000
AXPZ20 KNHC 221616
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI DEC 22 2006

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 
1515 UTC.

...ITCZ...
THE ITCZ AXIS IS ALONG 4N77W 7N85W 6N100W 6N110W 
8N120W 6N130W 7N140W.  ISOLATED MODERATE CONVECTION IS S OF 
PANAMA FROM 4N TO 8N BETWEEN 77W AND 80W.  SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS FROM 4N TO 8N BETWEEN 128W AND 
140W. 

...DISCUSSION...
UPPER LEVELS...AN UPPER RIDGE IS OVER THE FAR NW PORTION OF THE 
AREA N OF 20N BETWEEN 120W AND 140W WHILE A CUTOFF UPPER LOW IS 
OVER S CALIFORNIA NEAR 35N115W.  AN UPPER HIGH JUST S OF 
GUATEMALA IS AFFECTING MUCH OF THE AREA BETWEEN 85W AND 110W.  A 
JETSTREAM WITH AXIS ALONG 13N110W 21N97W IS ADVECTING 
SIGNIFICANT MOISTURE ACROSS MEXICO AND INTO THE GULF OF MEXICO.  
EXTENSIVE DRY AND STABLE AIR DOMINATES FROM 15N-25N W OF 110W 
AND OVER THE FAR NE PACIFIC E OF 105W. 

SURFACE FEATURES...A 1028 MB SURFACE HIGH IS NEAR 29N130W AND 
EXPECTED TO DRIFT NE OVER THE NEXT COUPLE DAYS.  FRESH 
TRADEWINDS ASSOCIATED WITH THIS FEATURE PERSIST FROM 10N-20N 
MAINLY WEST OF 120W. ONLY SLIGHT WEAKENING ANTICIPATED IN THESE 
WINDS THROUGH SUN. THE ASSOCIATED SHORT PERIOD WIND WAVES WILL 
MIX WITH THE LARGE...LONG PERIOD NW SWELL SPREADING THROUGH THE 
AREA THROUGH THE WEEKEND. NW WINDS ARE RELAXING IN THE GULF OF 
CALIFORNIA BUT THIS WILL ONLY BE TEMPORARY. BOTH NAM/GFS 
SUGGESTING 20 TO 30 KT NW WINDS WILL INCREASE BY SAT IN RESPONSE 
TO STRONG HIGH PRESSURE BUILDING N OF THE AREA AND INTERACTING 
WITH THE INVERTED TROUGH OVER THE AREA. ASSOCIATED STEEP NNW 
WIND WAVES WILL AGAIN BE LARGEST S OF 26N AT THE TAIL END OF THE 
FETCH.  IN THE TROPICS...THE ITCZ BECAME ACTIVE TODAY W OF 128W 
SEE ABOVE.  
 
GAP WINDS...
NO SIGNIFICANT GAP FLOW WINDS ARE OCCURRING NOW OR OVER THE NEXT 
TWO DAYS AT TEHUANTEPEC OR PAPAGAYO.  HOWEVER...BY SUNDAY 
EVENING...A STRONG COLD FRONT PUSHING ACROSS THE GULF OF MEXICO 
WILL INITIATE A TEHUANTEPEC WIND EVENT.

$$
FORMOSA