000
AXPZ20 KNHC 012126
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.

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

THE MONSOON TROUGH AXIS IS ANALYZED FROM 09N83W TO 07N88W TO LOW 
PRES NEAR 08N93W TO 06N96W. ITCZ AXIS IS ANALYZED FROM 06N96W TO 
05N100W 09N115W TO 07N130W TO BEYOND 10N140W. SCATTERED MODERATE 
CONVECTION LIES WITHIN 90 NM N OF THE AXIS BETWEEN 122W AND 125W.
 
...DISCUSSION...

AN AMPLIFIED NORTHERN STREAM PATTERN IS IN PLACE WITH A DEEP 
TROUGH OVER NW MEXICO AND THE INTERIOR WESTERN U.S. AHEAD OF 
RIDGING ALONG 135W. THE TROUGH IS PROVIDING UPPER SUPPORT TO A 
COLD FRONT THAT CURRENTLY EXTENDS FROM 27N113W INTO THE PACIFIC 
TO 26N120W. THE FRONT WILL WEAKEN AS IT CONTINUES SOUTH... 
DISSIPATING BY FRI AFTERNOON. FRESH TO STRONG N WINDS FOLLOW THE 
FRONT ACCOMPANIED BY N SWELL WITH SIGNIFICANT WAVE HEIGHTS TO 16 
FT AS SEEN BY SHIP A8KZ4 NEAR 29N123W AND SHIP C6YA7 NEAR 
30N126W AT 1800 UTC. WHILE WINDS WILL GRADUALLY DIMINISH TO 
FRESH AND SHIFT WESTWARD...THE SEAS WILL REACH 10 FT OR MORE 
OVER MUCH OF THE AREA N OF 20N W OF 120W THROUGH SAT. STRONG 
HIGH PRES BUILDING BEHIND THE FRONT WILL ALSO SUPPORT FRESH 
TRADES OVER WESTERN WATERS...PARTICULARLY N OF 13N AND W OF 
130W. 

THE FRONT IS ALSO PUSHING THROUGH INTO GULF OF CALIFORNIA FROM 
29N111W TO 27N113W. A 1734 UTC ASCAT PASS INDICATED 20 KT SW 
FLOW AHEAD OF THE FRONT AS FAR S AS 26N. FRESH NW WINDS LIE 
BEHIND THE FRONT...WITH THE OBSERVATION STATION AT SAN FELIPE 
BRIEFLY REACHING 25 KT AT 1800 UTC. THE FRONT WILL DISSIPATE BY 
FRI AFTERNOON AND WINDS ARE EXPECTED TO DIMINISH BY FRI EVENING.

A SURFACE LOW LIES ALONG THE MONSOON TROUGH NEAR 08N93W 
WITH AND ESTIMATED PRES OF 1010 MB. THE LOW IS EXPECTED TO MOVE 
W AT 10-15 KT OVER THE NEXT COUPLE OF DAYS AND INTENSIFY 
SLIGHTLY. FRESH TO STRONG WINDS ARE EXPECTED PRIMARILY WITHIN 
150 NM NE SEMICIRCLE OF THE LOW CENTER WITH BUILDING SEAS TO 10 
FT BY SAT AFTERNOON. 

GULF OF TEHUANTEPEC...THE 1556 ASCAT PASS MISSED THE GULF OF 
TEHUANTEPEC BUT CAPTURED 20 KT WINDS AS FAR AWAY AS 12N98W. 
FRESH TO STRONG GAP FLOW WILL CONTINUE INTO THE WEEKEND AS HIGH 
PRES REMAINS STRONG OVER THE GULF OF MEXICO.

GULF OF PAPAGAYO...OVERNIGHT DRAINAGE WILL 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 
STRONGEST DURING THE OVERNIGHT AND EARLY MORNING HOURS. 

$$
SCHAUER/CHRISTENSEN