000
AXPZ20 KNHC 071550
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED JAN 07 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...07N77W TO 
06N88W TO 08N102W TO 06N119W TO 07N131W TO 06N140W. SCATTERED 
MODERATE CONVECTION WITHIN 90 NM OF 07N83W...WITHIN 60 NM OF 
06N137W...WITHIN 60 NM OF 07N125W...AND WITHIN 60 NM OF 07N80W.

...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 19N123W IS FORECAST 
TO DRIFT WESTWARD DURING THE NEXT COUPLE DAYS. AT THE 
SURFACE...A 1033 MB SURFACE HIGH IS CENTERED IN THE CENTRAL 
PACIFIC NEAR 34N134W. NE TRADE WINDS OF 20 TO 25 KT ARE 
AFFECTING AREAS S OF THE SURFACE HIGH. THESE WINDS ARE ENHANCED 
AROUND THE NORTHERN PERIPHERY OF A SURFACE TROUGH EMBEDDED 
WITHIN THE ITCZ EXTENDING FROM 12N125W TO 06N126W. THIS TROUGH 
IS FORECAST TO DRIFT WESTWARD DURING THE NEXT COUPLE DAYS...AS 
IT BECOMES IN PHASE WITH THE AFOREMENTIONED UPPER LOW. ALSO... 
WITH THE PROGRESSIVE UPPER PATTERN IN PLACE...THE HIGH IS 
FORECAST TO WEAKEN DURING THE NEXT COUPLE OF DAYS AS THE 
REMNANTS OF A COLD FRONT APPROACH FROM THE CENTRAL PACIFIC. 
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 ARRIVING FROM THE CENTRAL PACIFIC 
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 1030 MB SURFACE HIGH OVER THE CENTRAL 
PACIFIC IS RESULTING IN N TO NW WINDS OF 20 KT ACROSS PORTIONS 
OF THE GULF OF CALIFORNIA. THESE WINDS ARE FORECAST TO CONTINUE 
DURING THE NEXT DAY. A HIGHLY AMPLIFIED UPPER RIDGE IS THEN 
FORECAST TO BUILD OVER THE E PACIFIC AND W CONUS THIS WEEKEND... 
WITH A STRONG SURFACE RIDGE EXTENDING FROM THE GREAT BASIN TO 
THE NORTHERN ROCKIES. IN FACT...NUMERICAL MODEL GUIDANCE 
SUGGESTS THAT A 1047 MB SURFACE HIGH COULD 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.

$$
COHEN/CHRISTENSEN