000
AXPZ20 KNHC 031549
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.
 
...ITCZ/MONSOON TROUGH...

MONSOON TROUGH AXIS EXTENDS FROM 8N83W TO 10N95W TO A 1012 MB 
LOW AT 11N106W TO 8N130W WHERE LOW LEVEL WINDS INDICATE THAT THE 
ITCZ AXIS BEGINS AND EXTENDS TO BEYOND 8N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION WAS NOTED WITHIN 240 NM N OF 
THE TROUGH AXIS BETWEEN 86W-98W...AND N OF 5N E OF 85W. 
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE TROUGH 
BETWEEN 125W-135W.

...DISCUSSION...

...N OF 18N... 

UPPER LEVEL WESTERLY FLOW IS SEEN THROUGHOUT MOST OF THIS 
PORTION OF THE DISCUSSION AREA AS A RATHER SHARP LONGWAVE TROUGH 
N OF 27N AND ALONG 127N SLIDES EASTWARD TOWARDS THE WEST COAST 
OF THE U.S. THE TROUGH IS FORECAST TO MOVE ACROSS THE WESTERN 
U.S. MON THROUGH TUE. THE FAR SOUTHERN PORTION OF THE TROUGH 
SHOULD SHEAR OFF AND LAG BEHIND NEAR 19N139W BY LATE TUE...WHERE 
IT DEVELOPS INTO AN UPPER LOW THAT MOVES WESTWARD.

A LARGE AREA OF HIGH PRES WILL PRESS EASTWARD IN ITS WAKE. AHEAD 
OF THE HIGH...A SURFACE COLD FRONT ASSOCIATED WITH THE TROUGH HAS
MOVED INTO THE NW PORTION OF THE DISCUSSION AREA...AND EXTENDS 
FROM 32N130W SW TO 28N140W WHERE IT BECOMES DIFFUSE. THE FRONT 
IS FORECAST TO BEGIN TO DISSIPATE AS IT REACHES FROM NEAR 
30N123W TO 25N130W IN 24 HOURS THEN WASH OUT IN 48 HOURS AS IT 
LOSES ITS UPPER SUPPORT AS UPPER TROUGH MOVES INLAND. WINDS NW 
OF THE FRONT WILL BE LESS THAN 20 KT...BUT A NW SWELL WILL ALLOW 
FOR SEAS TO REACH 8 OR 9 FT.

A WEAK 1015 MB LOW...REMNANTS OF HILARY...IS ANALYZED NEAR 
23N126W MOVING SLOWLY WESTWARD. EARLY VISIBLE IMAGERY SHOWED
A SWIRL OF MOSTLY BROKEN LOW/MID CLOUDS WITHIN 240 NM IN THE N 
SEMICIRCLE OF THE LOW...AND SCATTERED TO BROKEN LOW CLOUDS 
WITHIN 180 NM IN THE S SEMICIRCLE. WIDELY SCATTERED SHOWERS ARE 
POSSIBLE UNDERNEATH THESE CLOUDS. HIGH PRES RIDGING IS BRIDGING
SOUTHEASTWARD ACROSS THE THE FRONT FROM 28N140W TO NEAR 25N120W.
HIGH PRES COVERS THE AREA N OF 22N W OF 120W.

...S OF 18N...

UPPER ANTICYCLONIC FLOW PREDOMINATES THROUGHOUT THIS AREA AS A 
NEARLY STATIONARY ANTICYCLONES REMAINS ANCHORED NEAR 14N110W WITH
A RIDGE W TO A COLD REGION AT 14N133W...AND ANOTHER RIDGE 
EASTWARD TO ACROSS CENTRAL AMERICA. ABUNDANT DEEP LEVEL 
ATMOSPHERIC MOISTURE AIDED BY DIFFLUENCE ALOFT PERSISTS IN THE 
VICINITY OF THE MONSOON TROUGH PRIMARILY TO THE E OF 126W. A 
1012 MB LOW IS ON THE MONSOON TROUGH NEAR 11N107W. WINDS OF 20 
KT AR WITHIN 180 NM OF THE LOW. THE LOW IS FORECAST TO MOVE TO 
NEAR 12N113W IN 48 HOURS WITH WINDS INCREASING TO 20-25 KT.

N TO NE WINDS TO 30 KT WILL CONTINUE TO FUNNEL INTO THE GULF OF 
TEHUANTEPEC WITHIN 60 NM EITHER SIDE OF A LINE FROM 16N95W TO 
11N99W. THESE WINDS WILL CONTINUE THROUGH THE NEXT 24 HOURS WITH 
SEAS IN THE 8-10 FT RANGE...THEN DECREASE SOME IN 48 HOURS. THE 
DOWNSTREAM NE-E 20 KT WINDS WILL IMPINGE INTO THE MONSOON TROUGH 
OVER THE NEXT 48 HOURS AND PROBABLY HELP DEVELOP A NEW LOW
SW OF THE GULF OF TEHUANTEPEC OVER THE NEXT 36-48 HOURS.
 ELSEWHERE...A WEAK PRES PATTERN WILL REMAIN THROUGH THE NEXT 
COUPLE OF DAYS.

EXPECT CROSS EQUATORIAL SLY SWELLS TO BEGIN TO SPREAD INTO THE 
FAR SOUTHERN WATERS S OF 3N BETWEEN 111W-130W IN 24 HOURS AND S 
OF 9N BETWEEN 95W-125W IN 48 HOURS. THE SWELLS WILL BUILD THE 
SEAS UP TO 9 FT DURING THIS PERIOD.

$$
AGUIRRE