000
AXPZ20 KNHC 050322
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU MAR 05 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 
0315 UTC.

...ITCZ...
AXIS ALONG 04N77W TO 04N94W TO 02N112W TO 03N134W TO 02N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 
150 NM OF 06N87W AND ALSO WITHIN 30 NM OF 03N133W.

...DISCUSSION...

A LONGWAVE TROUGH DOMINATES WESTERN N AMERICA AND THE EASTERN N 
PACIFIC WITH ITS MEAN AXIS EXTENDING S INTO THE DISCUSSION AREA 
FROM 32N130W TO 20N137W. A BAND OF DRY UPPER AIR IS OBSERVED 
NEAR THE BASE OF THE TROUGH...ROUGHLY FROM 21N TO 26N BETWEEN 
129W AND 143W. FURTHER N...A BAND OF UPPER MOISTURE IS SWEEPING 
CYCLONICALLY E THROUGH THE TROUGH EVENTUALLY REACHING THE UPPER 
LEVELS OVER CENTRAL CALIFORNIA. 

AN UPPER ANTICYCLONE IS CENTERED NEAR 22N106W WITH A RIDGE 
EXTENDING N TO WELL BEYOND 32N96W...AND DOMINATING THE UPPER 
LEVELS OF THE CONUS. UPPER DEBRIS MOISTURE...ORIGINATING FROM 
CONVECTION IN THE TROPICAL CENTRAL PACIFIC...CONCENTRATES INTO A 
PLUME SPREADING NE AROUND THE W PERIPHERY OF THIS UPPER 
RIDGE...ROUGHLY WITHIN 180 NM EITHER SIDE OF POINTS 15N140W TO 
25N122W TO BEYOND 32N111W THEN SPILLING EASTWARD ACROSS THE 
RIDGE OVER THE CENTRAL CONUS. SOME OF THIS DEBRIS MOISTURE IS 
NOW PLUNGING SE OVER THE NE GULF OF MEXICO AND N FLORIDA BUT 
SEEMS TO EVAPORATE ALONG 28N ATTM. 

A LONGWAVE TROUGH OVER THE WESTERN N ATLC HAS AN UPPER TROUGH 
EXTENDING SW ALONG 20N74W TO 11N84W TO A SMALL STATIONARY UPPER 
CYCLONE AT 06N98W. CONVECTION ALONG THE PACIFIC ITCZ WAS 
ENHANCED BETWEEN 83W AND 90W...WITH THE DEBRIS MOISTURE ADVECTED 
NE OVER COSTA RICA AND THE SW CARIBBEAN WITH SOME OF THE 
MOISTURE CONTINUING NE IN TRANSVERSE BANDING ACROSS HISPANIOLA.  
OTHERWISE THE UPPER LEVELS APPEAR VERY DRY E OF 115W.

AT THE LOW LEVELS...A WEAK COLD FRONT IS LOSING IDENTITY FROM 
SOUTHERN CALIFORNIA TO NEAR 29N122W. A RIDGE IS BUILDING E 
ACROSS THE AREA ALONG 27N140W TO 27N120W TO 17N112W. NW SWELLS 
ARE PROPAGATING SE ACROSS THE WATERS W OF 110W. 

GAP WINDS...N WINDS IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
HAVE WEAKENED TO 20 KT EXCEPT 20 TO 25 KT BETWEEN 1200 AND 1400 
UTC DAILY. NE WINDS IN THE GULF OF FONSECA AND THE GULF OF 
PAPAGAYO CONTINUE AT 20 TO 30 KT...AND EXPECTED TO DIMINISH TO 
20 TO 25 KT THU AND FRI DOWNSTREAM OF PAPAGAYO. THESE GAP WINDS 
ARE GENERATING A SWATH OF NE SWELL THAT PROPAGATES W TO AROUND 
115W MIXING WITH THE TRAIN OF NW SWELLS MENTIONED ABOVE. 
CARIBBEAN TRADES ARE SURGING THROUGH THE ISTHMUS OF PANAMA 
MAINTAINING A 20 KT NORTHERLY FLOW THROUGH THE GULF OF PANAMA 
WELL INTO FRI.  

$$
NELSON