000
AXPZ20 KNHC 291531
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU APR 29 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 
1445 UTC.

...ITCZ...
AXIS ALONG 09N84W TO 05N110W TO 07N123W TO 05N140W. SCATTERED 
MODERATE TO STRONG WITHIN 120 NM N AND 180 NM S OF AXIS BETWEEN 
90W AND 105W...AND WITHIN 90 NM OF THE AXIS BETWEEN 120W AND 
125W. SCATTERED MODERATE ISOLATED WITHIN 120 NM S OF AXIS 
BETWEEN 85W AND 90W.

...DISCUSSION...
BROAD LONGWAVE UPPER LEVEL TROUGH OVER THE WRN CONUS CONTINUES 
TO DIG SLOWLY SWD WITH TIME. A SHEAR AXIS EXTENDING FROM  THE 
BASE OF THROUGH OVER SRN CALIFORNIA CONTINUES SW THROUGH 27N130W 
TO 22N140W. THIS FEATURE IS EFFECTIVELY FLATTENING THE CREST OF 
BROAD MID/UPPER LEVEL RIDGE AND ASSOCIATED ELONGATED ANTICYCLONE 
ALONG 11N BETWEEN 110W AND 120W. A CAST AREA OF DRY AIR ALOFT 
WAS LOCATED OVER MOST OF MEXICO AND THE PACIFIC N OF 20N FROM 
BAJA CALIFORNIA THROUGH 140W.  

MODERATE TO STRONG UPPER LEVEL DIFFLUENT FLOW SE OF THE 
ELONGATED ANTICYCLONE CONTINUES TO ENHANCE DEEP CONVECTION ALONG
AND TO THE WEST OF A PERSISTENT SURFACE TROUGH ALONG 87W...AND
ALONG THE ITCZ BETWEEN 90W AND 105W. THIS SURFACE TROUGH IS PART 
OF A BROAD AREA OF LOWER PRESSURES OVER CENTRAL AMERICA. NWP 
MODELS FORECAST A CONTINUATION OF LOWER PRESSURES OVER MEXICO 
AND CENTRAL AMERICA THROUGH THE NEXT 48 HOURS WITH A BROAD AREA 
OF SW WINDS TO 20 KT ADVECTING TROPICAL MOISTURE AGAINST THE 
MOUNTAIN RANGES OF GUATEMALA...HONDURAS AND EL SALVADOR. 

ELSEWHERE AT THE SURFACE...
FRONTAL TROUGH WHICH EXTENDED FROM 30N115W TO 22N140W EARLIER 
HAS DISSIPATED. IN ITS PLACE A FAIRLY STRONG AREA OF HIGH PRES 
1033 MB CENTERED NEAR 33N145W IS FORECAST TO BUILD EWD OVER THE 
NEXT 48 HOURS AND TIGHTEN THE PRES GRADIENT ALONG THE BAJA 
CALIFORNIA W COAST WITH NW WINDS INCREASING TO 20 TO 30 KT.
IN ADDITION THE STRENGTHENING RIDGE WILL ALLOW THE AREA OF NE 
TRADES TO INCREASE AND EXPAND IN AREAL COVERAGE OVER THE NEXT 24 
TO 36 HOURS. MODERATE TO STRONG WINDS COUPLED WITH A LONG FETCH 
ON E SIDE OF RIDGE WILL RESULT IN LARGE LONG PERIOD SWELLS 
TO SPREAD SE ACROSS BASIN AND EVENTUALLY MERGE WITH CROSS 
EQUATORIAL SW SWELL S OF 10N.  

WEAK TROUGH EMBEDDED IN ITCZ ALONG 123W FROM 02N-09W IS UNDER 
FAVORABLE ENVIRONMENT ALOFT WHICH ENHANCES DEEP CONVECTION AS IT 
MOVES W. SCATTERED MODERATE TO STRONG CONVECTION NOTED IN 
ASSOCIATION WITH THIS TROUGH HOWEVER THERE APPEARS TO BE LITTLE 
OR NO ORGANIZATION. 

$$
COBB