000
AXPZ20 KNHC 222123
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON DEC 22 2008

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...
ITCZ IS CENTERED ALONG 5N77W 8N90W 6N95W 8N120W 7N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 180 NM N OF 
AXIS FROM 119W-130W.


...DISCUSSION...
DEEP LAYERED CUT OFF LOW CENTERED NEAR 19N139W. ASSOCIATED 
INVERTED SURFACE TROUGH IS A FEW DEGREES TO THE E OF THIS DEEP 
LAYERED LOW EXTENDING FROM 10N-20N ALONG 134W. LOW-LEVEL 
CONVERGENCE COMBINED WITH INSTABILITY AND DIFFLUENCE ALOFT IS 
MAINTAINING A LARGE AREA OF SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION FROM 13N-24N BETWEEN 126W-136W. 

BROAD MID/UPPER LEVEL TROUGH OVER THE N PORTION OF THE 
DISCUSSION AREA IS ALONG THE W COAST OF THE U.S. WITH AXIS 
32N121W TO 23N125W. A 90-95 KT JET STREAM EXTENDS FROM 28N125W
ACROSS CENTRAL BAJA CALIFORNIA INTO NORTHERN MEXICO. WEAK UPPER 
LEVEL RIDGE WITH AXIS FROM CENTRAL MEXICO NEAR 25N100W TO 8N110W.
UPPER LEVEL TROUGH EXTENDS FROM THE YUCATAN PENINSULA ACROSS THE 
GULF OF TEHUANTEPEC TO THE EQUATOR AT 83W. A LARGE AREA OF 
SUBSIDENCE WITH DRY STABLE AIR AT THE MIDDLE AND UPPER LEVELS OF 
THE ATMOSPHERE COVERS THE AREA S OF 20N E OF 110W.

A COLD FRONT ENTERS THE AREA AT 32N119W TO 30N128W THEN NW TO
32N136W. NO SIGNIFICANT WEATHER ASSOCIATED WITH THE FRONT. A 
SURFACE TROUGH ANALYZED ALONG THE ITCZ FROM 8N-11N ALONG 105W.
SCATTERED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF TROUGH.
HIGH PRES BUILDING N OF A FRONT IN THE GULF OF MEXICO HAS 
TIGHTENED THE GRADIENT OVER SOUTHERN MEXICO WITH GALE FORCE 
WINDS BLOWING THROUGH THE GULF OF TEHUANTEPEC. THE WINDS WILL 
DECREASE BELOW GALE FORCE LATER TONIGHT.

$$
DGS