000
AXPZ20 KNHC 041520
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE SEP 04 2012

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURE...
TROPICAL DEPRESSION JOHN AT 23.5N 116.5W 1005 MB AT 1500 UTC 
MOVING NW OR 315 DEG AT 12 KT ALONG SW PERIPHERY OF MID TO UPPER 
LEVEL RIDGE. DEEP CONVECTION HAS DIMINISHED WITH NO SIGNIFICANT 
CONVECTIVE ACTIVITY WITH THE SYSTEM. MAXIMUM SUSTAINED WINDS 30 
GUSTS TO 40 KT OVER N SEMICIRCLE. JOHN REMAINS UNDER MODERATE NE 
WIND SHEAR ALOFT AND MOVING OVER MUCH COOLER SURFACE WATERS. IT 
IS EXPECTED TO FURTHER WEAKEN OVER NEXT FEW DAYS INTO A REMNANT 
LOW PRES. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 14N91W TO 08N100W TO 12N115W TO 11N127W THEN 
ITCZ TO 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
FROM 5N-11N BETWEEN 110W-120W.

...DISCUSSION...
COMPLEX DUAL UPPER LEVEL CYCLONES N OF AREA WITH TROUGH EXTENDS 
INTO THE DISCUSSION AREA FROM 32N132W TO 26N134W TO 23N140W. 
VERY DRY AIR MASS DUE WITH MODERATE TO STRONG SUBSIDENCE COVERS 
THE AREA W OF 125W...EFFECTIVELY ABSORBING ALL CONVECTION FROM 
REMNANTS OF ILEANA NOW NEAR 20N130W. WELL DEFINED ANTICYCLONE 
ALOFT W OF THE BAJA PENINSULA NEAR 27N118W. INVERTED UPPER LEVEL 
TROUGH EXTENDS FROM CENTRAL MEXICO TO 05N106W. ABUNDANT TROPICAL 
MOISTURE IS ALONG AND E OF THE TROUGH.

ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRES RIDGE WITH AXIS 
FROM 31N138W TO 22N123W.

$$
DGS