000
AXPZ20 KNHC 151001
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT AUG 15 2009

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 
0945 UTC.

...SPECIAL FEATURES...

HURRICANE GUILLERMO CENTERED AT 18.7N 131.9W AT 0900 UTC...OR 
ABOUT 1450 NM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA...MOVING 
WNW OR 285 DEG AT 14 KT. MAXIMUM SUSTAINED WINDS ARE 100 KT WITH 
GUSTS TO 120 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS ESTIMATED 
AT 960 MB. GUILLERMO RAPIDLY INTENSIFIED OVER THE PAST FEW 
HOURS WITH 20 NM EYE. CURRENTLY NUMEROUS STRONG CONVECTION IS 
OBSERVED WITHIN 90 NM OVER THE SW SEMICIRCLE AND WITHIN ABOUT 30 
NM OVER THE NE SEMICIRCLE OF HURRICANE CENTER. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IN BANDS IS NOTED ELSEWHERE 
WITHIN 150 NM OF CENTER. GUILLERMO IS EXPECTED TO REMAIN A 
MINIMAL HURRICANE TODAY THEN BEGIN TO WEAKEN BACK TO A TROPICAL 
STORM AS HE MOVES OVER COOLER WATERS...DRY AIR ENTRAINMENT AND 
WIND SHEAR. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. 

THE BROAD REMNANT LOW PRES OF TROPICAL DEPRESSION NINE-E IS 
QUASI STATIONARY NEAR 11N139W AND IS ESTIMATED AT 1008 MB.  
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS OBSERVED 
WITHIN 60 NM NE AND WITHIN 120 NM SW SEMICIRCLES OF CENTER.

...TROPICAL WAVES...

A TROPICAL WAVE IS ANALYZED N OF 05N ALONG 81W WITH WESTWARD 
MOTION ESTIMATED AT 20 KT THROUGH THE WESTERN CARIBBEAN. 
SCATTERED MODERATE CONVECTION IS MOVING OFF THE COAST OF 
COLOMBIA TO THE E OF THE WAVE AXIS.

A TROPICAL WAVE IS ANALYZED FROM 04N TO 16N ALONG 94W AND HAS 
BEEN MOVING W AT 20 KT OVER THE PAST 48 HOURS. SCATTERED 
MODERATE TO STRONG CONVECTION IS MOVING THROUGH THE GULF OF 
TEHUANTEPEC AT THE MOMENT.

A TROPICAL WAVE IS ANALYZED FROM 04N TO 16N ALONG 108W AND HAS 
BEEN MOVING W AT 18 TO 20 KT OVER THE PAST 48 HOURS. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS FLARING WITH 120 NM OF 
THE WAVE AXIS FROM 07N TO 15N.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 09N83 TO 
12N109W TO 10N116W TO 15N127W TO 11N140W. SCATTERED MODERATE AND 
ISOLATED STRONG CONVECTION IS NOTED WITHIN 180 NM EITHER SIDE OF 
LINE FROM 05N86W TO 12N104W TO 11N140W.

...DISCUSSION...

ANTICYCLONIC FLOW ASSOCIATED WITH AN UPPER ANTICYCLONE AT 
23N127W IS DOMINATING MOST OF THE UPPER LEVELS W OF 120W WITH AN 
UPPER TROUGH JUST NW OF THE AREA. UPPER DIFFLUENCE CONTINUES TO 
SUPPORT OUTFLOW OVER HURRICANE GUILLERMO AND OVER THE ITCZ 
BETWEEN 120W AND 140W. THE RESULTANT DEBRIS MOISTURE HAS SPREAD 
N TO ALONG 27N BETWEEN 125W AND 133W AND IS ALSO ADVECTED S TO 
THE EQUATOR BETWEEN 125W AND 135W. DRY UPPER AIR IS NOTED N OF 
15N W OF 135W MERGING WITH THE UPPER DRY AIR DOMINATING THE 
UPPER LEVELS TO THE N OF 27N W OF 112W. HURRICANE GUILLERMO MAY 
BEGIN TO ENTRAIN SOME OF THIS DRY AIR WITHIN THE 24 HOURS AS HE 
ALSO TRACKS OVER COOLER SURFACE WATER.     

A SECOND UPPER ANTICYCLONE IS OVER CENTRAL AMERICA AT 19N97W AND 
DOMINATES THE UPPER LEVELS OF DEEP TROPICAL PACIFIC BETWEEN 90W 
AND 105W. THE ASSOCIATED UPPER DIFFLUENCE HAS BEEN ENHANCING 
CONVECTION ALONG THE ITCZ BETWEEN 90W AND 110W. AN UPPER LEVEL 
CYCLONE HAS MOVED W OVER THE PACIFIC NEAR 21N111W WITH A TROUGH 
EXTENDING S ALONG 10N113W THEN CONTINUING S ACROSS THE EQUATOR 
AT 113W. AN UPPER CYCLONE OVER THE CARIBBEAN NEAR 19N82W HAS A 
TROUGH EXTENDING SW ACROSS HONDURAS TO NEAR 10N91W. A BROAD 
RIDGE THAT ORIGINATES OVER S AMERICA IS NOTED OVER THE 
DISCUSSION AREA E OF 90W.  

AT LOW LEVELS A SURFACE RIDGE EXTENDS INTO THE AREA AT 32N132W 
TO 12N117W.

GAP WINDS...THE LATEST ASCAT PASS INDICATES THAT NNW WINDS 
OF 15 TO 20 KT ARE STILL SURGING THROUGH THE GULF OF 
TEHUANTEPEC. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH 
LATE MORNING TODAY THEN DIMINISH. LATEST QSCAT AND SSMI PASSES 
SUGGEST NE WINDS AT 15 TO 20 KT ARE SURGING INTO THE GULF OF 
PAPAGAYO AND MAY OCCASIONALLY INCREASE TO 20 TO 25 KT OVER THE 
NEXT COUPLE OF DAYS AS EASTERLY TRADES ARE FAIRLY STRONG 
UPSTREAM IN W CARIBBEAN. 

$$
NELSON