000
AXPZ20 KNHC 150307
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI DEC 15 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N78W 6N100W 5N120W 6N130W 
5N140W. SCATTERED MODERATE FROM 4N TO 7N BETWEEN 101W AND 104W. 
SIMILAR CONVECTION IS ALONG THE PACIFIC COAST OF COSTA RICA.

...DISCUSSION...
MID/UPPER LEVEL TROUGH EXTENDS FROM SOUTHERN TEXAS AND NE MEXICO 
ACROSS THE SOUTHERN BAJA PENINSULA NEAR 24N110W TO 18N137W. DRY 
AIR RESULTING IN MODERATE TO STRONG SUBSIDENCE IS BEHIND THE 
TROUGH. A SUBTROPICAL JET PERSIST BETWEEN THE TROUGH AND A RIDGE 
AXIS ALONG 11N. THE GFS MODEL 250 MB SHOWS THAT CORE SPEEDS ARE 
BETWEEN 70 AND 90 KT...PARTICULARLY EAST OF 125W. A STRONGER 
UPPER TROUGH AND ITS ASSOCIATED COLD FRONT ARE FORECAST TO MOVE 
INTO THE AREA LATE FRIDAY. 

AT THE SURFACE...
A 1029 MB SFC HIGH SITUATED NEAR 29N136W REMAINS IN CONTROL OF 
THE WEATHER PATTERN ACROSS THE AREA NORTH OF 15N WEST OF 110W. 
TIGHT PRESSURE GRADIENT BETWEEN THIS SFC HIGH AND A WEAK TROUGH 
ALONG THE ITCZ NEAR 131W IS GENERATING 20 TO 25 KT TRADE WINDS 
AND FAIRLY HIGH SEAS OVER THE AREA...IN MIXED NW AND NE SWELL. 
FURTHER E ANOTHER TROUGH IS EVIDENT NEAR 95W ALONG THE ITCZ. A 
SWIRL OF LOW CLOUDS WITH ISOLATED SHOWERS IS JUST BEHIND THE 
TROUGH AXIS. A STRONG COLD FRONT NW OF THE AREA WILL MOVE INTO 
THE REGION THIS WEEKEND...BRINGING A NOTICEABLE INCREASE IN 
WINDS AND SEAS TO MUCH OF THE AREA W OF 120W. THE NWW3 MODEL 
FORECASTS SEAS IN THE 12 TO 16 FT RANGE. WINDS ARE EXPECTED TO 
REACH NEAR GALE FORCE.  

GAP WINDS...
WINDS OF 20 TO 25 KT AND SEAS TO 8 KT WILL PERSIST IN THE GULF 
OF TEHUANTEPEC THROUGH 48 HOURS. 

$$
GR