000
AXPZ20 KNHC 120409
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU MAR 12 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
AXIS ALONG 08N82W TO 00N105W TO 03N128W TO 03N140W.
NO SIGNIFICANT CONVECTION.

...DISCUSSION...
WELL DEFINED SHORTWAVE AT 33N122W ROUNDS BASE OF LONG WAVE TROUGH
ALONG 121W FLATTENING CREST OF MID-UPPER LEVEL RIDGE ALONG 125W. 
WINDS ALOFT BECOME QUASI-ZONAL WIT LARGE MOISTURE PLUME COVERING 
BASIN N OF 15N.  RIDGE MAINTAINS AREA S OF 15N E OF 130W VERY 
DRY UNDER MODERATE TO STRONG SUBSIDENCE CURTAILING CONVECTION 
EVEN INCLUDING ITCZ.  ADVECTED MOISTURE REACHING CENTRAL TEXAS 
FEEDING DEVELOPING LOW PRES AND ASSOCIATED COLD FRONT THERE. 

W OF NW CORNER OF E PAC...VERY STRONG LARGE AMPLITUDE TROUGH 
RAPIDLY APPROACHING 140W WITH LIKELIHOOD OF CUT OFF CYCLONIC 
VORTEX FORMING NEAR 30N144W WITHIN NEXT TWO DAYS.  THIS SHOULD 
REFLECT AT THE SURFACE AS INTENSE LOW PRES WHICH MODEL GUIDANCE 
INDICATE WILL CARRY STORM FORCE WINDS NEAR BASIN BOUNDARIES... 
NOT EXPECTED OVER FORECAST WATERS...BUT TOO CLOSE FOR COMFORT.   

AT THE SURFACE...RAPIDLY WEAKENING HIGH PRES CENTER N OF BASIN 
MOVED FURTHER NE ALLOWING FAST MOVING UPSTREAM TROUGH TO MOVE E 
DIMINISHING TRADE WINDS W OF 130W FROM 15N-23N.  IN ITS LIEU SE 
WINDS INCREASE THU N OF 20N W OF 135W IN RESPONSE TO DEVELOPING 
LOW PRES AT NW CORNER OF E PAC.  LARGE LONG PERIOD SWELLS CAUSED 
BY HIGH PRES CENTER HAVE BEEN AFFECTING WRN SIDE OF E PAC FOR 
OVER A WEEK SHOULD SUBSIDE...BUT NEW DEVELOPING STORM MENTIONED 
ABOVE SHOULD REBUILD SEAS OVER 15 FT.  

GAP WINDS ACROSS GULFS OF PAPAGAYO AND PANAMA CONTINUE TO 
DIMINISH AS LOW PRES 1008 MB OVER COLOMBIA WEAKENS WITHIN NEXT 
TWO DAYS.

$$
WALLY BARNES