000
AXPZ20 KNHC 062202
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE OCT 06 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...TROPICAL WAVE... 

A TROPICAL WAVE WAS ANALYZED ALONG 91W N OF 08N. THE WAVE IS 
WITHIN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN TOTAL 
PRECIPITABLE WATER IMAGERY. THIS FEATURE MAY INTERACT WITH 
MORNING DRAINAGE FLOW TO ENHANCE AREAS OF SHOWERS AND TSTMS 
ALONG THE COASTS OF GUATEMALA AND MEXICO. WINDS TO 20 KT ARE 
FORECAST TO DEVELOP IN RELATION TO THIS WAVE AS WELL ON THE EAST 
SIDE OF THE WAVE.

...ITCZ...

THE ITCZ AXIS WAS ALONG 09N79W TO 11N90W TO 10N101W TO 11N110W 
TO 07N130W TO 10N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 
120 NM S OF THE AXIS BETWEEN 93W AND 98W. SCATTERED MODERATE 
WITHIN 120 NM S OF THE AXIS BETWEEN 91W AND 93W.

...DISCUSSION...
AN UPPER LEVEL RIDGE EXTENDS FROM CENTRAL MEXICO THROUGH 13N135W 
CONTINUES TO SHIFT EAST AND WEAKEN...AHEAD OF A MID TO UPPER 
LEVEL TROUGH EXTENDING FROM CENTRAL CALIFORNIA TO 30N130W TO 
18N130W. A QUIKSCAT PASS FROM 1430Z SHOWED EVIDENCE OF A WEAK 
SURFACE TROUGH ASSOCIATED WITH THE MID TO UPPER LEVEL 
TROUGH...EXTENDING FROM 28N130W TO 24N130W WITH NE WINDS TO 20 
KT MAINLY W OF THE TROUGH. THIS APPEARS TO BE DAMPENING OUT 
HOWEVER...ALLOWING THE WINDS TO DIMINISH LATER TODAY. 

SHIP AND SCATTEROMETER DATA INDICATE GENERALLY 15 KT NW FLOW 
ALONG THE BAJA COAST...ON THE EASTERN PERIPHERY OF THE 
RIDGE...WITH SOME EVIDENCE THAT WINDS ARE STARTING TO INCREASE 
TO 20 KT AS THE RIDGE BUILDS IN FROM THE WEST. 

FURTHER SOUTH...A 1010 MB LOW IS NOTED ALONG THE MAIN ITCZ NEAR 
112W. THIS FEATURE WILL DRIFT SLOWLY WNW OVER THE NEXT COUPLE OF 
DAYS...AND ALTHOUGH WILL NOT DEVELOP SIGNIFICANTLY IT MAY 
ENHANCE TRADE WIND FLOW AS IT INTERACTS WITH THE RIDGE TO THE 
NORTH. MEANWHILE...LONG PERIOD SWELL WITH SEAS TO 8 FT COVERS 
THE AREA MAINLY N OF 10N W OF 110W...BUT WAVEWATCH AND FNMOC 
WAVE MODELS SHOW THIS SWELL DECAYING THROUGH TODAY.

EAST OF 110W...MORNING DRAINAGE FLOW CONVECTION HAS BEEN ACTIVE 
FROM EL SALVADOR TO SOUTHERN MEXICO. SOME OF THIS CONVECTION CAN 
BE ATTRIBUTED TO THE TROPICAL WAVE ALONG 88W. FURTHER 
NORTH...WINDS OVER THE NORTHERN GULF OF CALIFORNIA HAVE 
DIMINISHED AS A TROUGH OVER THE SOUTHWEST U.S. HAS LIFTED OUT TO 
THE NE. 

$$
CHRISTENSEN