000
AXPZ20 KNHC 021538
TWDEP 

TROPICAL WEATHER DISCUSSION                                   
NWS NATIONAL HURRICANE CENTER MIAMI FL                       
1605 UTC SAT AUG 02 2014

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 FEATURES...

HURRICANE ISELLE IS CENTERED NEAR 15.0N 129.2W AT 02/1500 UTC OR 
ABOUT 1190 NM...2205 KM WSW OF THE SOUTHERN TIP OF BAJA 
CALIFORNIA MOVING W OR 280 DEGREES AT 9 KT. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 987 MB. MAXIMUM SUSTAINED WIND SPEED IS 70 
KT WITH GUSTS TO 85 KT. NUMEROUS STRONG CONVECTION IS OBSERVED 
WITHIN 60 NM N SEMICIRCLE AND 120 NM SE QUADRANT OF CENTER. 
NUMEROUS MODERATE CONVECTION IS ALSO NOTED ELSEWHERE FROM 13N TO 
16N BETWEEN 127W AND 131W. THE OFFICIAL INTENSITY FORECAST CALLS 
FOR ISELLE TO MAINTAIN HURRICANE STATUS THROUGH TUE. PLEASE SEE 
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/ 
WTPZ24 KNHC FOR MORE DETAILS.  

CONVECTION CONTINUES TO DEVELOP IN THE VICINITY OF LOW PRES 
LOCATED NEAR 13N113W 1008 MB...ALONG THE MONSOON TROUGH. 
NUMEROUS MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 
120 NM W SEMICIRCLE OF LOW CENTER. A CLUSTER OF MODERATE TO 
STRONG CONVECTION IS TO THE NORTH OF CENTER FROM 14N TO 17N 
BETWEEN 111W AND 113W. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE 
FOR FURTHER DEVELOPMENT...AND THIS SYSTEM MAY DEVELOP INTO A 
TROPICAL CYCLONE OVER THE NEXT 48 HOURS AS IT CONTINUES TO MOVE 
WESTWARD AT 9 KT.  
                           
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
 
MONSOON TROUGH EXTENDS FROM 09N84W TO 07N95W TO 1008 MB LOW PRES 
NEAR 13N113W TO 10N120W...THEN RESUMES SW OF HURRICANE ISELLE 
FROM 13N131W TO 12N140W. NUMEROUS MODERATE TO STRONG FROM 04N TO 
08N BETWEEN 79W AND 82W...AND FROM 06N TO 09N BETWEEN 82W AND 
85W. SCATTERED MODERATE WITHIN 150 NM S OF TROUGH BETWEEN 88W 
AND 100W. SIMILAR CONVECTION IS FROM 06N TO 10N BETWEEN 103W AND 
106W.

...DISCUSSION...

A BROAD UPPER ANTICYCLONIC CIRCULATION IS CENTERED NEAR 20N 140W 
WITH A RIDGE EXTENDING EASTWARD TO 125W. MODERATE TO STRONG 
UPPER LEVEL SUBSIDENCE AND IMPLIED DRY AIR MASS IS SEEN ON WATER 
VAPOR IMAGERY WITHIN THE RIDGE. BROAD AND WEAKENING UPPER 
TROUGHING IS ALONG 30N122W TO 24N121W TO 18N123W. ANOTHER UPPER 
ANTICYCLONE IS CENTERED NEAR 16N112W AND TO THE N OF THE LOW 
PRES LOCATED NEAR 13N113W. FARTHER EAST...AN UPPER CYCLONE IS 
CENTERED OVER THE NW CARIBBEAN...WITH A TROUGH REACHING AS FAR 
SOUTH AS 13N90W. DIVERGENT FLOW ALOFT ON THE SE SIDE OF THIS 
TROUGH IS ENHANCING CONVECTION ALONG THE MONSOON TROUGH E OF 
85W. 
 
A 1009 MB LOW PRES HAS MOVED W OF AREA AND NOW IS LOCATED NEAR 
12N141W. PRES GRADIENT BETWEEN THE LOW AND THE RIDGE TO THE N IS 
STILL PRODUCING A SMALL AREA OF FRESH TO STRONG TRADE WINDS FROM 
12N TO 18N W OF 134W...WITH SEAS TO AROUND 9 FT. SEAS ARE 
FORECAST TO GRADUALLY INCREASE ACROSS THE W-CENTRAL WATERS... 
PARTICULARLY FROM 11N TO 21N W OF 130W AHEAD OF TROPICAL 
CYCLONE ISELLE.
         
EXPECT FRESH WINDS ACROSS THE GULF OF PAPAGAYO OVERNIGHT TONIGHT 
AND EARLY SUN MORNING...WITH SEAS OF 6-7 FT.
 
$$ 
GR