000
AXPZ20 KNHC 071635
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU DEC 07 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 
1615 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG...4N78W 6N90W 5N100W 6N110W 7N120W
8N130W 8N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 
60 NM EITHER SIDE OF THE AXIS BETWEEN 117W-120W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 7N-10N BETWEEN
120W-128W...AND ALSO WITHIN 30 NM EITHER SIDE OF THE AXIS BETWEEN
130W-134W.

...DISCUSSION...

MIDDLE AND UPPER LEVEL TROUGH EXTENDS SOUTH-SOUTHWEST FROM 
ARIZONA TO ACROSS BAJA CALIFORNIA AND SOUTHWEST TO 21N117W.
WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE AND ASSOCIATED
DRY AIR ADVECTING EASTWARD NORTH OF 20N EAST OF 125W. MID/UPPER
LEVEL RIDGING COVERS THE AREA BEHIND THE TROUGH AND OVER MUCH 
OF THE REGION NORTH OF 9N WITH AN ASSOCIATED MID/UPPER LEVEL
ANTICYCLONIC CIRCULATION NEAR 11N118W. A RIDGE EXTENDS EAST/WEST
FROM THIS CIRCULATION CENTER TO BETWEEN 100W AND 135W. ANOTHER 
MID AND UPPER LEVEL TROUGH IS OVER THE EXTREME NORTHWEST PORTION 
OF THE REGION NORTH OF 25N WEST OF 138W WITH MEAN TROUGH AXIS 
NORTH OF 25N ALONG 25N. AT THE SURFACE...A COLD FRONT HAS ENTERED
THE EXTREME NORTHWEST CORNER OF THE AREA. STRONG NORTHWEST WINDS
IN THE RANGE OF 25-30 KT WITH HIGHER GUSTS WILL FOLLOW THE FRONT
BEGINNING IN THE NEXT 12 HOURS AND CONTINUING THROUGH THE NEXT
48 HOURS. MAIN PROBLEM AFFECTING THE REGION WITH RESPECT TO THIS
FRONT ARE THE LARGE NW-N SWELLS THAT WILL BE SPREADING THROUGHOUT
MUCH OF THE WESTERN AND CENTRAL SECTIONS OVER THE NEXT FEW DAYS
AS THE FRONT WEAKENS AND EVENTUALLY DISSIPATES. WAVEWATCH MODEL 
SUGGESTS MAXIMUM HEIGHTS OF UP TO 24 FT POSSIBLY MOVING INTO THE 
NORTHWEST PART OF THE AREA IN THE WAKE OF THE FRONT. A NEW
COLD FRONT BRUSHES THE NORTHERN SECTION OF THE REGION FROM
FRIDAY EVENING THROUGH SUNDAY BEFORE QUICKLY WEAKENING AS IT
MOVES INTO SOUTHERN CALIFORNIA AND NORTHERN BAJA CALIFORNIA.

A MID/UPPER LEVEL CYCLONIC CIRCULATION MOVING NORTH-NORTHEAST 
ABOUT 15-20 KT IS LOCATED NEAR 18N140W. ABUNDANT MID/UPPER LEVEL 
MOISTURE IN THE FORM OF BROKEN TO SCATTERED HIGH CLOUDS 
STREAMING EAST-NORTHEAST COVER THE AREA TO THE EAST AND SOUTH OF 
BOTH TROUGHS SOUTH TO 8N. OVERCAST HIGH LEVEL CLOUDINESS IS 
STREAMING EASTWARD NORTH OF 19N EAST OF 113W TO ACROSS NORTHWEST 
MEXICO...WITH THE EXCEPTION OF THIN HIGH LEVEL CLOUDS FROM 
10N-18N BETWEEN 100W-125W. SATELLITE WATER VAPOR IMAGERY 
INDICATES MODERATE TO STRONG SUBSIDENCE AND ASSOCIATED DRY AIR 
PRESENT S OF 14N EAST OF 112W WITH VERY LIMITED SHOWER AND 
THUNDERSTORM FOUND IN THIS AREA.

GAP WINDS...
NE WINDS IN THE 20-30 KT RANGE OVER THE GULF OF TEHUANTEPEC AS
OBSERVED IN A MORNING QUIKSCAT PASS ARE EXPECTED TO INCREASE ONCE
AGAIN TO GALE FORCE IN 36 HOURS AS THE GRADIENT OVER MEXICO 
TIGHTENS. SEAS IN THE GULF OF TEHUANTEPEC CURRENTLY TOPPING UP 
TO 13 FT WILL CHANGE LITTLE THROUGH THE NEXT 36 HOURS THEN 
INCREASE SLIGHTLY ONCE THE EVENT BEGINS. THIS NEXT GALE EVENT IS 
EXPECTED TO CONTINUE TO POSSIBLY INTO SUN AFTERNOON.

NE WINDS OF 20 KT ACROSS THE GULF OF PAPAGAYO ARE EXPECTED TO 
DIMINISH TO LESS THAN 20 KT WITHIN THE NEXT 18 HOURS.

$$
AGUIRRE