000
AXPZ20 KNHC 160347
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI DEC 16 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 AXIS FROM 09N85W TO 07N93W TO 06N98W THEN ITCZ TO 
08N127W TO 07N139W.  SCATTERED MODERATE CONVECTION WITHIN 120 NM 
OF AXIS E OF 104W.

...DISCUSSION...
DEEP LAYER LONG WAVE TROUGH FROM WESTERN TEXAS ACROSS NW MEXICO 
TO 08N122W DRIES OUT CENTRAL PORTIONS OF BASIN WHILE ANTICYCLONE 
AT 08N130W WITH CREST TO 32N132W ADVECTS PLENTY OF UPPER LEVEL 
MOISTURE INTO BASIN.  ON THE EASTERN THIRD OF BASIN...MID TO 
UPPER LEVEL RIDGE EXTENDS FROM SOUTH AMERICA ACROSS CENTRAL 
AMERICA AND ALSO BRINGS PLENTY OF MOISTURE INTO MONSOON TROUGH 
AXIS E OF 104W. 

STRONG SHORT WAVE TROUGH SLIDING INTO BASE OF LONGWAVE TROUGH 
BROUGHT WELL DEFINED UPPER LEVEL CYCLONE NOW AT 35N115W SWINGING 
INTO EXTREME NW MEXICO FRI AND SAT THEN MOVING OUT OF SCENE 
SUN.  CYCLONE SUPPORTS COLD FRONT BOUNDARY INTO NE PORTIONS OF 
BASIN WITH FRESH N WINDS AND SEAS TO 10-14 FT BEHIND FRONT 
TONIGHT AND FRI THEN SUBSIDE BY LATE SAT.

HIGH PRES CENTER 1032 MB N OF 30N KEEP TIGHT GRADIENT WITH ITCZ 
TO SUPPORT FRESH NE TRADE WINDS W OF 130W.  TRADE WIND COVERAGE 
SHRINK AS COLD FRONT ERODES HIGH PRES AND EASES GRADIENT BY SAT.

N WINDS ACROSS GULF OF TEHUANTEPEC FORECAST TO INCREASE LATE FRI 
NIGHT AND SAT TO STRONG AS NEW COLD FRONT CROSSES GULF OF MEXICO 
FORCING STRONG WINDS ACROSS CHIVELAS PASS IN THE ISTHMUS OF 
TEHUANTEPEC.  WINDS ALSO INCREASE IN GULF OF PAPAGAYO WITHIN 36 
HOURS BECOMING STRONG BY LATE SAT.


$$
WALLY BARNES