000
AXPZ20 KNHC 301608
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT AUG 30 2008

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 
1445 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 106W FROM 10N-17N MOVING W 10 KT HAS 
MODERATE TO STRONG SHEAR ALOFT N OF ITCZ INHIBITING ITS 
DEVELOPMENT.  WAVE TRAVELING ALONG SRN PERIPHERY OF BROAD UPPER 
LEVEL ANTICYCLONE CENTERED AT 22N118W.  THESE CONDITIONS LIKELY 
EXTENDING TO 130W LIMITING CHANCES OF CYCLONIC ORGANIZATION OF 
WAVE.  SCATTERED MODERATE CONVECTION IS SEPARATING FROM WAVE 
AXIS.
     
...ITCZ...
ITCZ AXIS ALONG 09N78W TO 12N100W TO 12N120W TO 08N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 150 NM OF 
LINE 05N79W TO 07N88W AND WITHIN 240 NM OF LINE 16N102W TO 
07N119W.

...DISCUSSION...
LARGE AMPLITUDE TROUGH ENTER E PAC AT 140W EXPECTED TO SHIFT NE 
AS BROAD ANTICYCLONE AT 22N118W WILL BLOCK ANY FURTHER EWD 
INTRUSION.  AIR MASS REMAINS VERY DRY N OF 17N W OF 109W DUE TO 
MODERATE TO STRONG SUBSIDENCE UNDER ANTICYCLONE.

PLENTY OF TROPICAL MOISTURE ADVECTING ALONG SRN FRINGES OF 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...
HIGH PRES 1032 MB NW OF AREA AT 44N150W WITH WEAK SURFACE RIDGE 
S OF 30N HAS LIGHT WINDS ACROSS FORECAST AREA.  COLD FRONT N OF 
AREA ALONG 36N FROM 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.

$$
WALLY BARNES