000
AXPZ20 KNHC 060332
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI MAR 06 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 04N93W TO 02N105W TO 03N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 60 NM 
EITHER SIDE OF LINE FROM 06N85W TO 04N93W AND ALSO WITHIN 30 NM 
OF 04N137W.

...DISCUSSION...

A POSITIVE TILT LONGWAVE TROUGH DOMINATES WESTERN N AMERICA 
EXTENDING SE OFF THE N COAST OF CALIFORNIA OVER THE E PACIFIC 
INTO THE DISCUSSION AREA FROM 32N127W TO 28N140W. A NARROW BAND 
OF DRY UPPER AIR IS OBSERVED FROM A SMALL EMBEDDED UPPER CYCLONE 
NEAR 36N121W TO 31N130W TO BEYOND 31N145W...AND IS MOVING S WITH 
TIME. JUST S OF THIS DRY AIR IS A BAND OF UPPER MOISTURE THAT 
SWEEPS CYCLONICALLY E THROUGH THE LONGWAVE TROUGH EVENTUALLY 
REACHING THE UPPER LEVELS OVER SOUTHERN CALIFORNIA AND ARIZONA. 

AN UPPER ANTICYCLONE IS CENTERED NEAR 17N932W WITH A RIDGE 
EXTENDING N TO WELL BEYOND 32N92W COLLAPSING SE OVER THE 
TENNESSEE VALLEY ATTM. 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 210 NM EITHER SIDE OF POINTS 17N140W TO 21N120W 
TO BEYOND 32N103W THEN SPILLING EASTWARD ACROSS THE RIDGE OVER 
THE LOWER MISSISSIPPI VALLEY...WITH SOME OF THE MOISTURE 
REACHING NE FLORIDA BEFORE EVAPORATING.

FURTHER S...AN UPPER RIDGE EXTENDS N ACROSS THE EQUATOR CRESTING 
ALONG 14N140W TO 00N126W. 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 HAS AN UPPER TROUGH 
EXTENDING SW ACROSS CENTRAL AMERICA ALONG 13N84W TO 08N100W. 
CONVECTION ALONG THE PACIFIC ITCZ WAS ENHANCED BETWEEN 83W AND 
94W...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 
30N135W TO 20N107W. 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 AND EXPECTED TO FURTHER DIMINISH 
BELOW 20 KT LATE FRI. 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 LATE TONIGHT. 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.   

$$
NELSON