000
AXPZ20 KNHC 011026
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT SEP 01 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0915 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ILEANA AT 22.7N 117.9W AT 01/0900 UTC MOVING W AT 
8 KT WITH MINIMUM CENTRAL PRESSURE OF 998 MB.  MAXIMUM SUSTAINED 
WIND SPEED 45 GUSTS TO 55 KT.  SCATTERED MODERATE ISOLATED 
STRONG CONVECTION REMAINS CONCENTRIC WITHIN 90 NM SW AND W OF 
CENTER.  ILEANA MOVING OVER INCREASINGLY COOLER SEA SURFACE 
TEMPERATURES AND STABLE AIR AND EXPECTED TO WEAKEN.  SEE LATEST 
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 
KNHC FOR MORE DETAILS.

TROPICAL LOW...BROAD CYCLONIC SWIRL WITHIN MONSOON TROUGH AT 
12N101W SEEMS DISORGANIZED AS SCATTERED CONVECTION REMAINS 
SEPARATED FROM CENTER.  MODEL GUIDANCE SOLUTIONS INDICATE LOW 
PRES WILL MOVE W THEN TURN NW AND DEEPEN TO POSSIBLE TROPICAL 
CYCLONE...BUT TIME REMAINS SHORT BEFORE WATER TEMPERATURES TAKE 
THEIR TOLL AND CONTINUOUS EASTERLY WIND SHEAR ALOFT INCREASE. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH FROM FROM 08N78W TO 15N96W TO 1009 MB LOW PRES AT 
12N101W...THEN RESUMES FROM 15N116W TO 10N130W THEN ITCZ TO 
BEYOND 11N140W.  SCATTERED MODERATE ISOLATED STRONG CONVECTION 
WITHIN 90 NM OF AXIS FROM 94W TO 104W AND ELSEWHERE FROM 08N TO 
15N BETWEEN 108W AND 110W.

...DISCUSSION...

UPPER LEVEL LONG WAVE TROUGH COMBINES WITH WEAK ANTICYCLONE AT 
16N134W TO MAINTAIN DRY CONDITION DUE TO MODERATE SUBSIDENCE W 
OF 120W...SPELLING DOOM FOR APPROACHING T.S. ILEANA...PRESENTLY 
NEAR 118W.  UPPER LEVEL RIDGE EXTENDING FROM GULF OF MEXICO INTO 
E PAC BRINGS ABUNDANT TROPICAL MOISTURE INTO LARGE PORTIONS OF 
BASIN MAINLY E OF 120W.  DEBRIS MOISTURE FROM ILEANA STEERS N-NE 
IN PLUME ON WESTERN PERIPHERY OF RIDGE. 

ELSEWHERE AT THE LOW LEVELS...BROAD LOW PRES CENTER AT 12N101W 
REMAINS UNDER STEADY E WIND SHEAR BUT MAINTAIN MEDIUM CHANCE OF 
DEVELOPING INTO A TROPICAL SYSTEM.   

FRESH SW MONSOONAL FLOW WITH SEAS 8-10 FT NOTED S OF MONSOONAL 
TROUGH ENHANCING CROSS EQUATORIAL SOUTHERLY SWELLS SPREADING 
INTO BASIN S OF 17N.

$$
WALLY BARNES