000
AXPZ20 KNHC 032201
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.
 
...ITCZ/MONSOON TROUGH...

MONSOON TROUGH AXIS EXTENDS FROM 10N86W TO 9N97W TO 13N112W TO 
8N134W WHERE LOW LEVEL WINDS INDICATE THAT THE ITCZ AXIS BEGINS 
AND EXTENDS TO BEYOND 8N140W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 270 NM OF THE TROUGH AXIS BETWEEN 
89W-101W...AND WITHIN 75 NM S OF THE TROUGH BETWEEN 118W-122W.
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE TROUGH W OF
128W.

...DISCUSSION...

...N OF 18N... 

WESTERLY FLOW ALOFT IS NOTED THROUGHOUT MOST OF THIS PORTION OF 
THE DISCUSSION AS A RATHER SHARP DEEP LAYER TROUGH THAT EXTENDS
FROM 32N125W SW TO NEAR 22N135W MOVES TOWARDS THE WEST COAST OF 
THE U.S. THE TROUGH IS FORECAST TO MOVE INLAND THE W COAST 
OVERNIGHT INTO TUE...AND ACROSS THE WESTERN U.S. THROUGH WED. 
THE TAIL END OF THE TROUGH IS FORECAST TO SHEAR OFF AND DEVELOP 
INTO A CYCLONIC CIRCULATION THAT MOVES WESTWARD TO NEAR 19N140W 
BY TUE NIGHT.

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. IT EXTENDS 
FROM 32N128W SW TO 28N136W WHERE IT BEGINS TO DISSIPATE TO NEAR
28N140W. BROKEN LOW/MID CLOUDS WITH SCATTERED SHOWERS ARE WITHIN
50-60 NM OF THE FRONT. THE FRONT IS FORECAST TO BEGIN TO 
DISSIPATE AS IT REACHES FROM NEAR 30N122W TO 25N135W IN 24 
HOURS...THEN WASH OUT IN 48 HOURS AS IT LOSES ITS UPPER SUPPORT 
AS THE UPPER TROUGH MOVES INLAND. WINDS NW OF THE FRONT WILL BE 
LESS THAN 20 KT...BUT A NW SWELL WILL BUILD SEAS UP TO 8 OR 9 FT.

A WEAK 1017 MB LOW...REMNANTS OF HILARY...IS ANALYZED NEAR 
22N126W MOVING SLOWLY WESTWARD. VISIBLE SATELLITE IMAGERY FROM
THROUGHOUT THE DAY SHOWED A SWIRL OF MOSTLY BROKEN LOW/MID 
CLOUDS WITHIN 200 NM IN THE NW SEMICIRCLE OF THE LOW...AND 
MOSTLY SCATTERED LOW CLOUDS WITHIN 180 NM IN THE SE SEMICIRCLE. 
WIDELY SCATTERED SHOWERS ARE POSSIBLE UNDERNEATH THESE CLOUDS. 
HIGH PRES RIDGING IS BRIDGING SOUTHEASTWARD ACROSS THE THE FRONT 
FROM 27N140W TO 28N127W AND SE TO 25N118W. HIGH PRES COVERS THE 
AREA N OF 22N W OF 120W.

...S OF 18N...

UPPER ANTICYCLONIC FLOW...MOSTLY INDUCED BY MONSOON CONVECTION
...DOMINATES THIS AREA OF THE REGION. THE MID/UPPER LEVEL 
RIDGE EXTENDS E TO W FROM AN ANTICYCLONE ALONG THE N COAST OF 
HONDURAS WESTWARD ALONG 16N TO A COL REGION AT 131W. ANOTHER 
MID/UPPER RIDGE EXTENDS ALONG 15N W OF THE COLD REGION.

ABUNDANT DEEP LEVEL ATMOSPHERIC ALONG AND NEAR THE MONSOON TROUGH
IS FURTHER AIDED BY DIFFLUENCE ALOFT ALONG THE MID/UPPER RIDGE.

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 TO EVENTUALLY DEVELOP A 
LOW SW OF THE GULF OF TEHUANTEPEC WITHIN ABOUT 24 HRS NEAR 
10N105W WITH A PRES OF 1009 MB. THE LOW IS FORECAST TO BE NEAR
11N109W IN 48 HRS AT WHICH TIME WINDS OF 20-25 KT ARE FORECAST
TO BE WITHIN 120 NM OF THE LOW IN THE N QUADRANTS AND 270 NM IN
THE S SEMICIRCLE WITH SEAS TO 9 FT. PRIOR TO THE 48 HRS...NE-E 
WINDS OF 20 KT TEHUANTEPEC DOWNSTREAM WINDS WILL BE CONFINED 
FROM 10N-14N BETWEEN 100W-105W AND SW-W 20 KT WINDS WILL FROM 
5N-10N BETWEEN 97W-110W WITH SEAS TO 9 FT.

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 113W-128W IN 18 HOURS...S OF
4N BETWEEN 108W-130W IN 24 HRS...THEN MERGED INTO SEAS RELATED
TO NEW LOW FORECAST TO DEVELOP AS DESCRIBED ABOVE. THE SWELLS 
WILL BUILD THE SEAS UP TO 8 FT STARTING TUE MORNING AND INTO
WED EVENING. ANOTHER AREA OF SW SWELLS WITH SEAS TO 8 FT IS 
FORECAST TO MATERIALIZE FROM 8N-22N W OF 135W IN ABOUT 48 HRS.

$$
AGUIRRE