000
AXPZ20 KNHC 201517
TWDEP 

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

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH 7N81W 7N93W. ITCZ 7N93W 9N110W 7N120W 8N140W. 
SCATTERED MODERATE TO STRONG CONVECTION WITHIN 60 NM EITHER SIDE 
OF AXIS FROM 108W-120W AND WITHIN 90 NM N OF AXIS FROM 123W-129W.

...DISCUSSION...
UPPER LEVEL RIDGE WITH AXIS FROM AN ANTICYCLONIC CIRCULATION 
CENTERED NEAR 11N100W TO 18N130W TO 32N140W. UPPER LEVEL 
DIFFLUENT FLOW S OF THE RIDGE AXIS IS ENHANCING CONVECTION ALONG 
THE ITCZ FROM 108W-129W. A 105-120 KT JETSTREAM ALONG THE 
NORTHERN PERIPHERY OF THE RIDGE...BETWEEN THE RIDGE AND AN UPPER 
LEVEL TROUGH OVER THE SW U.S. INTO NORTHERN BAJA CALIFORNIA  
EXTENDS FROM 29N129W ACROSS THE CENTRAL BAJA PENINSULA INTO 
NORTHERN MEXICO. HIGH LEVEL MOISTURE IS MOVING THROUGH THE NW 
PORTION OF THE RIDGE W OF 135W. UPPER LEVEL TROUGH EXTENDS FROM 
THE YUCATAN PENINSULA THROUGH GUATEMALA TO 8N91W. MODERATE TO 
STRONG SUBSIDENCE WITH DRY STABLE AIR AT THE MIDDLE AND UPPER 
LEVELS IS N OF THE ITCZ TO 22N E OF 115W.

A WEAK 1014 MB LOW PRES IS CENTERED NEAR 32N118W WITH A TROUGH 
FROM THE LOW TO 27N125W 28N133W. OTHERWISE SURFACE RIDGE COVERS 
THE AREA N OF 18N W OF 115W. ELY WIND TO 20 KT ARE ALONG THE 
SOUTHERN PORTION OF THE RIDGE FROM 10N-20N W OF 110W WITH LARGE 
NW SWELLS...TO 12 FT...PROPAGATING THROUGH THE AREA N OF 10N W 
OF 11OW. SURFACE TROUGH ANALYZED ALONG THE ITCZ WITH AXIS FROM
13N134W TO 8N137W. MODERATE TO STRONG CONVECTION WITH THE TROUGH 
IS FROM 10N-13N BETWEEN 133W AND 138W.

$$
DGS