000
AXPZ20 KNHC 171551
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON AUG 17 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...
TROPICAL STORM GUILLERMO CENTER W OF AREA AT 21.5N 144.5W AT 
1500 UTC MOVING W-NW OR 290 DEG AT 16 KT.  MAXIMUM SUSTAINED 
WIND 50 WITH GUSTS TO 60 KT.  SCATTERED MODERATE CONVECTION FROM 
17N TO 22N W OF 139W.  SEE LATEST FORECAST/ADVISORY UNDER AWIPS/ 
WMO HEADERS HFOTCMCP4/WTPA24 PHFO FOR MORE DETAILS. 

...TROPICAL WAVES...
TROPICAL WAVE N OF 08N ALONG 94W MOVE W AT 15 KT IS APPROACHING 
HOSTILE ENVIRONMENT ALOFT WHICH IS EXPECTED TO CURTAIL ANY 
CHANCE OF INTENSIFICATION.  ASSOCIATED SCATTERED MODERATE 
CONVECTION...MAINLY ALONG INTERSECTION WITH ITCZ...QUICKLY 
DIMINISHING. 

TROPICAL WAVE FROM 07N-16N ALONG 107W MOVE W AT 15 KT STILL 
UNDER ADVERSE UPPER LEVEL ENVIRONMENT AT LESSER DEGREE...BUT IS 
NOT EXPECTED TO BE UNDER FAVORABLE CONDITIONS FOR NEXT 48 HRS.  
ISOLATED MODERATE CONVECTION JUST W OF AXIS ALONG ITCZ.  

TROPICAL WAVE FROM 07N-15N ALONG 122W MOVE W AT 15 KT IS 
ENTERING AREA OF VERY FAVORABLE CONDITIONS WHERE UPPER LEVEL 
CYCLONE INDUCES STRONG DIFFLUENCE ALOFT ENHANCING SCATTERED 
MODERATE ISOLATED STRONG CONVECTION.  GLOBAL MODEL SOLUTIONS 
GIVE BETTER SHORT LIVED CYCLONIC ORGANIZATION TO WAVE DURING 
NEXT 48 HRS.

...ITCZ...
AXIS ALONG 08N78W TO 10N105W TO 12N119W TO 10N132W TO 10N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM N AND 
240 NM S OF AXIS E OF 86W.  ALL OTHER CONVECTION ALONG ITCZ IS 
ASSOCIATED WITH TROPICAL WAVES.

...DISCUSSION...
UPPER LEVEL ANTICYCLONE AT 25N132W HAS RIDGE EXTEND SW TO 
22N140W.  DEBRIS MOISTURE FROM TROPICAL STORM GUILLERMO OUTFLOW 
ADVECTED NE ACROSS NW CORNER OF E PAC.  WELL DEFINED CYCLONIC 
VORTEX AT 20N123W HAS WEAK TROUGH EXTENDING S TO N FRINGES OF 
TROPICAL WAVE ALONG 122W INDUCING MODERATE TO STRONG DIFFLUENCE 
ALOFT WHICH ENHANCES SCATTERED CONVECTION ALONG N HALF OF WAVE.

BROAD SECOND UPPER LEVEL ANTICYCLONE OVER NW MEXICO AT 26N107W 
HAS RIDGE EXTEND S INTO TROPICAL E PAC BETWEEN 103W-118W.  
MODERATE NE SHEAR CURTAILS CONVECTION ALONG TROPICAL WAVE ALONG 
107W N OF ITCZ.   DOWNSTREAM UPPER LEVEL CYCLONE OVER BAY OF 
CAMPECHE AT 19N98W WITH TROUGH S ACROSS ISTHMUS AND GULF OF 
TEHUANTEPEC TO 10N100W CREATING ADVERSE ENVIRONMENT TO TROPICAL 
WAVE ALONG 94W.   

ELSEWHERE AT THE SURFACE...
HIGH PRES CENTER N OF BASIN HAS RIDGE EXTEND SE TO 17N115W 
SQUEEZES GRADIENT ALONG BAJA CALIFORNIA COAST FORCING MODERATE 
TO FRESH NW BREEZE.  RIDGE WEAKENS AND BREEZE DIMINISH WITHIN 36 
HRS.  

CROSS EQUATORIAL FRESH BREEZE AND 8 FT SWELLS AFFECTING AREA S 
OF 08N E OF 100W EXPECTED TO DECREASE IN COVERAGE WITHIN NEXT  
48 HRS.    

$$
WALLY BARNES