000
AXPZ20 KNHC 300931
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT AUG 30 2008

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 
0845 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 105W S OF 18N MOVING W 10 KT. THE WAVE IS 
EMBEDDED WITHIN STRONG LOW-LEVEL WESTERLY FLOW DUE TO THE 
MONSOON TROUGH...AND THUS HAS MADE VERY SLOW WESTWARD PROGRESS. 
MODEL GUIDANCE IS SUGGESTING THAT AN AREA OF LOW PRES COULD FORM 
ALONG THIS WAVE WITHIN THE NEXT 24 HOURS...BUT THE LOW WOULD 
LIKELY RETROGRADE EASTWARD AS THE WAVE CONTINUES TO THE W. 
SCATTERED SHOWERS/TSTMS ARE CURRENTLY WITHIN 120 NM OF THE WAVE 
AXIS.
     
...ITCZ...

ITCZ AXIS IS CENTERED FROM 08N77W TO 08N90W TO 09N100W TO 
10N120W TO 07N140W. SCATTERED MODERATE FROM 05N TO 10N BETWEEN 
84W AND 88W. SCATTERED MODERATE WITHIN 120 NM OF AXIS BETWEEN 
102W AND 120W.

...DISCUSSION...

TROPICS...
THE AXIS OF THE MONSOON TROUGH IS NEAR 17N E OF 112W WITH 
MODERATE LOW-LEVEL SOUTH/SOUTHWESTERLIES EXTENDING FROM THE 
EQUATOR TO THE AXIS. THIS TYPE OF PATTERN MAKES TRACKING 
EMBEDDED EASTERLY WAVES DIFFICULT. DISORGANIZED SHOWER/TSTM 
ACTIVITY IS MAINLY S OF THE MONSOON TROUGH WHERE THE LOW-LEVEL 
CONVERGENCE IS STRONGEST. THE UPPER LEVEL FLOW OVER THE REGION 
IS PRIMARILY NE/EASTERLY... WHICH IS PROVIDING GOOD DIFFLUENCE 
OVER THE AREA. MODEL GUIDANCE IS SUGGESTING THAT AN AREA OF LOW 
PRES COULD DEVELOP FROM THIS TROUGH...AS MENTIONED ABOVE...WITH 
A STRENGTHENING OF THE LOW-LEVEL SOUTHWESTERLIES WITHIN THE NEXT 
24-48 HOURS. W OF 112W...THE NORMAL ITCZ CONFIGURATION IS IN 
PLACE WITH UPPER LEVEL EASTERLIES DOMINATING THE REGION.

SUBTROPICS...
A 1032 MB HIGH IS N OF THE AREA NEAR 44N150W. THUS THE SURFACE 
RIDGE S OF 30N IS WEAK AT THE MOMENT WITH WINDS GENERALLY 5-10 
KT ACROSS THE AREA. A COLD FRONT IS ALSO N OF THE AREA ALONG 36N 
BETWEEN 130W TO 140W. IN THE UPPER LEVELS...A STRONG UPPER LEVEL 
HIGH IS CENTERED W OF THE BAJA PENINSULA NEAR 22N120W. A SMALL 
UPPER LOW OVER EXTREME NW MEXICO NEAR 28N110W. EXPECT...AN AREA 
OF STRONG NLY WINDS OFF THE CALIFORNIA COAST TO EXPAND SWD OVER 
THE NEXT 48 HRS...POSSIBLY INCREASING TO 25 KT S OF 30N...AND 
RESULT IN 8-12 FT NLY SWELLS MOVING S INTO THE REGION.

$$
FORMOSA