000
AXPZ20 KNHC 031539
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI APR 03 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 
1530 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 08N82W 
TO 03N100W TO 05N121W TO 04N140W. ISOLATED MODERATE WITHIN 60 NM 
OF AXIS FROM 88W TO 90W...WITHIN 90 NM OF AXIS FROM 110W TO 
115W...AND WITHIN 60 NM S OF AXIS BETWEEN 139W AND 140W.

...DISCUSSION...
AT THE SURFACE...A 1031 MB HIGH CENTERED NW OF DISCUSSION AREA 
NEAR 41N136W EXTENDS A RIDGE THROUGH THE REGION FROM 30N137W TO 
20N118W. THE PRES GRADIENT BETWEEN THE RIDGE AND THE ITCZ HAS 
THE WINDS UP TO 20 KT N OF THE ITCZ WEST OF 130W...AND ALSO IN 
THE 20 TO 25 KT RANGE N OF 28N BETWEEN 119W AND 125W AS THE 
RIDGE INTERACTS WITH LOWER PRES OVER THE SW CONUS. THE TRADES 
ARE EXPECTED TO DIMINISH BELOW 20 KT LATE SAT AS THE HIGH MOVES 
SE WHILE WEAKENING. N TO NW SWELL WILL CONTINUE TO PUSH INTO THE 
WATERS OFF THE NORTHERN BAJA PENINSULA...DRIVEN BY STRONG WINDS 
N OF THE AREA FROM PT ARENA TO PT CONCEPTION. SEAS CURRENTLY IN 
THE 8 TO 13 FT RANGE WILL BUILD CLOSE TO 15 FT TONIGHT JUST OF 
THE S CALIFORNIA COAST...THEN SUBSIDE TO ABOUT 10 FT EARLY SUN 
AS THE WINDS DIMINISH WITH HIGH PRES WEAKENING N OF THE REGION. 
ALSO...GOES IR IMAGERY SHOWS A LARGE AREA OF LOW LEVEL 
CLOUDINESS N OF 13N...WITH SKIES MOSTLY BROKEN TO OVERCAST.

THE WEAK UPPER TROUGH STRETCHED OVER N WATERS FROM 30N116W TO 
23N132W WILL BE EXTEND WESTWARD...BEING REINFORCED BY A STRONG 
SHORTWAVE MOVING INTO THE GREAT BASIN BY SAT. THE WESTERN 
PORTION OF THE TROUGH THEN BECOMES ABSORBED BY ANOTHER STRONG 
UPPER LOW ON SUN...AS THE ASSOCIATED COLD FRONT MOVES INTO THE 
AREA FROM THE NW. NW SWELL BEHIND THE FRONT IN THE 10 TO 15 FT 
RANGE WILL MOVE INTO THE AREA SUN...ACCOMPANIED BY ISOLATED 
SHOWERS ALONG THE FRONT.  

GOES IMAGERY INDICATED A LARGE AREA OF UPPER LEVEL 
MOISTURE...COINCIDENT WITH THE SUBTROPICAL JET EXTENDING FROM 
THE BAJA PENINSULA NEAR 26N TO 19N121W...THEN TURNING MORE W TO 
17N140W. THE MODEL GUIDANCE INDICATES THAT THE 110-115 KT WINDS 
NEAR 26N113W WILL MIGRATE E OVER THE NEXT DAY...AND THAT ANOTHER 
MAXIMUM 0F 115 KT WILL PUSH INTO THE REGION FROM THE W TO 
20N138W ON SAT. THE WATER VAPOR IMAGERY ALSO INDICATES A LARGE 
REGION OF DRY UPPER AIR...COINCIDENT WITH THE SUBSIDENCE OF THE 
LEVEL HIGH NEAR 14N98W.

$$
KELLS/CHRISTENSEN