000
AXPZ20 KNHC 010321
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED APR 01 2009

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 
0300 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N77W TO 
02N100W TO 02N120W TO 04N135W TO 03N140W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS WITHIN 70 NM EITHER SIDE OF AXIS 
FROM 83W TO 85W.

...DISCUSSION...

ALOFT...A MID TO UPPER-LEVEL TROUGH EXTENDS SW FROM NORTHERN 
BAJA CALIFORNIA PENINSULA TO NEAR 26N140W. A BRANCH OF THE  
SUBTROPICAL JETSTREAM...WITH CORE WINDS OF 110-130 KT...IS NOTED 
JUST SOUTH OF THE TROUGH WHICH IS EXPECTED TO DRIFT E OVER THE 
NEXT 24 HOURS. A NARROW BAND OF TRANSVERSE HIGH CLOUDS IS 
ASSOCIATED WITH THE JET. A SHORT-WAVE TROUGH IS MOVING EWD 
ACROSS THE WESTERN PORTION OF THE FORECAST AREA. THE AXIS LIES 
ALONG 14N138W 10N137W 6N138W. UPPER DIFFLUENCE AHEAD OF THIS 
TROUGH IS HELPING TO INDUCE ISOLATED SHOWERS FROM 8N TO 11N 
BETWEEN 133W AND 138W. A RIDGE...CENTERED ON A HIGH NEAR 
11.5N108.5W...COVERS MUCH OF THE AREA E OF 124W AND S OF 20N 
INCLUDING SE MEXICO AND NORTHERN CENTRAL AMERICA. MODERATE TO 
STRONG UPPER-LEVEL SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED 
WITHIN THE RIDGE AXIS PARTICULARLY TO THE E AND S OF THE HIGH 
CENTER. SWLY WINDS ON THE WESTERN PERIPHERY OF THIS HIGH ARE 
SUPPORTING SOME CLOUDINESS WITH EMBEDDED SHOWERS FROM 7N T0 10N 
BETWEEN 118W AND 124W. THE RIDGE IS EXPECTED TO REMAIN NEARLY 
STATIONARY OVER THE NEXT 24 HOURS.  

AT THE SURFACE...STRONG HIGH PRES LOCATED NW OF THE DISCUSSION 
AREA NEAR 36N144W HAS A RIDGE EXTENDING SE INTO THE FORECAST 
REGION TO NEAR 14N108W. FRESH TO STRONG TRADE WINDS OF 20 TO 25 
KT ARE FOUND UNDER THE INFLUENCE OF THIS RIDGE MAINLY FROM 11N 
TO 24N W OF 130W. GALE FORCE WINDS ARE OCCURRING N OF THE 
FORECAST AREA NEAR THE COAST OF CALIFORNIA DUE TO THE THIGH PRES 
GRADIENT BETWEEN THIS HIGH AND LOWER PRES OVER THE SW CONUS. THE 
HIGH IS EXPECTED TO REMAIN NW OF THE AREA OVER THE NEXT 24 HOURS 
AS THE RIDGE SLOWLY EXTENDS FURTHER SE INTO THE REGION. AN AREA 
OF MODERATE CONVECTION PERSISTS WITHIN 70 NM EITHER SIDE OF ITCZ 
AXIS FROM 83W TO 85W. LONG PERIOD SWELLS FROM THE SW WILL AFFECT 
THE COAST OF CENTRAL AMERICA LATE TODAY INTO THURSDAY. 

$$
GR