000
AXPZ20 KNHC 030246
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC SAT AUG 03 2013

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...SPECIAL FEATURES...                             
TROPICAL STORM GIL...DOWNGRADED FROM HURRICANE EARLIER TODAY...
NOW AT 14.7N 129.4W AT 03/0300 UTC MOVE W OR 275 DEG AT 10 KT.
ESTIMATED CENTRAL PRES 995 MB.  MAXIMUM SUSTAINED WIND 55 GUSTS
TO 65 KT.  GIL CONVECTION BREAKING DOWN QUICKLY AND IS NOW ONLY 
WITHIN 75 NM N QUADRANT...60 NM S SEMICIRCLE AND WITHIN 30 NM
ELSEWHERE.  ITS PREVIOUS EYEWALL HAS NOW OPENED WIDELY IN THE W
AND MID LEVEL CLOUDS ARE SEEN PULLING AWAY FROM THE CENTER. 
FORECAST CALLS FOR CONTINUED WEAKENING AS GIL MOVES INTO 
PROGRESSIVELY INCREASING SHEAR AND COOLER WATERS. SEE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTNT22 KNHC
FOR ADDITIONAL DETAILS.

JUST E OF GIL...LOW PRES AT 13N120W 1010 MB CENTER HAS BECOME 
EXPOSED FROM CLOUD COVER AND HAS DIMINISHED SIGNIFICANTLY AMOUNT
OF CONVECTION SURROUNDING IT. ENVIRONMENTAL CONDITIONS REMAIN
MARGINALLY CONDUCIVE FOR DEVELOPMENT SO SYSTEM HAS A MEDIUM...30
PERCENT...CHANCE OF STRENGTHENING.  MODEL GUIDANCE KEEPS
CIRCULATION GOING FOR NEXT 48 HOURS...BUT MAINTAIN SURFACE WINDS
BELOW TROPICAL STORM THRESHOLD. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH EXTENDS FROM 10N85W TO 08N94W TO 1009 MB LOW PRES 
AT 13N120W.  ITCZ  FROM 13N133W TO BEYOND 12N140W.  SCATTERED
MODERATE CONVECTION WITHIN 240 NM S OF AXIS FROM 104W TO 118W
THEN WITHIN 120 NM OF AXIS TO BEYOND 140W. 

...DISCUSSION...                                       
SHARP UPPER LEVEL TROUGH EXTENDS ACROSS NW CORNER OF BASIN AND
BRINGS LARGE REGION OF DRY STABLE AIR MASS INTO E PAC N OF 20N
W OF 120W.  UPPER LEVEL ANTICYCLONE OVER...RECENTLY DOWNGRADED...
TROPICAL STORM GIL BRINGS RIDGE EASTWARD OVER SURFACE LOW PRES
1010 MB AT 13N120W AND BEYOND TO 12N112W. PLENTY OF WARM TROPICAL
MOISTURE FOCUSES ALONG MONSOON TROUGH FROM 104W TO 118W...BUT
CONVECTION MAINLY NOTED W OF 1008W IN PROXIMITY OF BOTH
AFOREMENTIONED SYSTEMS.  

UPPER LEVEL CYCLONE AT 21N116W HAS TROUGH TO 15N108W TO 08N96W 
SPLITTING RIDGE AND ALLOWING SCATTERED MODERATE CONVECTION ALONG
MONSOON TROUGH E OF 88W. 

...ELSEWHERE AT THE LOWER LEVELS...
SURFACE RIDGE N AND W OF BASIN MAINTAINS AREA OF FRESH NE TRADES
FROM 09N TO 21N W OF 135W WITH SEAS TO 10 FT IN NE SWELL.  AREA
QUICKLY DIMINISH IN COVERAGE AS TROPICAL STORM GIL MOVES W...
EVENTUALLY MERGING.  

$$ 
WALLY BARNES