000
AXPZ20 KNHC 171534
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE FEB 17 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...
AXIS FROM 04N77W TO 01N95W TO 04N122W TO 01N140W.
NO SIGNIFICANT CONVECTION.

...DISCUSSION...
LARGE AMPLITUDE MID/UPPER LEVEL TROUGH OVER NW PORTION OF BASIN 
FROM 32N12W TO 17N140W.  VERY DRY AIR MASS WITHIN 300 NM W OF 
AXIS.  SW JET STREAM 100 KT RUNS SE OF AXIS ADVECTING ABUNDANT 
UPPER LEVEL TROPICAL MOISTURE INTO S HALF OF BAJA CALIFORNIA AND 
NW MEXICO...WHERE SURFACE RIDGE AXIS MAINTAIN CAP ON ANY 
DEVELOPING CONVECTION.  BROAD MID/UPPER LEVEL ANTICYCLONE 
CENTERED AT 07N94W HAS RIDGE EXTEND ALONG MEXICO BACKBONE INTO 
CENTRAL TEXAS SUPPORTING WELL ANCHORED PSN OF SURFACE RIDGE.
STRONG SUBSIDENCE ALOFT MAINTAIN VERY DRY AND STABLE AIR MASS 
ANYWHERE IN BASIN SE OF JET STREAM AXIS MENTIONED ABOVE... 
INCLUDING ALONG ITCZ.

AT THE SURFACE...
STRONG COLD FRONT EXTEND FROM 1015 MB LOW PRES AT 31N139W TO 
29N140W.  LOW PRES MOVES NE DRAGGING FRONT ALONG AND N OF 
FORECAST WATERS WITHIN 48 HRS.  STRONG 20-30 KT WINDS WITHIN 300 
NM E OF FRONT N OF 26N...WITH POSSIBLE OCCASIONAL GUST TO GALE 
FORCE AND 13-15 FT.  WINDS DIMINISH QUICKLY WITH FRONT NE SHIFT  
...BUT LARGE SWELLS SPREAD SE THROUGH ENTIRE FORECAST PERIOD.

GAP WINDS...
GULF OF TEHUANTEPEC STRONG N-NE WIND DIMINISH WITHIN NEXT 12 HRS 
AS HIGH PRES OVER GULF OF MEXICO FORCING WINDS ACROSS ISTHMUS 
MOVES SE SHIFTING WIND DIRECTION AWAY FROM TEHUANTEPEC.  STRONG  
CARIBBEAN TRADES ACROSS GULF OF PAPAGAYO EXPECTED TO EXTEND 
BEYOND FORECAST PERIOD AS HIGH PRES BRINGS TIGHTER PRES GRADIENT 
INTO NW CARIBBEAN.  GULF OF PANAMA N WINDS DWINDLE WITHIN NEXT 
48 HRS AS WINDS IN WRN CARIBBEAN BECOME MORE E-NE.

$$
WALLY BARNES