000
AXPZ20 KNHC 121502
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON DEC 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON 
TROUGH 9N84W 6N95W. ITCZ AXIS FROM 6N95W 09N125W 7N140W. 
SCATTERED MODERATE TO STRONG CONVECTION WITHIN 90 NM S OF AXIS 
FROM 125W-137W.

...DISCUSSION...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 12N137W 
WITH A RIDGE EXTENDING FROM THE ANTICYCLONE N TO 32N138W. A DEEP 
LAYERED TROUGH ALONG THE WEST COAST WITH A 95-100 KT JETSTREAM 
ALONG THE SOUTHERN BASE OF THE TROUGH FROM 26N133W THEN WINDS
INCREASES TO 115-125 KT FROM 24N125W TO CENTRAL BAJA CALIFORNIA 
INTO NW MEXICO. ABUNDANT MOISTURE IS STREAMING NORTHEASTWARD 
WITHIN 300 NM SE OF THE JET AXIS. AN UPPER LEVEL ANTICYCLONIC 
CIRCULATION SE TO THE UPPER TROUGH IS CENTERED NEAR 14N110W WITH 
RIDGE NE INTO CENTRAL MEXICO. STRONG SUBSIDENCE WITH DRY STABLE 
AIR AT THE MIDDLE AND UPPER LEVELS COVERS THE AREA S OF 20N E OF 
120W. 

TIGHT PRES GRADIENT ACROSS SOUTHERN MEXICO IS PRODUCING STRONG 
NLY WINDS TO 30 KT THROUGH THE GULF OF TEHUANTEPEC. THESE WINDS 
ARE EXPECTED TO CONTINUE THROUGH WED.

SURFACE RIDGE EXTENDS FROM NEAR 32N138W SE TO 22N124W. 
COMBINATION OF RIDGE WITH ITCZ ASSOCIATED LOW PRES IS SUSTAINING 
E-NE WINDS 20 KT FROM 09N TO 22N W OF 130W WITH 9-10 FT SEAS.
STRONG NLY WINDS IN THE 20-30 KT RANGE WITH SEAS 9-11 FT N OF 
25N BETWEEN 120W-135W. THESE WINDS ARE FORECAST TO DECREASE TO 
LESS THAN 20 KT WED...HOWEVER LARGE NLY SWELLS WILL CONTINUE.

$$
DGS