000
AXPZ20 KNHC 032138
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 03 2009

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 
2130 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 08N81W 
TO 04N100W TO 03N120W TO 03N140W. ISOLATED MODERATE CONVECTION 
IS WITHIN 140 NM SOUTH OF AXIS BETWEEN 84W AND 91W. 

...DISCUSSION...
AT THE SURFACE...A 1029 MB HIGH CENTERED NW OF DISCUSSION AREA 
NEAR 41N134W EXTENDS A RIDGE THROUGH THE REGION FROM 30N132W TO 
16N112W. THE PRES GRADIENT BETWEEN THE RIDGE AND THE ITCZ HAS 
THE WINDS UP TO 20 KT N OF THE ITCZ WEST OF 127W...AND ALSO IN 
THE 20 TO 25 KT RANGE N OF 28N BETWEEN 119W AND 124W AS THE 
RIDGE INTERACTS WITH LOWER PRES OVER THE SW CONUS. THE TRADES 
ARE EXPECTED TO DIMINISH BELOW 20 KT IN ABOUT 24 HOURS AS THE 
HIGH MOVES SE WHILE WEAKENING. N TO NW SWELL WILL CONTINUE TO 
PUSH INTO THE WATERS OFF THE NORTHERN BAJA PENINSULA...DRIVEN BY 
GALE FORCE WINDS N OF THE AREA...NEAR THE CENTRAL COAST OF 
CALIFORNIA. SEAS ARE CURRENTLY IN THE 9 TO 12 FT RANGE...THEN 
SUBSIDE TO ABOUT 9 FT EARLY SUN AS THE WINDS DIMINISH WITH HIGH 
PRES WEAKENING N OF THE REGION. VIS SATELLITE IMAGERY REVEALS 
BROKEN TO OVERCAST STRATOCUMULUS CLOUDS COVERING MOST OF THE 
AREA N OF 20N. MODERATE TO FRESH WINDS OF ABOUT 20 KT ARE 
BLOWING ALONG THE GULF OF CALIFORNIA MAINLY N 25N DUE TO A 
STRONG LOW PRES SYSTEM PRESENTLY OVER THE SW U.S.. THESE WINDS 
ARE FORECAST TO DIMINISH IN ABOUT 24 HOURS OR SO.  

ALOFT...AN UPPER-LEVEL TROUGH PERSISTS OVER N WATERS EXTENDING 
FROM 30N120W TO 27N140W. THIS TROUGH WILL BE REINFORCED BY A  
STRONG UPPER-LEVEL LOW MOVING EWD N OF THE AREA ON SUN. THE 
ATTENDANT COLD FRONT WILL ENTER THE NW CORNER OF THE FORECAST 
AREA EARLY SUN. LONG PERIOD NW SWELL BEHIND THE FRONT IN THE 10 
TO 15 FT RANGE WILL INVADE THE AREA DURING THE DAY...ACCOMPANIED 
BY ISOLATED SHOWERS ALONG THE FRONT.  

GOES-W SATELLITE IMAGERY SHOWS A LARGE AREA OF MID/UPPER LEVEL 
MOISTURE...COINCIDENT WITH THE SUBTROPICAL JET EXTENDING FROM 
THE CENTRAL BAJA PENINSULA NEAR 27N TO 18N127W...THEN TURNING 
MORE W TO 18N140W. A BROAD UPPER-LEVEL RIDGE ANCHORED BY A HIGH 
LOCATED OVER THE GULF OF TEHUANTEPEC DOMINATES THE AREA S OF 20N 
WEST OF 105W...INCLUDING ALSO SE MEXICO...THE BAY OF CAMPECHE 
AND N CENTRAL AMERICA. MODERATE TO STRONG UPPER LEVEL SUBSIDENCE 
AND IMPLIED DRY AIR MASS IS NOTED WITHIN THE RIDGE AXIS. 

$$
GR