000
AXPZ20 KNHC 172129
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT APR 17 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...

ITCZ AXIS IS CENTERED ALONG 07.5N78W TO 06N88W TO 07N99W TO 
05N115W TO 08N128W TO 05.5N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 180 NM N OF AXIS AND 90 NM S OF AXIS 
BETWEEN 95W AND 103W. SCATTERED MODERATE CONVECTION WITHIN 280 
NM S OF AXIS BETWEEN 111W AND 118W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 340 NM S OF AXIS BETWEEN 122W AND 127W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM N OF 
AXIS BETWEEN 127W AND 132W.  

...DISCUSSION...

A WELL DEFINED UPPER LEVEL CYCLONIC VORTEX EMBEDDED IN A DEEP 
LAYER TROUGH IS OBSERVED ON SATELLITE WATER VAPOR IMAGERY TO BE 
NEAR 28N140W. ASSOCIATED SURFACE LOW 1006MB IS ALSO CENTERED 
NEAR 28N140W WITH A COLD FRONT EXTENDING TO 30N134W TO 25N134W 
TO 21N140W. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 11N117W WITH A 
HIGHLY AMPLIFIED RIDGE EXTENDING N TO WELL BEYOND THE AREA TO 
OVER THE WESTERN U.S.. BROAD ANTICYCLONIC CIRCULATION COVERS THE 
AREA E OF THE UPPER TROUGH MENTIONED IN THE PREVIOUS PARAGRAPH 
TO 103W. EAST OF THE LARGE THIS UPPER LEVEL ANTICYCLONE...A HIGH 
AMPLITUDE TROUGH PREVAILS WITH AXIS EXTENDING FROM THE CENTRAL 
GULF OF MEXICO SWD ACROSS SE MEXICO AND GUATEMALA...INTO THE E 
PACIFIC TO 00N91W. 

ELSEWHERE AT THE SURFACE...A 1020 MB HIGH IS CENTERED NEAR 
26N122W. THIS WEAKENING HIGH IS STILL MAINTAINING A SMALL AREA 
OF 20 KT TRADES FROM 07N TO 12N BETWEEN 123W AND 130W. THE HIGH 
IS FORECAST TO DISSIPATE DURING THE NEXT 24 HRS...WHICH WILL 
DECREASE THE COVERAGE OF 20 KT TRADES AS THE PRESSURE GRADIENT 
RELAXES. 

THE DISSIPATING HIGH WILL ALSO ENABLE THE 1006 MB LOW AND COLD 
FRONT MENTIONED IN THE FIRST PARAGRAPH TO PROGRESS EAST OVER THE 
THE FAR N PORTION OF THE AREA...REACHING 28N127W IN 48 HRS. 
EXPECT SEAS TO MAX OUT TO ABOUT 16 FT IN A NW SWELL BEHIND THE 
FRONT OVERNIGHT.

$$
AL/AGUIRRE