000
AXPZ20 KNHC 170916
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JAN 17 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0830 UTC.

...ITCZ...

ITCZ IS CENTERED ALONG 2N78W 5N93W 6N111W 8N126W 5N135W 6N140W. 
SCATTERED STRONG CONVECTION IS WITHIN 150 NM OF LINE 07N110W TO 
16N113W. 

...DISCUSSION...
DEEP LAYER LARGE AMPLITUDE UPPER LEVEL TROUGH DIGS S FROM 
30N132W TO 17N133W THEN SE TO AN UPPER LOW NEAR 15N124W. UPPER 
TROUGH UNABLE TO PROCEED E DUE TO BLOCKING UPPER LEVEL RIDGE 
THAT EXTENDS FROM 14N103W TO 27N127W. A SURFACE TROUGH EXTENDS 
FROM NEAR THE UPPER LOW TO THE ITCZ ALONG 125W FROM 6N TO 15N. 
AREA OF DIFFLUENT FLOW SW OF UPPER RIDGE IS ENHANCING CONVECTION 
ABOVE. AN UPPER LOW IS ALONG THE SW COAST OF CALIFORNIA COVERING 
THE AREA N OF 30N E OF 127W. RIDGE ANTICYCLONIC UPPER FLOW 
ADVECTS TROPICAL MOISTURE N AND NE ACROSS AREA TO OVER THE BAJA 
PENINSULA AND W MEXICO. 

GULF OF TEHUANTEPEC AND IMMEDIATE AREA SW OF IT CONTINUE UNDER 
STRONG GALE WARNING BUT WILL BEGIN TO WEAKEN AND BE BELOW GALE 
FORCE SUN AFTERNOON. 

GULF OF PAPAGAYO STRONG NE WINDS CONTINUE AND WILL WEAKEN AND 
DISSIPATE MON MORNING. 

STRONG COLD FRONT WILL ENTER THE NW CORNER OF THE AREA ON SUN 
MORNING THEN BEGIN TO WEAKEN ON MON AS THE UPPER SUPPORT 
COLLAPSES AND STALLS JUST W OF BLOCKING RIDGE. NEVERTHELESS...AN 
AREA OF HIGH SEAS 10 TO 18 FT COVER THE NW CORNER AHEAD OF THE 
FRONT AND WILL SPREAD SE TO COVER MOST OF THE AREA W OF 120W BY 
MON. 
 
WEAK RIDGE CURRENTLY COVERS THE AREA N OF 15N E OF 140W ANCHORED 
OVER THE NW U.S. 

$$
WALLACE