000
AXPZ20 KNHC 012158
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC THU AUG 01 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURES... 
HURRICANE GIL AT 14.3N 125.1W AT 01/2100 UTC MOVING W OR 270 DEG
AT 10 KT.  MAXIMUM SUSTAINED WIND 70 GUSTS TO 85 KT AND MINIMUM
CENTRAL PRES 990 MB.  CURRENTLY...NUMEROUS STRONG CONVECTION IS
WITHIN 90 NM NW AND WITHIN 30 NM SE SEMICIRCLES OF CENTER. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IN BANDS ELSEWHERE
WITHIN 150 NM OF CENTER. GIL STILL REMAINS UNDER FAVORABLE UPPER
LEVEL CONDITIONS AS ANTICYCLONE ALOFT ENHANCES HURRICANE OUTFLOW.
NEVERTHELESS GIL WESTWARD TRACK WILL BRING IT CLOSER TO A REGION
OF INCREASING SW SHEAR AND SEA SURFACE TEMPERATURES ARE JUST N
OF GIL. FORECAST MAINTAINS GIL HOLDING ITS OWN FOR ANOTHER 24-36
HOURS BEFORE THE ONSET OF A WEAKENING TREND. SEE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTNT22 KNHC
FOR ADDITIONAL DETAILS.

LOW PRES CENTER AT 12N116W MOVE W AT 10 KT FOLLOWS IN WAKE OF 
GIL. WHILE UPPER ENVIRONMENT IS SIMILAR TO THE ONE OVER GIL DUE
TO THEIR PROXIMITY...OUTFLOW FROM GIL SEEM TO BE DISRUPTIVE AND
DOES NOT ALLOW ANY SIGNIFICANT INTENSIFICATION OF LOW PRES
CENTER. IT BARELY HOLDS ITS STRENGTH STEADY...NOT QUITE READY TO
BE DISCARDED ALTHOUGH PROBABILITY OF IT BECOMING A TROPICAL
CYCLONE WITHIN THE NEXT 48 HOURS HAS BEEN LOWERED TO 30 PERCENT.
CURRENTLY SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN
150 NM OVER SW SEMICIRCLE. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH AXIS EXTENDS FROM 09N83W TO 12N110W TO 1009 MB
LOW PRES AT 12N116W. ITCZ AXIS STRETCHES FROM 13N130W TO 10N140W.
MODERATE TO STRONG CONVECTION WITHIN 180 NM S OF AXIS E OF 94W
AND WITHIN 120 NM N OF AXIS FROM 127W TO 136W.

...DISCUSSION...                                              
UPPER LEVEL CYCLONE AT 28N148W IS RETREATING W BUT STILL
MAINTAINS TROUGH TO 14N142W AND BRING DRY AIR MASS N OF 20N 
W OF 120W...ALTHOUGH DIMINISHING IN STRENGTH. THIS BRINGS AN 
INTERESTING CONTRAST WITH THE PREVIOUSLY EXPECTED STRONG
SOUTHWESTERLIES TO SHEAR AND DECOUPLE HURRICANE GIL APART.
RESULT MAY BE A SLOWER DECAY OF GIL. LARGE UPPER LEVEL E-W 
QUASI-STATIONARY RIDGE ACROSS CENTRAL E PAC HAS BEEN HOLDING
HURRICANE GIL AND LOW PRES NEAR 13N116W ALIVE BY PROVIDING GOOD
OUTFLOW ENVIRONMENT.  

...AT THE LOWER LEVELS...
BROAD SURFACE RIDGE 1029 MB AT 33N145W MAINTAINS STEADY FLOW OF 
FRESH NE TRADES...BUT NOW DIMINISHING AS RIDGE RETREATS W.
CURRENT SEAS TO 8 FT N OF 18N W OF 120W EXPECTED TO SUBSIDE.

$$ 
WALLY BARNES