000
AXPZ20 KNHC 251557
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED FEB 25 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 INTERTROPICAL CONVERGENCE ZONE...THE AXIS EXTENDS ALONG 
03N77W TO 05N85W TO 00N105W TO 00N117W TO 02N127W TO 00N140W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 30 NM EITHER SIDE 
OF LINE FROM 06N75W TO 06N79W AND ALSO A LINE FROM 06N89W TO 
05N99W AND ALSO A LINE FROM 07N113W TO 07N118W. SCATTERED 
MODERATE AND ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 120 
NM EITHER SIDE OF LINE FROM 05N125W TO 06N140W.

...DISCUSSION...

A LONG WAVE TROUGH CONTINUES OVER THE EASTERN N PACIFIC WITH ITS 
MEAN AXIS NOW SHIFTED JUST NW OF THE NORTHWESTERN PORTION OF THE 
DISCUSSION AREA. A SHORT WAVE TROUGH IS ROTATING THROUGH THE 
PATTERN AND IS EXPECTED TO JUST CLIP THE EXTREME NW PORTION THU 
NIGHT AND FRI BLOCKED BY A QUASI STATIONARY SURFACE HIGH NEAR 
27N126W 1023 MB. ALTHOUGH THESE WEAK FRONTS HAVE BEEN 
DISSIPATING OVER THE NW PORTION...THEY CONTINUE TO PROPAGATE 
REINFORCING NW SWELLS TO A MAX OF ABOUT 11 FT SE INTO THE AREA. 
BRIEF SHIFTING WINDS...BUT MOSTLY 15 TO 20 KT...ALSO ACCOMPANY 
THE FRONTS.

A LONG WAVE UPPER TROUGH OVER THE WESTERN N ATLANTIC TRAILS AN 
UPPER TROUGH W SW ACROSS THE NW CARIBBEAN AND OLD MEXICO ALONG 
19N AND OVER THE E PACIFIC ALONG 14N110W INTO UPPER CYCLONES AT 
07N123W AND 02N128W. ASSOCIATED UPPER DIFFLUENCE IS ENHANCING 
CONVECTION ALONG THE ITCZ BETWEEN 112W AND 122W. 

W OF THIS UPPER TROUGH...AN UPPER ANTICYCLONE NEAR THE EQUATOR 
AT 15N15W HAS A RIDGE EXTENDING NE OVER THE SW PORTION OF THE 
DISCUSSION AREA. ANOTHER UPPER ANTICYCLONE...MORE DOMINATE...IS 
CENTERED NEAR 18N116W WITH A LONGWAVE RIDGE EXTENDING SW TO 
BEYOND 12N142W AND AN UPPER RIDGE EXTENDING NE TO A SHARP CREST 
OVER E TEXAS AT 29N95W. A SLOT OF DRY UPPER AIR IS NOTED WITHIN 
150 NM EITHER SIDE OF LINE 27N127W TO 32N114W AND IS SHIFTING NE 
WITH TIME. N OF 20N W OF THIS DRY SLOT...UPPER DEBRIS MOISTURE 
IS NOTED AND ALSO WITHIN 150 NM EITHER SIDE OF LINE 16N140W TO 
25N120W TO OVER TEXAS AT 32N97W.

E OF THE UPPER LEVEL TROUGH...AN UPPER ANTICYCLONE IS CENTERED 
NEAR 08N82W WITH A RIDGE EXTENDING W TO 08N110W. UPPER 
DIFFLUENCE UNDER THE RIDGE IS ENHANCING ITCZ CONVECTION BETWEEN 
90W AND 100W. THE UPPER LEVELS APPEAR VERY DRY S OF 20N E OF 
122W.

CENTRAL AMERICAN GAPS...WINDS AND SEAS ARE DIMINISHING IN AND 
DOWNSTREAM OF THE GULF OF TEHUANTEPEC. NE TO E WINDS IN AND 
DOWNSTREAM OF THE GULF OF PAPAGAYO AT 20 TO 25 KNOTS WILL 
CONTINUE FOR SEVERAL MORE DAYS...WITH THESE CONDITIONS MERGING 
WITH FAIRLY STRONG NE TO E TRADES BETWEEN 95W AND 150W. 
NORTHERLY WINDS ARE SURGING TO 20 KT IN AND DOWNSTREAM OF THE 
WESTERN GULF PANAMA. 

$$
NELSON