000
AXPZ20 KNHC 132121
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT AUG 13 2011

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...

A 1008 MB LOW IS LOCATED NEAR 12N123W. WITHIN 270 NM NW AND 90 
NM SE SEMICIRCLES OF THE LOW WINDS ARE 20 TO 25 KT AND SEAS 8 TO 
10 FT. SCATTERED MODERATE TO STRONG CONVECTION IS LOCATED WITHIN 
180 NM OVER THE W SEMICIRCLE. THE LOW IS FORECAST TO TRACK W AND 
HAS A HIGH CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE 
NEXT TWO DAYS.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH 10N83W TO 12N96W TO 09N101W TO LOW PRES 12N123W 
TO 10N135W. ITCZ AXIS 10N135W TO BEYOND 10N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS LOCATED N OF 04N E OF 
105W...WITHIN 90 NM OF 07.5N112.5W...AND WITHIN 60 NM OF LINE 
08N123W TO 10N140W.

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED IN THE 
VICINITY OF 20N142W WITH A RIDGE AXIS EXTENDING NE THROUGH 
32N125W. MODERATE TO STRONG SOUTHWESTERLY WINDS ALOFT ARE 
LOCATED N OF THE RIDGE N OF 25N W OF 130W WITH SPEEDS OF UP TO 
50 KT. WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE FROM 13N 
TO 26N W OF 128W. A MIDDLE/UPPER LEVEL CYCLONIC CIRCULATION IS 
CENTERED NEAR 30N119W WITH A SHARP TROUGH AXIS EXTENDING SW TO 
NEAR 20N128W. MOVING DOWNSTREAM BROAD RIDGING ALOFT IS LOCATED N 
OF 18N E OF 115W INTO MEXICO. A SMALL MIDDLE/UPPER LEVEL 
CYCLONIC CIRCULATION IS CENTERED NEAR 17N120W AND IS MOVING W 
ABOUT 15 KT. MODERATE WESTERLY WINDS ALOFT ARE LOCATED S OF 12N 
W OF 110W. AT THE SURFACE A 1023 MB HIGH IS POSITIONED AT 
34N133W WITH A RIDGE AXIS EXTENDING SE FROM THE HIGH TO NEAR 
22N118W. A SURFACE TROUGH IS LOCATED ALONG 136W FROM 17N TO 
20N.  

LIGHT TO MODERATE EASTERLY TO NORTHEASTERLY FLOW ALOFT IS 
LOCATED FROM THE EQUATOR INTO MEXICO E OF 110W WITH SATELLITE 
CLOUD DRIFT WINDS INDICATING SPEEDS OF UP TO 30 KT. FROM 03N TO 
08N BETWEEN 95W AND 115W S TO SW WINDS ARE 20 KT WITH SEAS TO 10 
FT PRIMARILY IN SW SWELL. ELSEWHERE S OF 15N E OF 102W AND ALSO 
S OF 08N BETWEEN 102W AND 117W WINDS ARE LESS THAN 20 KT WITH 
SEAS 8 TO 11 FT PRIMARILY IN SW SWELL.

$$
CAB