000
AXPZ20 KNHC 170358
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON AUG 17 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...SPECIAL FEATURE...

HURRICANE GUILLERMO CENTERED AT 20.7N 141.4W AT 0300 UTC MOVING 
W NW OR 285 DEGREES AT 13 KT. MAXIMUM SUSTAINED WINDS ARE 65 KT 
WITH GUSTS TO 80 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 985 
MB. NUMEROUS MODERATE TO STRONG CONVECTION IDS NOTED FROM 19N TO 
21N W OF 138W. SEE THE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS HFOTCMCP4/WTPA24 PHFO FOR MORE DETAILS. 

...TROPICAL WAVES...

A TROPICAL WAVE IS LOCATED ALONG 91W N OF 07N...MOVING W AT 
ABOUT 15 KT. THE WAVE REMAINS ON THE ERN SIDE OF AN UPPER LOW 
CENTERED OVER THE WESTERN GULF OF MEXICO NEAR 21N96W THAT 
CONTINUES TO ENHANCE SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION OVER PORTIONS OF NRN CENTRAL AMERICA...THE YUCATAN 
PENINSULA AND SE GULF S OF 23N WITHIN 150 NM OF THE WAVE AXIS.

A TROPICAL WAVE IS LOCATED ALONG 103W FROM 07N TO 16N...MOVING W 
AT ABOUT 15 KT. THIS WAVE IS ALSO WEAK WITH ISOLATED MODERATE
CONVECTION WITHIN TWO TO THREE DEGREES EITHER SIDE OF THE WAVE 
AXIS FROM 10N TO 16N. 

A TROPICAL WAVE IS LOCATED ALONG 119W FROM 06N TO 15N...MOVING W 
10 TO 15 KT AND TRAILING THE WAKE OF DIVERGENT FLOW ALOFT ON THE 
SE SIDE OF AN UPPER CYCLONIC CENTER NEAR 18N12W. THIS IS AIDING 
MODEST CONVECTION ALONG THE ITCZ ON EITHER SIDE OF THE TROPICAL 
WAVE BETWEEN 115W AND 125W.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG THE AXIS 
FROM 08N82W TO 10N120W TO 09N125W TO 12N140W. SCATTERED MODERATE 
CONVECTION WITHIN 150 NM EITHER SIDE OF AXIS BETWEEN 115W AND 
125W. SCATTERED MODERATE WITHIN 120 NM N OF AXIS W OF 135W.

...DISCUSSION...

E OF 11OW...A BROAD UPPER ANTICYCLONE IS CENTERED NEAR 22N108W 
JUST TO THE S OF BAJA PENINSULA. DRY SUBSIDENT FLOW ALOFT TO THE 
EAST...BETWEEN THE UPPER ANTICYCLONE AND AN UPPER LOW OVER THE 
WESTERN GULF OF MEXICO...WILL ENHANCE DRAINAGE FLOW CONVERGENCE 
AND SUBSEQUENT EARLY MORNING COASTAL CONVECTION ALONG THE 
PACIFIC COAST OF CENTRAL MEXICO. FURTHER NORTH...SURFACE HIGH 
PRES OVER THE NW PACIFIC IS MAINTAINING 20 KT NW FLOW ALONG THE 
CENTRAL BAJA COAST AS NOTED BY SHIP OBSERVATIONS FEW HOURS AGO. 
INCREASED S TO SW FLOW TO THE SOUTH OF THE ITCZ WILL BRING A 
SLIGHT INCREASE IN CONVECTION ALONG THE ITCZ MAINLY N OF THE 
GALAPAGOS ON MONDAY.

W OF 110W...THE CENTER OF HURRICANE GUILLERMO IS NOW WEST OF 
140W AND WEST OF THE DISCUSSION AREA...BUT WINDS OF TROPICAL 
STORM FORCE OR GREATER WILL PERSIST OVER THE NEXT SEVERAL HOURS 
E OF 140W. IN ADDITION...A TIGHT GRADIENT BETWEEN GUILLERMO AND 
HIGH PRES N OF THE AREA WILL MAINTAIN A BROAD SWATH OF 20 TO 33 
KT WINDS AND SEAS TO 12 FT THROUGH EARLY MONDAY...WITH GRADUAL 
DIMINSHING WINDS AND SEAS THROUGH TUE. 

$$
CHRISTENSEN