000
AXPZ20 KNHC 162117
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 16 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 05N77W TO 04.5N81W TO 06N94W TO 
03.5N108W TO 06.5N122W TO 05N130W TO 06.5N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM N OF AXIS E OF 
85W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 150 NM N OF 
AXIS AND 90 NM S OF AXIS BETWEEN 85W AND 97W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WITHIN 180 NM N OF AXIS BETWEEN 113W 
AND 116W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 180 NM 
EITHER SIDE OF AXIS W OF 116W.  
 
...DISCUSSION...

A POSITIVELY TILTED UPPER LEVEL TROUGH IS LOCATED JUST NW OF THE 
AREA. FURTHER E...A LARGE AMPLITUDE UPPER LEVEL TROUGH EXTENDS 
OVER THE EASTERN PORTION OF THE AREA FROM THE WESTERN GULF OF 
MEXICO ACROSS SE OLD MEXICO NEAR THE GULF OF TEHUANTEPEC TO NEAR 
00N93W. THIS TROUGH IS ENHANCING ITCZ CONVECTION E OF 97W.  

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 11N122W...WITH 
ANTICYCLONIC FLOW PREVAILING ACROSS THE W PART OF THE AREA. ITCZ 
CONVECTION IS MAINTAINING THIS UPPER LEVEL ANTICYCLONE.

AT THE SURFACE...THE ABOVE MENTIONED UPPER LEVEL TROUGH IS 
SUPPORTING A 1007 MB LOW NEAR 32N146W WITH ASSOCIATED COLD FRONT 
JUST W OF THE AREA. THIS FRONT WILL MOVE E INTO THE AREA TONIGHT 
WITH NEAR GALE FORCE WINDS JUST E OF THE FRONT AS A RESULT OF 
THE LOCALLY TIGHT PRESSURE GRADIENT BETWEEN THE FRONT AND 
STATIONARY HIGH PRESSURE 1021 MB CENTERED NEAR 26N125W.

THE PRESSURE GRADIENT BETWEEN THE ITCZ AND THE SURFACE HIGH 
PRESSURE CENTER MENTIONED IN THE PARAGRAPH ABOVE IS MAINTAINING 
NE TRADES OF 20 TO 25 KT FROM 08N TO 15N BETWEEN 116W AND 131W. 
RESULTANT SHORT PERIOD NE WIND WAVES ARE COMMINGLING WITH LONG 
PERIOD NW SWELL AND CROSS EQUATORIAL LONG PERIOD SW SWELL THAT 
HAS BEEN PROPAGATING N ACROSS THE DISCUSSION AREA FOR SEVERAL 
DAYS RESULTING IN CONFUSED SEAS WHERE THE DIFFERENT WAVE GROUPS 
ARE INTERSECTING.

$$
AL/FORMOSA