000
AXPZ20 KNHC 131550
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE APR 13 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 FROM 02N78W TO 09N117W TO 06N112W TO 07N126W 
TO 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
OBSERVED FROM 02N TO 08N BETWEEN 78W AND 89W...AND WITHIN 120 NM 
EITHER SIDE OF THE ITCZ AXIS BETWEEN 90W AND 100W...AND ALSO 
FROM 112W TO 10N125W. 

...DISCUSSION...

A DEEP LAYERED CYCLONE IS CENTERED WELL N OF AREA WITH A  
NEGATIVE TILT SHORTWAVE UPPER TROUGH EXTENDING SE ACROSS OLD 
MEXICO ALONG 32N111W TO A BASE AT 18N95W. A SECOND UPPER SHORT 
WAVE IS ROTATING CYCLONICALLY AROUND THE SAME CYCLONE OVER THE 
NW PORTION WITH ITS AXIS FROM 32N130W TO 28N132W. AN UPPER 
ANTICYCLONE IS QUASI STATIONARY NEAR 12N122W WITH A RIDGE 
EXTENDING E AND W ALONG 12N FROM 102W TO BEYOND 140W...AND 
A RIDGE ALSO EXTENDS N TO A CREST AT 30N119W EFFECTIVELY 
SEPARATING THE TWO UPPER TROUGHS PREVIOUSLY DESCRIBED. UPPER 
DIFFLUENCE IS ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 109W 
AND 124W WITH DEBRIS MOISTURE ADVECTED S ACROSS THE EQUATOR 
BETWEEN 100W AND 125W. CONVECTION WAS ALSO ENHANCED EARLIER 
BETWEEN 130W AND 145W...WITH THE RESULTANT DEBRIS MOISTURE 
CONCENTRATING INTO A 300 NM WIDE PLUME CENTERED ALONG POINTS 
15N140W TO 22N125W TO NEAR 22N115W WHERE THE MOISTURE 
EVAPORATES. OTHERWISE...DRY UPPER AIR IS NOTED N OF A LINE FROM  
21N140W TO 29N121W TO 18N100W.
 
AN UPPER RIDGE EXTENDS W FROM THE COLOMBIA TO A SHARP CREST AT 
09N104W. CONVECTION ALONG THE ITCZ BETWEEN W COLOMBIA AND 100W 
IS ENHANCED BY THE UPPER DIFFLUENCE...WITH THE DEBRIS MOISTURE E 
OF 90W 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 100W. OTHERWISE...THE UPPER 
LEVELS ARE DRY OVER THE TROPICAL PACIFIC N OF THE THE ITCZ TO 
ALONG 20N E OF 130W.

AT THE SURFACE...A COLD FRONT IS WEAKENING FROM THE NORTHERN 
BAJA PENINSULA TO NEAR 24N125W WITH A RIDGE BUILDING SE IN ITS 
WAKE. NE TRADES AT 15 TO 20 KT GENERALLY COVER THE AREA FROM 10N 
TO 20N W OF 120W. THE ASSOCIATED NE SWELL IS MIXING WITH SW 
SWELL THAT HAS BEEN PROPAGATING N ACROSS THE THE AREA AND IS 
NOTED AS FAR N AS THE CENTRAL BAJA PENINSULA. THE SOUTHERLY 
SWELL IS ALSO MIXING WITH NW SWELL PROPAGATING SOUTHEASTWARD  
IN THE WAKE OF THE COLD FRONT...GENERALLY OVER THE WATERS N OF 
10N W OF 115W.

GAP WINDS...
GULF 0F TEHUANTEPEC...NORTHERLY 15 KT DRAINAGE WINDS ARE  
EXPECTED TO DEVELOP BRIEFLY AGAIN ON WED OVER THE WATERS N OF 
15N BETWEEN 94W AND 96W.

GULF OF PAPAGAYO...NE TRADES TRADES OVER THE W CARIBBEAN SEA 
WILL DIMINISH SOME ON WED WITH THE PERSISTENT 20 KT NE WINDS 
THAT HAVE BEEN FUNNELING THROUGH THE GULF OF PAPAGAYO TO 
DIMINISH BELOW 20 KT BY WED AFTERNOON.

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

$$
NELSON