000
AXPZ20 KNHC 130342
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN AUG 13 2006

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 
0215 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 108W FROM 3N TO 16N MOVING W 15 KT HAS HAS 
LIGHT EASTERLY SHEAR ALOFT NOR ADVERSE TO DEVELOPMENT BUT IS 
TRAPPED BETWEEN TWO DRY AREAS N AND S.  ONLY CONVECTION OBSERVED 
IS ALONG ITCZ BETWEEN 10N AND 12N.  CONVECTION COULD PULSATE 
BETWEEN BURSTS OF TSTMS DUE TO FAVORABLE WINDS ALOFT THEN 
DECREASE DUE TO DRY AIR ENTRAINMENT.  

TROPICAL WAVE ALONG 80W HAS VERY UNFAVORABLE STRONG SE SHEAR 
THAT HAS WIPED OUT MOST SIGNIFICANT CONVECTION.  ALTHOUGH PLENTY 
OF MOISTURE IS AVAILABLE HOSTILE UPPER ENVIRON MAKES DEVELOPMENT 
HARD TO COME BY NEXT 48 HRS. 

...ITCZ...
ITCZ AXIS CENTERED ALONG 11N86W  10N98W  11N108W  8N126W  
12N140W. SCATTERED TSTMS WITHIN 60 NM OF AXIS E OF 110W.  
SCATTERED MODERATE FROM 12N TO 18N W OF 137W ASSOCIATED TO 
TROPICAL WAVE W OF 140W.  SCATTERED MODERATE TO STRONG 
ASSOCIATED WITH SURFACE TROUGH FROM 10N TO 15N BETWEEN 98W AND 
102W.

...DISCUSSION...
SHARP UPPER LEVEL RIDGE W OF OF 130W BRINGS DRY AIR MASS TO E 
PAC BASIN RIGHT BEHIND UPPER LEVEL TROUGH AXIS FROM 32N119W TO 
17N127W.  STUBBORN STATIONARY MID/UPPER LEVEL RIDGE HOLDS IN 
PLACE OVER SW CONUS IN SPITE OF PUSH BY UPPER TROUGH.  TROUGH 
ADVECTING TROPICAL MOISTURE FROM ITCZ NORTHEASTWARD BUT DRY AIR  
MASS UNDER RIDGE PREVENTS IT FROM REACHING BAJA CALIFORNIA.  

DOWNSTREAM...UPPER LEVEL CYCLONIC VORTEX OVER MEXICO FORECAST TO 
DEEPEN IN PLACE AS RIDGE WILL NOT ALLOW NORTHWARD ENCROACHMENT. 
THIS WILL PROVIDE GOOD UPPER DIFFLUENCE OVER NW MEXICO. MOISTURE 
ADVECTING FROM ITCZ MENTIONED ABOVE SHOULD NOT BE AVAILABLE TO 
ENHANCE CONVECTION IN AREA...OTHERWISE WE COULD SEE PLENTY OF 
PRECIPITATION OVER AREA.  

AT THE SURFACE...
STRONG ANTICYCLONIC CIRCULATION WELL NW OF AREA HAS RIDGE EXTEND 
SE TO 17N108W WITH STRONG N-NW WINDS ALONG CALIFORNIA COAST 
PRODUCING MODERATE SWELLS FURTHER S.  GFS WEAKENS RIDGE AND BRING
WINDS DOWN WITHIN 24 HRS...BUT BRING IT BACK AGAIN IN 72 HRS. 
FORECAST WILL FOLLOW IT...FOR THE TIME BEING.  ALSO TRADES 
CONTINUE ON SCHEDULE WITH STRONG NE WINDS W OF 130W DIMINISHING 
WITHIN 24 HRS.

FARTHER E...STRONG CARIBBEAN TRADES FORCED BY STRONG ATLC RIDGE 
SPILLING INTO E PAC ACROSS GULF OF PAPAGAYO...ENHANCED BY 
TROPICAL WAVE ALONG 79W...TO CONTINUE NEXT 48 HRS.

$$
WALLY BARNES