000
AXPZ20 KNHC 040331
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED MAR 04 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 07N77W TO 03N100W TO 05N127W TO 04N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 30 NM OF LINE FROM 
07N84W TO 04N93W.

...DISCUSSION...

A LONGWAVE TROUGH DOMINATES THE EASTERN N PACIFIC WITH ITS AXIS 
EXTENDING S INTO THE DISCUSSION AREA FROM 32N132W TO 18N138W. A 
BAND OF DRY UPPER AIR IS SWEEPING THROUGH THE PATTERN WITHIN 120 
NM EITHER SIDE OF LINE 32N123W TO 25N140W. AN UPPER ANTICYCLONE 
IS CENTERED AT 19N109W WITH A RIDGE EXTENDING N TO WELL BEYOND 
32N102W...AND DOMINATING THE UPPER LEVELS OF CENTRAL N AMERICA. 
A LONGWAVE TROUGH OVER THE EASTERN SEABOARD OF THE CONUS EXTENDS 
SW ALONG 18N85W TO A BASE NEAR 01N101W. UPPER DEBRIS MOISTURE... 
ORIGINATING FROM CONVECTION IN THE TROPICAL CENTRAL PACIFIC... 
CONCENTRATES INTO A PLUME AROUND THE W PERIPHERY OF THE 
RIDGE...WITHIN 180 NM EITHER SIDE OF POINTS 16N134W TO BEYOND 
32N115W THEN SPILLING EASTWARD ACROSS THE RIDGE OVER THE CENTRAL 
CONUS. SOME OF THIS DEBRIS MOISTURE IS NOW PLUNGING SE OVER 
CENTRAL GULF OF MEXICO. CONVECTION IS ENHANCED ALONG THE ITCZ 
BETWEEN 92W AND 97W...WITH THE DEBRIS MOISTURE ADVECTED NE 
ACROSS COSTA RICA. OTHERWISE THE UPPER LEVELS ARE VERY DRY E OF 
115W.

GAP WINDS...N WINDS IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
WILL CONTINUE TO WEAKEN TO LESS THAN 20 KT THU AFTERNOON. 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 WED AND 
THU...BUT MAY SEE A BRIEF 30 KT JUST AFTER SUNRISE WED. THESE 
GAP WINDS ARE GENERATING A BROAD SWATH OF EASTERLY SWELL THAT 
WILL PROPAGATE W TO AROUND 115W MIXING WITH THE ONGOING NW 
SWELL. CARIBBEAN TRADES ARE PUSHING THROUGH THE ISTHMUS OF 
PANAMA MAINTAINING 20 TO 25 NORTHERLY FLOW THROUGH THE GULF OF 
PANAMA THROUGH THU.  

$$
NELSON