000
AXPZ20 KNHC 200341
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE DEC 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 09N84W TO 08N91W THEN ITCZ TO 06N115W TO 
10N128W TO BEYOND 09N140W.  ISOLATED MODERATE CONVECTION WITHIN 
60 NM OF AXIS FROM 96W TO 116W.  SCATTERED MODERATE TO STRONG 
CONVECTION WITHIN 90 NM N OF AXIS W OF 132W. 

...DISCUSSION...
BROAD UPPER LEVEL RIDGE AXIS EXTENDS FROM ANTICYCLONE CENTER AT 
10N109W TO 32N128W PRODUCING DIFFLUENT FLOW WHICH ENHANCES 
CONVECTION ALONG ITCZ FROM 100W TO 110W.  WEAKENING JET STREAM 
...NOW DOWN TO 90 KT...RIDES OVER CREST OF RIDGE ADVECTING 
ABUNDANT MOISTURE UNTO NORTHWESTERN MEXICO AND N PART OF BAJA 
CALIFORNIA.  UPPER LAYER TROUGH EXTENDS FROM STRONG WELL DEFINED 
CYCLONE NEAR FOUR CORNERS THROUGH CENTRAL MEXICO TO GUATEMALA 
AND INTO E PAC NEAR 07N98W.  MODERATE TO STRONG SUBSIDENCE 
MAINTAINS DRY STABLE AIR AT MID AND UPPER LEVELS WITHIN 10 DEG 
EITHER SIDE OF TROUGH AXIS.

SECOND DEEP LAYER CYCLONE APPROACHES COAST OF SOUTHERN 
CALIFORNIA TUE FOLLOWING SIMILAR PATH OF AFOREMENTIONED CYCLONE 
BUT AT SLIGHTLY MORE NORTHERN LATITUDE WHICH MAY LESSEN ITS 
IMPACT OVER E PAC BASIN WITHIN FORECAST PERIOD. 

ELSEWHERE AT THE LOW LEVELS...
HEALTHY HIGH PRES CENTER 1034 MB N OF AREA AT 34N138W COVER E 
PAC N OF ITCZ W OF 103W BRINGING STEADY FLOW OF E-NE FRESH 
BREEZE TRADES W OF 120W THROUGH FORECAST PERIOD.  LONG PERIOD NW 
SWELLS UP TO 10-11 FT PRODUCED BY DISSIPATED COLD FRONT SPREAD S 
TO 10N THROUGH TUE.  

GAP WINDS...
PREVIOUS GALE FORCE WINDS HAVE NOW DIMINISHED BUT LIKELY REMAIN 
AS FRESH N BREEZE THROUGH NEXT 6 HRS AS ITS SOURCE AIR MASS 
SHIFT EASTWARD.

GULF OF PAPAGAYO STRONG NE BREEZE CONTINUES UNABATED AS ATLC 
HIGH PRES NE OF AREA CONTINUES TO FORCE STRONG TRADES ACROSS 
ENTIRE CARIBBEAN.  WINDS FUNNEL ACROSS NICARAGUA MOUNTAIN PASSES 
AND EMERGE ON E PAC FROM 09N TO 11N.
 
$$
WALLY BARNES