000
AXPZ20 KNHC 222143
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JAN 22 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 
2045 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG THE AXIS FROM 
04N77W TO 03N95W TO 07N113W TO 05N124W TO 05N140W. THERE IS NO 
SIGNIFICANT CONVECTION CURRENTLY ASSOCIATED WITH THE ITCZ.


...DISCUSSION...

THE ASCAT PASS FROM 1538 UTC CONFIRMS THE END OF THE GALE EVENT 
IN THE GULF OF TEHUANTEPEC...WITH THE HIGHEST RETURNS SHOWING 
WINDS ONLY TO 30 KT. THIS PASS ALSO HAD PARTIAL COVERAGE OF THE 
GULF OF PAPAGAYO WHERE WINDS ARE STILL SOLIDLY IN THE 20 TO 25 
KT RANGE.  WINDS HERE ARE EXPECTED TO DIMINISH SLIGHTLY OVER THE 
NEXT 24 TO 48 HOUR AS THE PRESSURE GRADIENT BETWEEN HIGH 
PRESSURE OVER CENTRAL AMERICA AND LOW PRESSURE OVER COLUMBIA 
SLACKENS.  LAST OBSERVATIONS OVER THE GULF OF FONSECA ALSO 
SHOWED WINDS IN THE 20 TO 25 KT RANGE...BUT WINDS ARE EXPECTED 
TO DIMINISH HERE MORE RAPIDLY THAN IN THE GULF OF PAPAGAYO AS 
THE WIND DIRECTION IN THE WESTERN CARIBBEAN BECOMES MORE 
EASTERLY AND LESS FAVORABLE FOR BLEEDING THROUGH THE GULF OF 
FONSECA.  UNFORTUNATELY...THERE HAS NOT BEEN A SCATTEROMETER 
PASS OVER THE GULF OF PANAMA SINCE 0302 UTC.  AT THAT 
TIME...WINDS WERE IN THE 20 TO 25 KT RANGE OVER A SMALL 
AREA...BUT IT IS SUSPECTED THAT THE WINDS HAVE DIMINISHED SINCE 
THAT TIME.  THERE IS ONE OBSERVATION...A8ME4 NEAR 07N80WB 
SHOWING 15 KT WINDS AT 1800 UTC...TO CONFIRM THIS.

THE COLD FRONT APPROACHING BAJA CALIFORNIA WILL BE LIFTED N OF 
THE AREA BY TOMORROW AFTERNOON AS THE DEEP LAYER LOW JUST N OF 
FAR WESTERN WATERS OVERTAKES THIS SYSTEM.  CONVECTION ASSOCIATED 
WITH THE DIFFLUENCE AREA ON THE LEADING EDGE OF THE UPPER TROUGH 
SUPPORTING THIS COLD FRONT IS ONLY GENERATING ISOLATED MODERATE 
CONVECTION WITHIN 210 NM W AND 270 NM E OF 108W FROM 08N TO 16N 
AT THE MOMENT WHILE BROKEN MID TO UPPER LEVEL CLOUDS ARE LIKELY 
BRINGING SOME STRATIFORM PRECIP TO THE BAJA AND PORTIONS OF NW 
MEXICO...WITH SOME ISOLATED EMBEDDED CONVECTION POSSIBLE.  THIS 
TROUGH IS EXPECTED TO BECOME MORE POSITIVELY TILTED...WITH THE 
LEADING EDGE OF THE UPPER TROUGH MOVING INTO NW MEXICO OVERNIGHT 
TONIGHT WHILE A WEAK UPPER LOW IS PINCHED OFF FARTHER SOUTH.  A 
WEAK SURFACE TROUGH...REFLECTING THE UPPER LOW...IS EXPECTED TO 
LINGER BETWEEN 116W AND 126W OVER THE NEXT DAY OR TWO.

THE DEEP LAYER LOW N OF THE FORECAST AREA WILL BE SLOW TO MOVE 
EASTWARD...AMPLIFYING OVER NW WATERS OVER THE NEXT FEW DAYS AS 
IT IS RELOADED WITH NORTHERN STREAM ENERGY.  THE ASSOCIATED COLD 
FRONT WILL ALSO BE SLOW MOVING. WINDS IN EXCESS OF 25 KT ARE 
EXPECTED TO REMAIN N OF FORECAST WATERS...BUT SEAS ARE EXPECTED 
TO BUILD TO THE 16 TO 18 FT RANGE WITH THIS SYSTEM.  LONG PERIOD 
SWELL...ON THE ORDER OF 15 TO 16 SECONDS...IS EXPECTED TO MOVE 
WELL AHEAD OF THE FRONT...REACHING BAJA CALIFORNIA OVERNIGHT FRI 
NIGHT.

$$
SCHAUER CLARK