000
AXPZ20 KNHC 130342
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 08N83W TO 02N102W TO 05N140W.  
ISOLATED MODERATE WITHIN 30 NM OF AXIS FROM 88W-92W.

...DISCUSSION...
WELL DEFINED SHORTWAVE AT 31N112W ROUNDS BASE OF LONG WAVE 
TROUGH ALONG 114W FLATTENING CREST OF MID-UPPER LEVEL RIDGE 
ALONG 118W.  WINDS ALOFT BECOME QUASI-ZONAL WITH LARGE MOISTURE 
PLUME COVERING BASIN N OF 12N W OF 120W AND N OF 15N FROM 112W 
TO 120W.  RIDGE MAINTAINS AREA S OF 12N E OF 130W VERY DRY UNDER 
MODERATE TO STRONG SUBSIDENCE CURTAILING CONVECTION EVEN 
INCLUDING ITCZ.  ADVECTED MOISTURE REACHING CENTRAL TEXAS 
FEEDING DEVELOPING COLD FRONT IN GULF OF MEXICO. 

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 AND FRI 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 18 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