMPS ABUNDANT TROPICAL 
MOISTURE INTO E PAC MAINLY E OF 85W...BUT MIGHT TAKE SOME TIME 
FOR MONSOONAL TROUGH TO EXPAND EASTWARD TO CATCH UP WITH IT.  BY 
LATE IN THE FORECAST PERIOD CONVECTION IS LIKELY TO DEVELOP AS 
THESE TWO FEATURES MERGE.   

ELSEWHERE AT THE SURFACE...
COLD FRONT APPROACHES NW CORNER OF BASIN BRINGING STRONG SW 
WINDS AHEAD OF IT BUT BARELY MODERATE BREEZE BEHIND.  POSSIBLY 
MORE SIGNIFICANT WOULD BE BUILD UP OF NW SWELL TRAIN FOLLOWING 
FRONT.  FRONT WEAKENS AND DISSIPATES BY END OF PERIOD BUT 12-15 
FT SWELLS LINGER AND SPREAD SE.  

HIGH PRES CENTER 1021 MB AT 28N134W HAS RIDGE EXTEND TO 12N110W. 
MODERATE BREEZE ALONG ITS SOUTHERN PERIPHERY WEAKEN AS RIDGE IS 
FORCED S BY APPROACHING COLD FRONT. 

FRESH SW WINDS EXTEND OVER E PORTION OF BASIN WITHIN 36-48 HRS 
AS MONSOONAL TROUGH TRAPS ENERGY FROM MOIST TROPICAL FLOW 
SUPPORTED BY LOW PRES...POSSIBLE TROPICAL CYCLONE OVER WESTERN 
CARIBBEAN.

$$
WALLY BARNES