000
AXPZ20 KNHC 022137
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE SEP 02 2008

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.

...SPECIAL FEATURE...
TROPICAL STORM KARINA 1000 MB AT 19.5N 112.3W AT 2100 UTC MOVING 
W-NW AT 9 KNOTS.  SCATTERED TO NUMEROUS STRONG DEEP CONVECTION 
CONFINED TO WITHIN 180 NM OF CENTER IN W SEMICIRCLE AS ELY WIND 
SHEAR CURTAILS ITS CHANCES OF SIGNIFICANT FURTHER DEVELOPMENT.  
COOL SEA SURFACE TEMPERATURES AND CONTINUOUS SHEAR EXPECTED TO 
CURTAIL FURTHER DEVELOPMENT KEEPING KARINA AS MINIMAL TROPICAL 
STORM AND SHOULD WEAKEN AFTER 24 HRS.

...ITCZ...
ITCZ AXIS ALONG 10N84W TO 11N108W TO 09N120W TO 07N140W.  
SCATTERED MODERATE WITHIN 120 NM S OF AXIS FROM 87W-137W.

...DISCUSSION...
COMPLEX MID-UPPER LEVEL RIDGE WITH TWO ANTICYCLONIC 
CENTERS...ONE AT 25N112W AND SECOND ONE AT 26N105W...EXTEND W 
ALONG 23N-24N TO 20N137W. VERY DRY AIR MASS UNDER RIDGE UMBRELLA 
N OF 23N AND N OF 091N W OF 120W DUE TO MODERATE TO STRONG 
SUBSIDENCE CURTAILING MOST SIGNIFICANT DEEP CONVECTION FROM 
DEVELOPING...ALBEIT TROPICAL STORM KARINA SITTING AT THE EDGE 
WITH LARGE SWATH OF MOIST AIR.  MAIN TROPICAL MOISTURE SWATH S 
OF ITCZ AND ASSOCIATED WITH MONSOONAL TROUGH N OF 15N E OF 108W.

LARGE AMPLITUDE LONGWAVE TROUGH AXIS FROM 32N132W TO 17N140W 
EXTEND DRY SLOT TO WRN FRINGES OF FORECAST REGION.  TROUGH 
UNABLE TO ADVANCE FURTHER E DUE TO ANTICYCLONE BLOCK WILL SHIFT 
NE AND MOVE N OF AREA WITHIN 48 HRS.  

ELSEWHERE AT THE SURFACE...
HIGH PRES CENTER 1030 MB AT 38N142W HAS RIDGE COVERING AREA N OF 
23N116W WITH KARINA RIGHT AT ITS EDGE.  LOW PRES TROUGH OVER 
COAST OF NRN CALIFORNIA PRODUCING N GALE FORCE WINDS N OF 
FORECAST AREA WHICH SPILL INTO E PAC S OF 32N WITH 20-25 KT 
WINDS AND 9 FT OVER N AND NW PORTIONS OF AREA.  THESE CONDITIONS 
FORECAST TO SLOWLY SUBSIDE OVER NEXT 48 HOURS.

SW WIND FIELD S OF MONSOON TROUGH COMBINED WITH CROSS EQUATORIAL 
SWELLS CAUSING 10 FT SEAS S OF ITCZ FROM 91W-122W.  CONDITIONS 
LIKELY LAST THROUGH THROUGH FORECAST PERIOD BEFORE SUBSIDING.  

$$
WALLY BARNES