000
AXPZ20 KNHC 100244
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
0405 UTC SAT AUG 10 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...   

A LOW PRESSURE CENTER 1008 MB AT 11N117W MOVING W AT 10 KT 
APPROACHES REGION OF MODERATE EASTERLY VERTICAL SHEAR WHILE 
CONTINUING OVER WARM SEA SURFACE TEMPERATURE AND INTO A MOIST 
ATMOSPHERE.  ENVIRONMENT IS MODERATELY CONDUCIVE FOR 
DEVELOPMENT.  NHC HAS GIVEN IT A MEDIUM CHANCE TO DEVELOP INTO 
TROPICAL CYCLONE OVER THE NEXT 48 HOURS AND A HIGH CHANCE WITHIN 
THE NEXT FIVE DAYS. 
                       
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...        
MONSOON TROUGH EXTENDS FROM 10N85W TO 15N110W TO 1008 MB LOW 
PRES AT 11N117W TO 13N127W TO LOW PRES 1009 MB AT 10N132W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 180 NM OF 
TROUGH 115W TO 130W.  SCATTERED MODERATE CONVECTION FROM 08N TO 
12N BETWEEN 108W TO 113W.  

...DISCUSSION... 
ANOTHER WEAK LOW PRESSURE CENTER IS AT 10N132W AND REMAINS UNDER 
MODERATE NORTHEASTERLY SHEAR AND WARM SEA SURFACE TEMPERATURES 
AND ABUNDANT TROPICAL MOISTURE.  SOUTHEAST OF THE LOW...THERE 
HAS BEEN AN ONGOING LOW-LEVEL SW SURGE INTO THE MONSOON TROUGH.  
THIS HAS ENHANCED THE DEEP CONVECTION AS MENTIONED ABOVE...BUT 
HAS NOT YET INDUCED CYCLOGENESIS.  NHC HAS GIVEN IT A LOW CHANCE 
TO DEVELOP INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AND 
A MEDIUM CHANCE DURING THE NEXT FIVE DAYS.  IT WILL LIKELY CROSS 
W OF 140W IN ABOUT 42 HOURS. 

...ELSEWHERE AT THE LOWER LEVELS... 
A RELATIVELY WEAK STATIONARY HIGH PRESSURE OF 1022 MB W OF AREA 
IS LOCATED NEAR 36N143W WITH A RIDGE EXTENDING SE TO 20N108W.  
AS THE PRESSURE GRADIENT BETWEEN THE HIGH AND THE MONSOON TROUGH 
IS WEAK...THE TRADEWINDS ARE BELOW OUR 25 KT THRESHOLD FOR THE 
HIGH SEAS.

...UPPER LEVELS... 
SUBTROPICAL RIDGING DOMINATES THE BASIN ALONG 
19N140W TO 25N110W WITH E TO NE FLOW PREVAILING ON THE 
EQUATORWARD SIDE.  A LARGE UPPER LOW NEAR 11N106W IS 
RETROGRADING WESTWARD SOUTH OF THE SUBTROPICAL RIDGE.  A WEAK 
MID-LATITUDE TROUGH EXTENDS FROM 29N120W NORTH-NORTHWESTWARD TO 
A CLOSED LOW OVER N CALIFORNIA...BUT IS PRODUCING NO SIGNIFICANT 
WEATHER IN OUR AREA OF RESPONSIBILITY.
 
$$ 
CHRIS LANDSEA