000
AXPZ20 KNHC 281529
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED APR 28 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 
1515 UTC.

...ITCZ...
AXIS ALONG 09N84W TO 09N95W TO 07N99W TO 05N109W TO 03N. 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 02N TO 
09N E OF 90W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION 
IS WITHIN 150 NM S AND 200 NM N OF THE AXIS BETWEEN 101W AND 
112W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 120 NM OF THE AXIS W OF 135W.

...DISCUSSION...
A LONGWAVE UPPER TROUGH CONTINUES TO SLIDE EASTWARD OVER BAJA 
CALIFORNIA AND NORTHERN MEXICO N OF 24N WITH AN EMBEDDED UPPER 
LEVEL SHORTWAVE TROUGH ACROSS SE TEXAS AND NE MEXICO...EXTENDING 
SW INTO THE AREA TO THE BASE OF THE TROUGH NEAR 24N110W. UPPER 
LEVEL MOISTURE IN THE FORM OF CIRRUS CLOUDS ARE RIDING THE TAIL 
END OF A 70-90 KT JET ALONG 22N E OF 125W. OTHERWISE THE UPPER 
LEVELS ARE GENERALLY DRY AND STABLE N OF 20N.

AN UPPER LEVEL RIDGE EXTENDS WESTWARD ACROSS THE TROPICAL 
PACIFIC ALONG 13N85W TO 13N117W TO 22N133W. ITCZ CONVECTION IS 
ENHANCED BETWEEN 101W AND 126W WITH THE DEBRIS MOISTURE ADVECTED 
NE ACROSS THE RIDGE GENERALLY REMAINING S OF 20N. CONVECTION IS 
ALSO ENHANCED OVER THE TROPICAL PACIFIC FROM 02N TO 10N E OF 
105W WHERE THE RESULTANT DEBRIS MOISTURE FANS OUT...WITH 
MOISTURE ADVECTING NE ACROSS CENTRAL AMERICA AND MOISTURE 
HEADING S OF THE EQUATOR E OF 105W.

ELSEWHERE AT THE SURFACE...
A COLD FRONT IS LOSING IDENTITY FROM 32N118W TO 24N140W. N TO NE 
WINDS W OF THE FRONT ARE EXPECTED TO PERSIST ON THE EASTERN 
PERIPHERY OF A STRONG 1030 MB HIGH CENTERED NEAR 33N147W. NW 
SWELLS CONTINUE TO PROPAGATE SOUTHEASTWARD INTO THE AREA AND 
MERGE WITH LONGER PERIOD CROSS EQUATORIAL SW SWELL IN THE DEEP 
TROPICS. THE PRESSURE GRADIENT IS FORECAST TO INCREASE OVER THE 
NE PORTION OF THE DISCUSSION AREA OFF THE COAST OF BAJA 
CALIFORNIA BY THIS EVENING REMAINING STRONG UNTIL LATE FRIDAY  
WITH NORTHERLY WINDS GRADUALLY INCREASING 20 TO 30 KT OVER MOST 
OF THE AREA N OF 20N E OF 129W BY EARLY FRIDAY. SOUTHERLY 
MONSOON WINDS WILL INCREASE TO 20 TO 25 KT OVER THE AREA S OF 
06N E OF 90W THURSDAY AND CONTINUE THROUGH THE WEEKEND. GLOBAL 
GFS MODEL GUIDANCE DEPICTS A DEVELOPING AREA OF LOW PRESSURE 
SOUTH OF COSTA RICA THROUGH THE FORECAST PERIOD...WHILE MOST 
OTHER MODELS...INCLUDING THE ECMWF AND UKMET DOWNPLAY 
DEVELOPMENT CONSIDERABLY SW OF THE CENTRAL AMERICA COASTLINE. 
DUE TO WEAK LOW-LEVEL TROUGHING...INSTABILITY...AND IMPLIED 
ATMOSPHERIC LIFT...THE MOST LIKELY IMPACTS WILL BE CONTINUED 
AREAS OF SCATTERED MODERATE CONVECTION AND ISOLATED STRONG 
CONVECTION OVER THE SE PACIFIC AND CENTRAL AMERICA THROUGH EARLY 
NEXT WEEK.

$$
HUFFMAN