000
AXPZ20 KNHC 271549
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU OCT 27 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 
1500 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 10N86W TO 07N96W TO 11N110W. THE 
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N110W TO 
11N122W. SCATTERED MODERATE CONVECTION IS FROM 07N TO 17N 
BETWEEN 118W AND 131W.

...DISCUSSION...

A SHARP UPPER LEVEL TROUGH REACHES FROM NEAR POINT CONCEPTION 
CALIFORNIA TO 32N128W TO AN UPPER LEVEL CYCLONE NEAR 27N134W TO 
19N136W THEN SOUTH TO A BASE OVER THE DEEP TROPICAL PACIFIC NEAR 
09N135W. AN UPPER LEVEL ANTICYCLONE IS OVER THE E PACIFIC 
CENTERED NEAR 16N115W WITH RIDGING EXTENDING NW TO NEAR 27N128W. 
CONVECTION REMAINS ACTIVE DUE TO UPPER LEVEL DIFFLUENCE IN THE 
REGION EAST OF THE UPPER LEVEL TROUGH FROM 07N TO 17N BETWEEN 
118W AND 135W.

WITH THE UPPER LEVEL TROUGH IN PLACE ACROSS THE WESTERN PORTION 
OF THE FORECAST WATERS...A SURFACE TROUGH IS ANALYZED FROM 
18N131W TO 11N133W. AN OVERNIGHT WINDSAT PASS AROUND 27/0236 UTC 
AND RECENT GLOBAL MODEL DATA INDICATE FRESH NE TO E WINDS FROM 
14N TO 21N W OF 132W IN THE VICINITY OF THE SURFACE TROUGH...AND 
FRESH NW TO N WINDS FROM 19N TO 27N BETWEEN 110W AND 118W WHERE 
A TIGHT PRESSURE GRADIENT EXISTS...ALONG WITH 8 TO 10 FT SEAS IN 
MIXED NE AND NW SWELL. THE TROUGH WILL MOVE W OF THE AREA BY 24 
HOURS WITH THE AREA OF FRESH WINDS BECOMING CONFINED TO THE AREA 
FROM 14N TO 22N W OF 129W AT THAT TIME IN THE WAKE OF THE 
TROUGH...AND THE PRESSURE GRADIENT RELAXING JUST WEST OF THE 
SOUTHERN BAJA CALIFORNIA COAST.

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS SE FROM HIGH PRESSURE 
N OF THE AREA NEAR 37N134W TO 32N128W TO 16N110W. A TIGHT PRES 
GRADIENT IS ALSO EXISTS OVER THE BAJA CALIFORNIA REGION BETWEEN 
THIS RIDGE AND A DEEPENING SURFACE LOW PRESSURE AREA OVER 
NORTHERN MEXICO. AS A RESULT...FRESH NORTHERLY WINDS WILL 
GRADUALLY SPREAD SOUTHWARD IN THE GULF OF CALIFORNIA REACHING TO 
24N WITHIN 24 HOURS...THEN WILL DIMINISH OVER THE CENTRAL GULF 
OF CALIFORNIA AND BE CONFINED TO 20 KT WINDS N OF 30N BY 48 
HOURS AS THE SURFACE LOW WEAKENS AND SHIFTS W TO THE MEXICAN 
COASTLINE. SEAS WILL REMAIN LESS THAN 8 FT THROUGH 48 HOURS.

MODEL GUIDANCE DEPICTS FRESH SW FLOW S OF THE MONSOON TROUGH 
FROM 24 HOURS THROUGH THE REMAINDER OF THE FORECAST PERIOD... 
I.E. 48 HOURS...OVER THE FAR SE PORTION OF THE AREA WITH SEAS 
BUILDING TO 8 FT.
 
GAP WINDS...A STRONG COLD FRONT WILL MOVE THROUGH THE SW GULF OF 
MEXICO ON FRI RESULTING IN A STRONG SURGE OF NORTHERLY WINDS 
WHICH WILL FUNNEL THROUGH THE CHIVELA PASS BEHIND THE FRONT. 
WINDS WILL ARRIVE IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
AROUND SUNSET FRI QUICKLY INCREASING TO GALE FORCE AROUND 
MIDNIGHT WHEN A GALE WARNING WILL COMMENCE. SEAS WILL RAPIDLY 
BUILD TO UP TO 13 FT IN THE AREA OF GALE FORCE WINDS.
 
$$
HUFFMAN