000
AXPZ20 KNHC 161420
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON MAR 16 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 
1515 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 07N77W TO 07N90W TO 00N110W TO 
00N115W TO 05N130W TO 03N140W. ISOLATED MODERATE AND 
OCCASIONALLY STRONG CONVECTION IS FLARING WITHIN 30 NM OF LINE 
FROM 10N123W TO 06N125W TO 04N130W.

...DISCUSSION...

AN UPPER TROPICAL ANTICYCLONE IS NEAR 06N143W WITH A SHORTWAVE 
RIDGE EXTENDING NE TO 16N130W WITH THE RIDGE CREST ERODING WITH 
TIME. ANOTHER TROPICAL UPPER ANTICYCLONE IS ILL DEFINED BUT 
ESTIMATED AT 10N78W. A LONGWAVE RIDGE DOMINATES MOST OF N 
AMERICA WITH AN EMBEDDED POSITIVE TILT SHORTWAVE TROUGH 
DISSECTING THE CONUS FROM THE GREAT LAKES TO SW TEXAS AND 
CONTINUING SW ACROSS THE SOUTHERN BAJA PENINSULA OVER THE 
TROPICAL PAC INTO A SMALL UPPER CYCLONES AT 12N110W AND 05N118W. 

DRY UPPER AIR IS ROTATING THROUGH THE UPPER TROUGH COVERING THE 
DISCUSSION AREA N OF 24N BETWEEN 125W AND 95W. UPPER MOISTURE IS 
NOTED UNDER THE WESTERN UPPER RIDGE...ROUGHLY FROM 11N TO 23N 
BETWEEN 120W AND 150W. THE UPPER LEVELS ARE DRY SE OF A LINE 
FROM NW FLORIDA ACROSS CENTRAL OLD MEXICO TO THE EQUATOR AT 125W.

AT THE SURFACE...A 1025 MB HIGH PRES CENTER NEAR 29N130W HAS A 
RIDGE EXTENDING SE TO NEAR 12N105W. TO THE E OF THE RIDGE 
NORTHERLY WINDS ARE 15 TO 20 KT WITH ASSOCIATED N SWELLS MERGING 
WITH LONG PERIOD S SWELL THAT ORIGINATES IN SOUTHERN HEMISPHERE
AND IS OBSERVED AS EITHER PRIMARILY OR SECONDARY SWELL AS FAR N 
AS SOUTHERN CALIFORNIA. SW OF THE RIDGE THE GRADIENT IS 
SUPPORTING A SWATH OF 20 KT NE TO E TRADES WINDS...BUT THESE 
CONDITIONS ARE EXPECTED TO DIMINISH SOME OVER THE NEXT FEW DAYS 
AS THE ASSOCIATED SURFACE HIGH PRES SHIFTS N OF THE AREA.

CENTRAL AMERICAN GAPS...NE WINDS CONTINUE TO BRIDGE INTO AND 
JUST DOWNSTREAM OF THE GULF OF PAPAGAYO. N WINDS AT 15 KT GULF 
OF PAPAGAYO BUT MAY PULSE TO 20 KT. EXPECTED N WINDS TO INCREASE 
EARLY TONIGHT IN THE GULF OF TEHUANTEPEC AS GUIDANCE MOVES A 
REINFORCING COLD FRONT ACROSS THE GULF OF MEXICO. EXPECT THESE 
WINDS TO INCREASE BRIEFLY TO GALE FORCE LATE TONIGHT AND 
CONTINUE THROUGH LATE MORNING TUE.    

$$
NELSON