000
AXPZ20 KNHC 200928
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED APR 20 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 05N77W 
TO 06N93W THEN RESUMES FROM 06N97W TO 05N115W TO 03N132W THEN 
RESUMES FROM 03N135W TO 03N140W. SCATTERED MODERATE TO STRONG 
CONVECTION WAS N OF 05N E OF 79W. SIMILAR CONVECTION WAS WITHIN 
90 NM OF A LINE FROM 00N88W TO 06N93W AND ALSO WITHIN 90 NM OF A 
LINE FROM 10N115W TO 06N122W.

...DISCUSSION...

1021 MB HIGH PRES IS LOCATED NEAR 28N130W WITH A RIDGE EXTENDING 
SE TO NEAR 19N112W. THE HIGH AND RIDGE ARE FORECAST TO DISSIPATE 
WITHIN THE NEXT 24 HOURS AS A COLD FRONT SKIRTS BY TO THE N. 
THIS FRONT WILL NOT BRING ANY SENSIBLE WEATHER CHANGES TO THE 
DISCUSSION WATERS OTHER THAN A BRIEF WIND SHIFT BEFORE HIGH PRES 
REBUILDS IN ACROSS THE AREA BEHIND THE FRONT. CURRENTLY THERE IS 
A SMALL AREA OF 20 KT TRADE WINDS ON THE SOUTHERN PERIPHERY OF 
THE RIDGE FROM 05N TO 14N W OF 133W. MODEL GUIDANCE INDICATES 
LITTLE CHANGE OF THIS AREA OF TRADES DURING THE NEXT COUPLE OF 
DAYS.

THE 0424 UTC EXPERIMENTAL ASCAT 25 KM COASTAL WINDS SHOWED AN 
AREA OF 20 KT NW WINDS N OF 24N WITHIN 120 NM W OF THE BAJA 
CALIFORNIA PENINSULA. WINDS ARE FORECAST TO INCREASE TO 25 KT BY 
THU NIGHT AS THE PRES GRADIENT BETWEEN THE RE-BUILDING HIGH PRES 
BEHIND THE COLD FRONT AND LOWER PRES OVER MEXICO TIGHTENS.

A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 09N93W TO 02N96W. 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 90 
NM EITHER SIDE OF THE TROUGH AXIS. THIS FEATURE WILL MOVE W-NW 
AROUND 5 KT DURING THE NEXT COUPLE OF DAYS. ANOTHER SURFACE 
TROUGH IS ALONG 134W FROM 02N TO 07N WITH SCATTERED MODERATE TO 
STRONG CONVECTION N OF 05N WITHIN 60 NM EITHER SIDE OF THE 
TROUGH. THIS FEATURE WILL MOVE W OF THE AREA BY THU MORNING.

VERY LONG PERIOD 19-21 SECOND CROSS-EQUATORIAL SW SWELL WILL 
SWEEP NE ACROSS THE WATERS DURING THE REMAINDER OF THE WEEK 
REACHING COASTAL AREAS OF SOUTHERN CALIFORNIA...MEXICO AND 
CENTRAL AMERICA THU. WHILE SEA HEIGHTS WILL BE LESS THAN 8 FT AS 
THE SWELL PROPAGATES AWAY FROM THE EQUATOR...THIS HIGH ENERGY 
SWELL WILL STILL RESULT IN VERY HAZARDOUS SURF CONDITIONS AT 
COASTAL LOCATIONS INCLUDING AN ENHANCED RIP CURRENT DANGER THU 
THROUGH SAT.

$$
LEWITSKY