Eastern Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 011547
TWDEP 

TROPICAL WEATHER DISCUSSION                                   
NWS NATIONAL HURRICANE CENTER MIAMI FL                       
1605 UTC FRI AUG 01 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...

T.S. ISELLE CENTERED NEAR 14.1N 125.7W AT 01/1500 UTC MOVING  
WEST-NORTHWEST OR 295 DEGREES AT 9 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 998 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH 
GUSTS TO 65 KT. NUMEROUS MODERATE TO STRONG CONVECTION IS NOTED 
WITHIN 120 NM E SEMICIRCLE OF THE CENTER. ISELLE IS 
STRENGTHENING A LITTLE MORE...AND IS EXPECTED TO BECOME A 
HURRICANE LATER TODAY OR TONIGHT. PLEASE SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC 
FOR MORE DETAILS.   

A TROPICAL WAVE EXTENDS FROM 18N111W TO A 1008 MB LOW PRES 
LOCATED WITHIN THE MONSOON TROUGH NEAR 12N110.5W. CONVECTION 
ASSOCIATED WITH THE LOW PRES HAS SLIGHTLY INCREASED DURING THE 
LAST FEW HOURS. NUMEROUS MODERATE TO STRONG CONVECTION IS NOTED 
FROM 11N TO 13N BETWEEN 110W AND 112W. SCATTERED MODERATE 
CONVECTION IS ELSEWHERE FROM 10N TO 14N BETWEEN 109W AND 112W. 
AN EARLIER ASCAT PASS ALONG WITH AN ALTIMETER PASS INDICATED 
LIMITED WINDS AND SEAS ASSOCIATED WITH THIS LOW. ENVIRONMENTAL 
CONDITIONS ARE CONDUCIVE FOR GRADUAL DEVELOPMENT OF THIS 
SYSTEM...AND THE LATEST NHC TROPICAL WEATHER OUTLOOK GIVES THIS 
LOW PRES AREA A MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL 
CYCLONE DURING THE NEXT 48 HOURS WHILE IT MOVES WESTWARD AT 
ABOUT 10 KT.

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

MONSOON TROUGH EXTENDS FROM 08N78W TO 07N81W TO 09N88W TO 08N98W 
TO 1008 MB LOW PRES NEAR 12N110.5W TO 14N120W...THEN RESUMES SW 
OF T.S. ISELLE NEAR 14N125W TO 1008 MB LOW PRES NEAR 12N137W TO  
12N140W. A CLUSTER OF MODERATE CONVECTION IS FROM 03N TO 06N E 
OF 78W. ANOTHER CLUSTER OF MODERATE TO ISOLATED STRONG 
CONVECTION IS FROM 07N TO 09N BETWEEN 85W AND 88W. SCATTERED 
MODERATE CONVECTION IS NOTED FROM 03N TO 07N BETWEEN 78W AND 
85W. SIMILAR CONVECTION CAN BE FOUND FROM 10N TO 14N BETWEEN 
105W AND 109W...AND FROM 11N TO 14N BETWEEN 128W AND 131W.  

...DISCUSSION...

AN ANTICYCLONIC CIRCULATION LOCATED NEAR 19N139W EXTENDS A RIDGE 
NE TO NEAR 26N124W. THIS SYSTEM DOMINATES THE AREA N OF 15N W OF 
125W WHERE MODERATE TO STRONG SUBSIDENCE IS SEEN ON WATER VAPOR 
IMAGERY. ANOTHER ANTICYCLONE IS CENTERED NEAR 15N110W. IN 
BETWEEN...THERE IS AN UPPER-LEVEL TROUGH THAT EXTENDS FROM 
30N122W TO 22N121W TO 18N125W. A CYCLONIC CIRCULATION IS VERY 
CLOSE TO THE SOUTHERN TIP OF BAJA CALIFORNIA NEAR 23N111W. AN 
UPPER-LEVEL LOW SPINNING OVER THE NW CARIBBEAN HAS A TROUGH 
EXTENDING ACROSS NORTHERN CENTRAL AMERICA INTO THE EPAC TO NEAR 
07N90W. UPPER DIFFLUENCE AHEAD OF THIS TROUGH IS HELPING TO 
INDUCE CONVECTION E OF 88W. 

CONVECTION HAS DIMINISHED CONSIDERABLY AROUND THE LOW PRES 
LOCATED NEAR 12N137W AND NOW IS PRODUCING MINIMAL SHOWER 
ACTIVITY. HOWEVER AN ASCAT SATELLITE PASS INDICATED 20 TO 25 KT 
WINDS BETWEEN THIS LOW AND THE SUBTROPICAL RIDGE TO THE NORTH. 
SEAS ARE ESTIMATED TO BE UP TO 9 FT IN MIXED SE AND NE SWELL 
OVER THE NEXT 24 TO 36 HOURS N OF THIS LOW AS IT DRIFTS W OF 
140W.

FRESH TO LOCALLY STRONG WINDS CONTINUE TO PULSE ACROSS THE GULF 
OF PAPAGAYO DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH 
SEAS OF 6-7 FT. THIS WEATHER PATTERN WILL PERSIST OVER THE NEXT 
48 HOURS.  

$$ 
GR