000
AXPZ20 KNHC 121556
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON APR 12 2010

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 
1545 UTC.

...ITCZ...

AXIS EXTENDS ALONG 05N77W TO 07N91W TO 02N125W TO 05N132W TO 
03N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
OBSERVED FROM 03N TO 08N BETWEEN 82W AND 100W...AND WITHIN 30 NM 
EITHER SIDE OF A LINE FROM 06N100W TO 09N116W...AND WITHIN 150 
NM OF 01N104W...AND ALSO WITHIN 30 NM EITHER SIDE OF A LINE 
EXTENDING FROM 00N110W TO 04N126W TO 01N134. 

...DISCUSSION...

A DEEP LAYERED CYCLONE IS CENTERED WELL N OF AREA WITH A  
NEGATIVE TILT SHORTWAVE UPPER TROUGH EXTENDING SE TO 27N113W. AN 
UPPER ANTICYCLONE IS CENTERED NEAR 12N118W WITH A RIDGE 
EXTENDING W TO BEYOND 11N140W...AND A RIDGE EXTENDING NE TO 
17N97W. UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG THE ITCZ 
BETWEEN 108W AND 132W. THE RESULTANT DEBRIS MOISTURE IS FANNING 
OUT WITHIN THE RIDGE OVER THE DISCUSSION AREA S OF 17N BETWEEN 
110W AND 128W...WITH SOME MOISTURE CONTINUING NE ALONG THE 
PREVIOUSLY MENTIONED NE UPPER RIDGE EVAPORATING OVER OLD MEXICO 
FROM 19N TO 25N. A THIN LINE OF DEBRIS MOISTURE...ORIGINATING 
FROM ITCZ CONVECTION W OF AREA BETWEEN 150W AND 165W...IS 
STREAMING NE ALONG THE N PERIPHERY OF THE RIDGE...ROUGHLY WITH 
180 NM OF LINE 22N140W TO 21N120W TO OVER OLD MEXICO AT 20N 
WHERE IT MERGES WITH THE OTHER TROPICAL PLUME. A BAND OF VERY 
DRY UPPER AIR IS NOTED N OF THIS MOISTURE BAND...ROUGHLY N OF 
POINTS 27N140W TO 23N120W TO 26N106W. 

AN UPPER SHORTWAVE TROUGH OVER THE SE UNITED STATES EXTENDS SW 
ACROSS THE GULF OF MEXICO AND THE BAY OF CAMPECHE TO A BASE OVER 
THE E PACIFIC AT 14N94W. AN UPPER RIDGE EXTENDS W FROM THE 
COLOMBIA TO A SHARP CREST AT 09N98W. CONVECTION ALONG THE ITCZ 
BETWEEN W COLOMBIA AND 108W IS ENHANCED BY THE UPPER 
DIFFLUENCE...WITH SOME OF THE DEBRIS MOISTURE NOW ADVECTED NE 
ALONG THE PERIPHERY OF THIS TROPICAL RIDGE OVER THE SE 
CARIBBEAN. SOME OF THE MOISTURE IS ALSO SPREADING S ACROSS THE 
EQUATOR BETWEEN 90W AND 125W. OTHERWISE...THE UPPER LEVELS ARE 
DRY OVER THE TROPICAL PACIFIC FROM 08N TO 18N E OF 103W.

AT THE SURFACE...A COLD FRONT IS BEGINNING TO WEAKEN FROM 
32N116W TO 21N140W AND IS EXPECTED TO CONTINUE E REACHING THE 
NORTHERN BAJA PENINSULA MON NIGHT BEFORE LOSING IDENTITY.  A 
RIDGE WILL BUILD SE ACROSS THE AREA IN THE WAKE OF THE FRONT. NE 
TRADES AT 15 TO 20 KT GENERALLY COVER THE AREA FROM 08N TO 15N W 
OF 125W. ASSOCIATED NE SWELL IS MIXING WITH SW SWELL THAT HAS 
BEEN PROPAGATING NE OVER THE AREA E OF 130W...AND NOTED AS FAR N 
AS SOUTHERN CALIFORNIA. 

GAP WINDS...
GULF 0F TEHUANTEPEC...NORTHERLY 15 TO 20 KT DRAINAGE WINDS ARE 
EXPECTED TO DIMINISH TODAY OVER THE WATERS N OF 15N BETWEEN 94W 
AND 96W.

GULF OF PAPAGAYO...PERSISTENT NE TRADES TRADES OVER THE W  
CARIBBEAN SEA WILL CONTINUE TO FUNNEL THROUGH THE GULF OF 
PAPAGAYO AT 20 TO 25 KT THROUGH TONIGHT THEN DIMINISH BELOW 20 
KT LATE TUE.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NELSON