000
AXPZ20 KNHC 010934
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU DEC 01 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

MONSOON TROUGH AXIS FROM 09N85W TO 08N90W. ITCZ AXIS FROM 08N90W 
TO 09N115W TO 11N140W. NO DEEP CONVECTION.
 
...DISCUSSION...

THE UPPER PATTERN OVER THE FORECAST AREA WILL BECOME MORE 
AMPLIFIED THROUGH FRI EVENING AS A VIGOROUS UPPER TROUGH OVER 
CALIFORNIA DIGS INTO NW MEXICO AHEAD OF RIDGING BUILDING NEAR 
140W. AN UPPER LOW CENTERED NEAR 30N137W IS WEAKENING TO THE 
SOUTH OF A BUILDING UPPER ANTICYCLONE NEAR 39N139. THE UPPER LOW 
WILL DISSIPATE THU AS THE UPPER TROUGH DIGS INTO THE NORTHERN 
BAJA PENINSULA AND NW MEXICO. THIS TROUGH IS SUPPORTING A COLD 
FRONT CURRENTLY CLIPPING THE NORTH WATERS. THE FRONT IS FORECAST 
TO MOVE SE AND EXTENDS FROM FROM 31N113W TO 24N120W TONIGHT AND 
BEGIN TO DISSIPATE FROM FROM 27N110W TO 17N122W BY FRI NIGHT.   
FRESH TO STRONG N WINDS WILL FOLLOW THE FRONT THU ACCOMPANIED BY 
N SWELL WITH SIGNIFICANT WAVE HEIGHTS TO 15 FT PER MARINE 
GUIDANCE. STRONG HIGH PRES BUILDING BEHIND THE FRONT WILL ALSO 
SUPPORT FRESH TRADES OVER WESTERN WATERS...PARTICULARLY N OF 15N 
AND W OF 130W.

ANOTHER UPPER TROUGH CURRENTLY LIES S OF 23N ALONG 115W WITH A 
LARGE STATIONARY ANTICYCLONE TO ITS E CENTERED OVER NICARAGUA. 
SW FLOW AHEAD OF THE UPPER TROUGH IS TRANSPORTING MID/UPPER 
LEVEL MOISTURE FROM THE EPAC INTO N-CENTRAL MEXICO.

A SURFACE LOW IS FORECAST TO DEVELOP ALONG THE MONSOON TROUGH 
AND MOVE W-NW OVER THE NEXT COUPLE OF DAYS. WINDS OF 20 KT ARE 
EXPECTED WITHIN 120 NM N AND NE QUADRANT OF LOW CENTER WITH 
BUILDING SEAS TO 10 FT IN E SWELL. 

GAP WINDS...
GULF OF CALIFORNIA...FRESH TO STRONG SW WINDS N OF 29N WILL 
PROCEED THE APPROACHING COLD FRONT OVER THE NORTHERN GULF 
BEGINNING EARLY THU MORNING AND SHIFT NW BEHIND THE FRONT THU. 
THE FRONT WILL WEAKEN FRI AS IT REACHES AS FAR S AS 27N BEFORE 
DISSIPATING. 

GULF OF TEHUANTEPEC...THE 0322 ASCAT PASS AND A SHIP OBSERVATION 
SHOWED WINDS TO 30 KT. A SLIGHT INCREASE IN WINDS IS EXPECTED 
EARLY THIS MORNING DUE TO DRAINAGE IMPACTS. A GALE WARNING 
REMAINS IN EFFECT THROUGH THIS MORNING AS A RESULT.

GULF OF PAPAGAYO...OVERNIGHT DRAINAGE WILL ALSO IMPACT THE GULF 
OF PAPAGAYO...WITH THE ADDED ENHANCEMENT OF STRONG GRADIENT FLOW 
OVER THE SW CARIBBEAN. FRESH TO STRONG NORTHEASTERLY GAP WINDS 
ARE EXPECTED DURING THE NEXT COUPLE OF DAYS. THE WINDS ARE 
GREATEST DURING THE OVERNIGHT AND EARLY MORNING HOURS. 

$$
GR/JS