000
AXPZ20 KNHC 050326
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN APR 05 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 
0330 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 08N83W 
TO 03N100W TO 02N120W TO O4N135W TO 03N140W. NO SIGNIFICANT 
CONVECTION.

...DISCUSSION...
A WEAK MID/UPPER LEVEL TROUGH PERSISTS OVER THE NW CORNER OF THE 
AREA WITH STRONG SUBSIDENCE NOTED N OF 23N W OF 125W. THIS 
TROUGH WILL BE REINFORCED BY A DEVELOPING MID/UPPER LEVEL LOW 
NEAR 41N135W DIVING SE AT AROUND 20 KT. THE UPPER-LEVEL LOW WILL 
CONTINUE MOVING SOUTHEASTWARD THEN EASTWARD TOWARDS CALIFORNIA 
OVER THE NEXT FEW DAYS. AT THE SURFACE...THE ATTENDANT COLD 
FRONT IS CURRENTLY APPROACHING 30N140W AND WILL MOVE INTO NW 
WATERS AROUND 0600 UTC WITH NW SWELL OF UP TO 15 FT MOVING IN 
BEHIND THE FRONT LATE SUN INTO MON. ALSO...EXPECT ISOLATED 
SHOWERS ALONG THE FRONTAL BOUNDARY. 

THE AFOREMENTIONED COLD FRONT WILL WEAKEN THE SURFACE RIDGE IN 
PLACE EXTENDING FROM 30N125W TO 15N110W. AT THE SAME TIME...A 
WEAK 1020 MB SFC HIGH LOCATED N OF AREA NEAR 33N127W WILL MOVE 
SE ENTERING THE NE WATERS OVER THE NEXT 24 HOURS. UNDER THIS 
WEATHER PATTERN...THE TRADE WINDS WILL CONTINUE TO DIMINISH 
BELOW 20 KT IN ABOUT 24 TO 36 HOURS...AND THE NW SWELL OFF THE 
BAJA CALIFORNIA PENINSULA WILL CONTINUE TO SUBSIDE. 

SOUTH OF THE WEAK MID/UPPER LEVEL TROUGH THERE IS A LARGE AREA 
OF MID/UPPER LEVEL MOISTURE...COINCIDENT WITH THE SUBTROPICAL 
JET EXTENDING FROM THE CENTRAL BAJA CALIFORNIA PENINSULA TO 
20N130W...THEN TURNING MORE W TO 20N140W. A BROAD UPPER-LEVEL 
RIDGE DOMINATES THE AREA S OF 20N WEST OF 110W...INCLUDING ALSO 
SE MEXICO...THE BAY OF CAMPECHE AND N CENTRAL AMERICA WHERE 
MOSTLY FAIR WEATHER PREVAILS DUE TO STRONG SUBSIDENCE ALOFT. AN 
UPPER LEVEL TROUGH/SHEAR AXIS LIES WEST OF THE RIDGE ALONG 
114W/115W.  

WINDS OVER THE GULF OF CALIFORNIA HAVE DIMINISHED BELOW 20 
KT...BUT WILL ONCE AGAIN BRIEFLY REACH 20 KT SUN AFTERNOON 
THROUGH MON MORNING AS THE SW CONUS COLD FRONT FINALLY WORKS ITS 
WAY SOUTHWARD INTO NW MEXICO AND NORTHERN GULF OF CALIFORNIA.

LOOKING AHEAD...A LATE SEASON GULF OF TEHUANTEPEC GALE EVENT IS 
FORECAST BEGINNING EARLY TUE AS A HIGH PRES BUILDS SWD ALONG THE 
EASTERN SLOPES OF THE SIERRA MADRE MOUNTAINS OF MEXICO IN THE 
WAKE OF A STRONG COLD FRONT EXPECTED TO MOVE OFF THE TEXAS COAST 
SUNDAY AFTERNOON. IT IS NOT OUT OF QUESTION THAT THIS EVENT MAY 
REACH STORM FORCE WINDS. ON AVERAGE...THE LAST TEHUANTEPEC EVENT 
OCCURS AROUND APRIL FIRST. 

$$
GR