000
AXPZ20 KNHC 280341
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED APR 28 2010

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 
0245 UTC.

...ITCZ...

AXIS ANALYZED FROM 10N83W TO 05N103W TO 05N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 04N TO 13N 
BETWEEN 83W AND 94W AND WITHIN 150 NM OF 06N101W. SCATTERED 
MODERATE CONVECTION IS NOTED WITHIN 120 NM OF 07N126W.

...DISCUSSION...

A LONGWAVE UPPER TROUGH DOMINATES THE DISCUSSION AREA N OF 25N 
WITH AN EMBEDDED SHORTWAVE UPPER TROUGH...ORIGINATING FROM A 
CYCLONE OVER NORTHERN OLD MEXICO AT 30N104W...EXTENDING SW INTO
THE AREA TO A BASE AT 24N114W. UPPER MOISTURE IS NOTED WITHIN 
THE BROAD TROUGH...ROUGHLY N OF 29N BETWEEN 120W AND 130W. 
OTHERWISE THE UPPER LEVELS ARE DRY N OF 24N W OF 104W.

AN UPPER RIDGE EXTENDS W ACROSS THE TROPICAL PACIFIC ALONG 
11N81W TO 09N120W TO 09N136W. ITCZ CONVECTION WAS ENHANCED 
BETWEEN 111W AND 130W WITH THE DEBRIS MOISTURE ADVECTED NE 
ACROSS THE RIDGE TO ALONG 24N...WHERE MOST OF THE MOISTURE 
EVAPORATES...WITH ONLY A THIN BAND OF MOISTURE CONTINUING E 
ACROSS CENTRAL OLD MEXICO AND OVER THE NW GULF OF MEXICO. 
CONVECTION IS ALSO ENHANCED OVER THE TROPICAL PACIFIC FROM 03N 
TO 12N E OF 103W WHERE THE RESULTANT DEBRIS MOISTURE FANS 
OUT...WITH SOME OF THE MOISTURE CROSSING THE EQUATOR E OF 
100W...AND SOME OF THE MOISTURE ADVECTED NE ACROSS CENTRAL 
AMERICA.

ELSEWHERE AT THE SURFACE...
A COLD FRONT IS LOSING IDENTITY FROM 32N128W TO 27N140W. 
NORTHERLY WINDS W OF THE FRONT WILL VEER TO THE NE TONIGHT INTO 
WED AS NW SWELLS PROPAGATE SE INTO THE AREA AND EVENTUALLY MERGE 
WITH CROSS EQUATORIAL SW SWELL IN THE DEEP TROPICS. THE PRESSURE 
GRADIENT WILL TIGHTEN WED NIGHT INTO FRI WITH NORTHERLY WINDS 
GRADUALLY INCREASING TO 20 TO 25 KT OVER MOST OF THE AREA N OF 
18N BY THU NIGHT. SOUTHERLY MONSOON WINDS WILL INCREASE TO 20 TO 
25 KT OVER THE AREA S OF 09N E OF 96W THROUGH THU.       

$$
NELSON