000
AXPZ20 KNHC 132156
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI MAR 13 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 
2115 UTC.

...ITCZ...
AXIS ALONG 08N83W TO 01N108W TO 06N131W TO 06N140W.  ISOLATED 
MODERATE WITHIN 45 NM OF AXIS E OF 90W AND FROM 126W-129W. 

...DISCUSSION...
UPPER LEVEL ANTICYCLONE WITH RIDGE AXIS ALONG 126W HAS FLATTENED 
CREST N OF 29N BY SHORTWAVE TROUGH APPROACHING SRN CALIFORNIA.  
RIDGE IS ONLY OBSTACLE BLOCKING UPPER LEVEL CUTOFF CYCLONE FROM 
MOVING E OVER FORECAST WATERS.  DEEP LAYER CYCLONE HAS SURFACE 
LOW PRES 1000 MB AT 27N155W WITH STORM FORCE WINDS JUST OUTSIDE 
E PAC BOUNDARY...AND 20-30 KT GUSTY WINDS OVER NW CORNER OF 
FORECAST WATERS.  MODEL GUIDANCE HAS REINFORCED RIDGE HOLDING 
ITS GROUND WITH LOW PRES SPINNING W OF AREA BEYOND FORECAST 
PERIOD BEFORE ATTEMPTING A FINAL NE MOVE WHEN RIDGE FINALLY 
WEAKENS.  RIDGE BEGINNING TO COLLAPSE SE AS NEW SHORTWAVE TROUGH 
DIGS SE INTO DISCUSSION AREA.  MEANWHILE CYCLONE ADVECTING 
ENORMOUS AMOUNTS OF TROPICAL MOISTURE INTO E PAC WHERE RIDGE 
THEN CARRIES ALONG ITS FLATTENED CREST ACROSS SRN HALF OF BAJA 
CALIFORNIA AND NRN MEXICO INTO SE TEXAS AND NW GULF OF MEXICO 
WHERE COLD FRONT USES FOR DEEP CONVECTION.  

ELSEWHERE OVER FORECAST WATERS UPPER RIDGE AND SURFACE 
COUNTERPART MAINTAIN DRY AIR MASS WITH ONLY ISOLATED MINOR 
CONVECTION ALONG ITCZ.

ELSEWHERE AT THE SURFACE...
MAIN SURFACE FEATURE IS AFOREMENTIONED LOW PRES 1000 MB 
PRODUCING VERY STRONG WINDS NEAR NW CORNER OF BASIN AND LARGE 
LONG PERIOD SWELL PROPAGATING NE ACROSS EQUATOR.  S SWELL 
EVENTUALLY DOMINATE MOST OF E PAC S OF 20N WITHIN 24 HRS AND 
REACH 30N BY END OF FORECAST PERIOD.  
 
NE WINDS CONTINUE TO BRIDGE ACROSS GULF OF PAPAGAYO WITH LITTLE 
CHANGE THROUGH NEXT 48 HRS.  GULF OF PANAMA EXPECTED TO DIMINISH 
BELOW 20 KT TONIGHT.   

$$
WALLY BARNES