000
AXPZ20 KNHC 080923
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT DEC 08 2012

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 
0915 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 08N78W TO 07N90W. ITCZ EXTENDS 
FROM 08N95W TO 12N105W TO 07N140W. SCATTERED MODERATE CONVECTION 
WITHIN 45 NM OF ITCZ AXIS W OF 130W.

...DISCUSSION...

FRESH TO STRONG N WINDS PERSIST N OF 30N E OF 125W TO THE COAST 
OF CALIFORNIA...ON THE SE PERIPHERY OF 1030 MB HIGH PRES 
CENTERED NEAR 40N135W. SEAS TO 9 FT IN NE SWELL ARE PENETRATING 
AS FAR S AS 27N BETWEEN 118W AND 130W. A CUT OFF UPPER LOW IS 
CENTERED NEAR 29N141W. A 19 UTC ASCAT INDICATED AN ASSOCIATED 
SURFACE TROUGH NEAR 28N135W. WITH THIS SURFACE TROUGH IN 
PLACE...TRADES WINDS FARTHER SOUTH HAVE BEEN GENERALLY 15 TO 20 
KT IN AN AREA FROM 08N TO 21N W OF 130W. SEAS IN THIS SAME AREA 
ARE STILL ESTIMATED TO BE 8 TO 9 FT IN A MIX OF FRESH NE AND 
LONGER PERIOD NW SWELL. 

A BLOCKING PATTERN WILL DEVELOP IN THE MID TO UPPER LEVELS 
THROUGH EARLY NEXT WEEK AS A BROAD RIDGE DEVELOPS N OF THE UPPER 
LOW...REINFORCING THE SURFACE HIGH PRES N OF THE AREA AND 
DEVELOPING A ARC OF NE WINDS FROM CENTRAL CALIFORNIA THROUGH THE 
NW CORNER OF THE DISCUSSION AREA NEAR 30N140W BY LATE SUN. FRESH 
NE SWELL WILL ACCOMPANY THE NE WINDS...WITH SEAS BUILDING TO 9 
FT. LOOKING AHEAD TO THE MIDWEEK...THE BLOCKING PATTERN BREAKS 
DOWN AS A TROUGH DIGS E THROUGH THE GULF OF ALASKA THE SE TO 
WASHINGTON/OREGON...ERODING THE DEEP LAYER RIDGE. THE SURFACE 
HIGH PRES WEAKENS SLIGHTLY AND SHIFTS W IN RESPONSE...ALLOWING 
WINDS TO 25 KT NEAR 30N140W BY WED.

A SHARP NEGATIVELY TILTED UPPER TROUGH PERSISTS FROM 20N123W TO 
06N115W...SUPPORTING SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS FROM 11N TO 17N BETWEEN 112W AND 116W. 

FARTHER EAST...A WEAK SURFACE TROUGH IS ANALYZED NEAR 93W FROM 
05N TO 08N. THIS HAD BEEN SUPPORTED BY EARLIER PULSES OF 
EASTERLY GAP FLOW THROUGH THE GULF OF PAPAGAYO ALONG WITH UPPER 
SUPPORT FROM A SHORT WAVE TROUGH TO THE NE. GLOBAL MODELS SHOW 
THIS FEATURE PERSISTING POSSIBLY AS A WEAK LOW PRES AREA ALONG 
THE MONSOON TROUGH BETWEEN 95W AND 100W INTO EARLY NEXT WEEK. 
ASIDE FROM MODEST CONVECTION AND WINDS TO 20 KT ON THE NORTHERN 
EXTENT OF THE LOW...NO SIGNIFICANT WEATHER IS EXPECTED.  

AN ASCAT PASS FROM 03 UTC INDICATED WINDS TO 20 KT WERE PUSHING 
ACROSS THE ISTHMUS OF PANAMA INTO THE GULF OF PANAMA. AN EARLIER 
PASS INDICATED 20 KT PULSES PERSISTED THROUGH THE GULF OF 
PAPAGAYO AS WELL. 

GULF OF CALIFORNIA...WINDS WILL INCREASE TO 20 TO 25 KT OVER THE 
NORTHERN EXTENT OF THE GULF BY LATE SUN NIGHT INTO EARLY MON 
MORNING AS HIGH PRES BUILDS OVER THE GREAT BASIN N OF THE AREA.

$$
CHRISTENSEN