000
AXPZ20 KNHC 122123
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU FEB 12 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 
2100 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 06N77W TO 03N90W TO 00N110W TO 
04N140W. SCATTERED MODERATE CONVECTION IS WITHIN 240 NM S OF THE 
AXIS E OF 82W AND WITHIN 240 NM N OF THE AXIS W OF 137W. 

...DISCUSSION...

THE PRESSURE GRADIENT BETWEEN A 1038 MB SFC HIGH NW OF THE AREA 
NEAR 36N146W AND LOWER PRES ALONG THE ITCZ IS PRODUCING A LARGE 
SWATH OF 20-25 KT TRADES FROM 07N-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 BEGINNING 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 137W 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...A SHIP RECENTLY REPORTED 35 KT OVER THE 
GULF...BUT WITH THE LACK OF ANY OTHER DATA AND BECAUSE THE SFC 
FRONT IS STALLED NEAR OR JUST W OF THE GAP THIS OBSERVATION 
APPEARS HIGH...SO KEPT 20-25 KT AS AN ESTIMATION. REGARDLESS... 
WINDS WILL BE DIMINISHING SHORTLY AS THE FRONT LIFTS BACK N AND 
HIGH PRES SHIFTS E.

$$
CANGIALOSI