000
AXPZ20 KNHC 130311
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI FEB 13 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...
ITCZ AXIS IS CENTERED ALONG 07N74W TO 03N90W TO 01N110W TO 
05N140W. SCATTERED MODERATE CONVECTION IS WITHIN 240 NM N OF THE 
AXIS W OF 135W.

...DISCUSSION...

THE PRESSURE GRADIENT BETWEEN A 1037 MB SFC HIGH NW OF THE AREA 
NEAR 36N147W AND LOWER PRES ALONG THE ITCZ IS PRODUCING A LARGE 
SWATH OF 20-25 KT TRADES FROM 08N-27N W OF 122W.  SIMILAR 
MAGNITUDE NLY WINDS ARE OBSERVED OFF THE N AND CENTRAL BAJA 
COAST. LITTLE CHANGE IN THE LARGE SCALE PRES/WIND PATTERN IS 
EXPECTED OVER THE NEXT DAY OR TWO.  HOWEVER...BY LATE SAT AND 
SUN AN AMPLIFIED LONGWAVE TROUGH WILL SHIFT E SUPPORTING A COLD 
FRONT THAT WILL ENTER THE N PORTIONS OF THE AREA INCREASING SW 
TO W WINDS AND SEAS. IN THE MEANTIME...LONG PERIOD NW SWELL 
COMBINED WITH WIND GENERATED WAVES WILL KEEP SEAS ELEVATED OVER 
8 FT ACROSS MUCH OF THE AREA W OF 100W-110W.  

THE MID AND UPPER LEVEL PATTERN IS FAIRLY BENIGN WITH WV IMAGERY 
AND DERIVED WINDS INDICATING FAIRLY UNIFORM W TO SW FLOW OVER 
MUCH OF THE ZONE. UPPER DIFFLUENCE IS ENHANCING CONVECTION 
WITHIN THE ITCZ W OF 135W AND THE DEBRIS CLOUDINESS IS BEING 
DRIVEN BY THE UPPER WINDS. THE PATTERN WILL BECOME MORE 
AMPLIFIED THIS WEEKEND AS MENTIONED ABOVE.   

GAP WINDS...
GULF OF PAPAGAYO...STRONG NE TO E TRADES OVER THE CARIBBEAN 
CONTINUE TO PROVIDE A TRAJECTORY THROUGH THE GULF OF PAPAGAYO. 
EARLIER SCATTEROMETER DATA AND A COUPLE OF SHIP OBS REVEAL 20-25 
KT FLOW OVER THE GAP. THIS WEATHER PATTERN IS EXPECTED TO 
PERSIST OVER THE NEXT COUPLE OF DAYS.

GULF OF TEHUANTEPEC...WINDS APPEAR TO HAVE DIMINISHED AS THE 
FRONT OVER THE GULF OF MEXICO IS LIFTING N AND HIGH PRES IS 
SHIFTING E OVER THE SOUTHEAST CONUS.

$$
CANGIALOSI