000
AXPZ20 KNHC 060939
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAR 06 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

...ITCZ...

AXIS ALONG 05N77W TO 02N110W TO 03N140W. SCATTERED MODERATE 
WITHIN 90 NM S OF THE AXIS BETWEEN 86W AND 92W. 

...DISCUSSION...

SHARP POSITIVELY TILTED LONGWAVE TROUGH DOMINATES WESTERN N 
AMERICA AND EXTENDS SW OFF THE CENTRAL COAST OF CALIFORNIA OVER 
THE E PACIFIC INTO THE DISCUSSION AREA THROUGH 32N126W TO 
28N140W. A NARROW BAND OF UPPER LEVEL DRY AIR WAS OBSERVED 
WITHIN 60-90 NM OF THE TROUGH AXIS AND IS SINKING SWD WITH TIME. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE ISTHMUS OF 
TEHUANTEPEC NEAR 17N94W WITH A RIDGE EXTENDING N TO WELL BEYOND 
32N90W. A BROAD BELT OF STRONG WESTERLY FLOW ALOFT WAS ADVECTING 
UPPER LEVEL DEBRIS MOISTURE...ORIGINATING FROM CONVECTION IN THE 
TROPICAL CENTRAL PACIFIC EASTWARD AND AROUND THE WRN PERIPHERY 
OF THIS UPPER RIDGE...ROUGHLY WITHIN 300 NM EITHER SIDE OF 
POINTS 18N140W TO 21N120W TO BEYOND 32N103W THEN SPILLING 
EASTWARD ACROSS THE RIDGE OVER THE MIDDLE  MISSISSIPPI 
VALLEY...WITH SOME OF THE MOISTURE REACHING NE FLORIDA BEFORE 
EVAPORATING.

FURTHER S...A FLAT UPPER RIDGE EXTENDS N ACROSS THE EQUATOR WITH 
AXIS THROUGH 14N140W. THE ASSOCIATED ANTICYCLONIC FLOW IS 
ADVECTING UPPER MOISTURE OVER THE DISCUSSION AREA S OF 13N W OF 
125W.   

A LONGWAVE TROUGH OVER THE WESTERN N ATLC DEGENERATES INTO A 
SHEAR AXIS WHICH EXTENDS SW ACROSS CENTRAL AMERICA THROUGH 
NICARAGUA/13N84W TO 08N100W. CONVECTION ALONG THE PACIFIC ITCZ 
WAS ENHANCED BETWEEN 86W AND 92W...WITH THE DEBRIS MOISTURE NOW 
ADVECTED NE OVER COSTA RICA AND THE SW CARIBBEAN. OTHERWISE THE 
UPPER LEVELS APPEAR VERY DRY E OF 110W.

AT THE LOW LEVELS...A RIDGE IS BUILDING E ACROSS THE AREA ALONG 
30N133W TO 19N110W. NW SWELLS ARE PROPAGATING SE ACROSS THE 
WATERS W OF 110W MERGING WITH NE SWELLS S OF THE RIDGE AXIS. 

GAP WINDS...N WINDS IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
HAVE DIMINISHED TO 20 TO 25 KT PER A 0058 UTC QUIKSCAT PASS... 
AND ARE EXPECTED TO FURTHER DIMINISH BELOW 20 KT FRI NIGHT. 
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 LATER TODAY. THESE GAP WINDS ARE GENERATING A SWATH OF NE 
SWELL THAT PROPAGATES W TO AROUND 110W MIXING WITH THE TRAIN OF 
NW SWELLS MENTIONED ABOVE. CARIBBEAN TRADES ARE SURGING THROUGH 
THE ISTHMUS OF PANAMA MAINTAINING A 20 TO 25 KT NORTHERLY FLOW 
THROUGH THE GULF OF PANAMA...EXPECTED TO CONTINUE THROUGH SAT 
WITH MINIMAL GALE CONDITIONS ALONG THE NW COAST OF COLOMBIA.   

$$
COBB