000
AXPZ20 KNHC 072141
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED JAN 07 2009

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...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...07N77W TO 
05N90W TO 07N110W TO 09N128W TO 06N140W. SCATTERED MODERATE 05N 
TO 08N BETWEEN 78W AND 81W...FROM 09N TO 11N BETWEEN 121W AND 
124W...AND FROM 04N TO 06N BETWEEN 136W AND 140W.

...DISCUSSION...

TRADES...
AN AMPLIFIED AND PROGRESSIVE UPPER PATTERN IS FORECAST TO 
CONTINUE THIS WEEK. A PAIR OF UPPER RIDGES AND AN UPPER TROUGH 
WILL TRANSLATE EASTWARD OVER THE CENTRAL PACIFIC THROUGH THIS 
WEEKEND. ALSO...AN UPPER LOW CENTERED NEAR 20N120W IS FORECAST 
TO DRIFT NW DURING THE NEXT COUPLE DAYS. AT THE SURFACE...A 1029 
MB SURFACE HIGH IS CENTERED JUST N OF THE AREA NEAR 31N135W. NE 
TRADE WINDS OF 20 TO 25 KT ARE AFFECTING AREAS S OF THE SURFACE 
HIGH. THESE WINDS EXTEND S TO THE ITCZ AND ARE ENHANCING THE 
NORTHERN PERIPHERY OF A SURFACE TROUGH FROM 12N128W TO 06N129W. 
THIS TROUGH IS FORECAST TO DRIFT WESTWARD DURING THE NEXT COUPLE 
DAYS. THE SURFACE HIGH IS FORECAST TO WEAKEN DURING THE NEXT 
COUPLE OF DAYS AS THE REMNANTS OF A COLD FRONT APPROACHES FROM 
NORTHERN EXTENT OF AREA. CORRESPONDINGLY...THE TRADE WINDS WILL 
RELAX THROUGH LATE WEEK...THOUGH THE REMNANTS OF THE FRONT WILL 
BE FOLLOWED BY NE WINDS TO 20 KT. THE TRADE WINDS ARE EXPECTED 
TO RESULT IN SEA HEIGHTS OF 8 TO 11 FT THROUGH LATE WEEK...WITH 
SIMILAR WAVE HEIGHTS IN NORTHWESTERLY SWELL IN THE WAKE OF THE 
FRONT.

GULF OF PAPAGAYO...
THE WEAK TRADE WIND FLOW OUT OF THE CARIBBEAN REGION HAS 
RESULTED IN A TEMPORARY LULL IN THE WINDS ACROSS THE GULF OF 
PAPAGAYO. HOWEVER...BY THURSDAY MORNING...THE INCREASING 
CARIBBEAN TRADES WILL RESULT IN 20 KT WINDS FUNNELING INTO THE 
GULF OF PAPAGAYO. THESE WINDS WILL BE ENHANCED BY DOWNSLOPE FLOW 
AT NIGHT OVER THE HIGHER TERRAIN OF COSTA RICA.

GULF OF CALIFORNIA...
NORTHERLY FLOW E OF THE 1029 MB SURFACE HIGH 900 NM W OF 
NORTHERN BAJA CALIFORNIA IS RESULTING IN N TO NW WINDS OF 20 KT 
ACROSS PORTIONS OF THE GULF OF CALIFORNIA. THESE WINDS ARE 
FORECAST TO CONTINUE FOR THE NEXT 24 HOURS. A HIGHLY AMPLIFIED 
UPPER RIDGE IS FORECAST LATER THIS WEEKEND TO BUILD OVER THE E 
PACIFIC AND W CONUS... WITH A STRONG SURFACE RIDGE EXTENDING 
FROM THE GREAT BASIN TO THE NORTHERN ROCKIES. NUMERICAL MODEL 
GUIDANCE SUGGESTS THAT A 1047 MB SURFACE HIGH WILL SET UP OVER 
WESTERN WYOMING BY SATURDAY. THIS PATTERN WILL BE PARTICULARLY 
FAVORABLE FOR THE DEVELOPMENT OF NORTHWESTERLY GALES THROUGH THE 
GULF OF CALIFORNIA THIS WEEKEND.

$$
FORMOSA