000
AXPZ20 KNHC 122201
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT AUG 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 107W FROM 3N TO 16N MOVING W 15 KT HAS HAS 
LIGHT WINDS ALOFT TO ENHANCE 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 ENTERING E PAC BASIN ALONG 79W HAS VERY 
UNFAVORABLE STRONG SE SHEAR DECREASING LITTLE CONVECTION THERE 
WAS IS LIKELY CONTINUE FOR NEXT 48 HRS ALTHOUGH PLENTY OF 
MOISTURE IS AVAILABLE. 

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N85W  10N113W  9N130W  12N140W. 
SCATTERED TSTMS WITHIN 60 NM OF AXIS E OF 112W.  SCATTERED 
MODERATE FROM 10N TO 16N W OF 137W ASSOCIATED TO TROPICAL WAVE W 
OF 140W.  SCATTERED MODERATE TO STRONG ASSOCIATED WITH SURFACE 
TROUGH FROM 10N-16N BETWEEN 96W-99W.

...DISCUSSION...
SUBTROPICS...
SHARP UPPER LEVEL RIDGE W OF OF 130W BRINGS DRY AIR MASS TO E 
PAC BASIN RIGHT BEHIND UPPER LEVEL TROUGH AXIS FROM 32N121W TO 
17N128W.  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 SHOULD PREVENT 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 18N110W WITH STRONG N-NW WINDS ALONG CALIFORNIA COAST 
PRODUCING MODERATE SWELLS FURTHER S.  GFS WEAKENS RIDGE AND BRING
WINDS DOWN WITHIN 48 HRS...WHICH MIGHT BE JUMPING THE GUN TOO 
FAST...BUT FORECAST LIKELY WILL FOLLOW IT FOR THE TIME BEING.  
ALSO TRADES CONTINUE ON SCHEDULE WITH STRONG NE WINDS N OF 130W.

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