000
AXPZ20 KNHC 022138
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU APR 02 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 ITCZ AXIS EXTENDS FROM 08N83W TO 01N100W TO 02N120W TO 
3N140W. ISOLATED MODERATE WITHIN 70 NM OF AXIS E OF 91W. 

...DISCUSSION...
ALOFT...AN UPPER-LEVEL TROUGH EXTENDS E TO W ACROSS THE NORTHERN 
PORTION OF THE FORECAST REGION WITH A CUT-OFF LOW NEAR 28N140W. 
SOUTH OF THIS TROUGH...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES 
THE REMAINDER OF THE AREA. AN UPPER LEVEL JET STREAM MAXIMUM 
STRETCHES FROM 21N120W ENE ACROSS NORTHERN MEXICO INTO THE GULF 
OF MEXICO WHERE WINDS INCREASE TO 110 KT. ABUNDANT MID/UPPER 
LEVEL MOISTURE IS NOTED ON WV IMAGERY COVERING MUCH OF THE AREA 
FROM 10N TO 25N WEST OF 120W. SUBSIDENCE AND THE ASSOCIATED DRY 
AIR MASS IS NOTED S OF 20N WEST OF 115W UNDER THE INFLUENCE OF 
RIDGE ANCHORED ON AN UPPER-LEVEL HIGH LOCATED NEAR JUST SOUTH OF 
THE GULF OF TEHUANTEPEC NEAR 14N94W. THE RIDGE ALSO ENVELOPS SE 
MEXICO AND NORTHERN CENTRAL AMERICA.  

AT THE SURFACE...A 1036 MB HIGH CENTERED NW OF DISCUSSION NEAR 
37N150W WILL SLIDE SE OVER THE NEXT 24 HOURS WHILE EXTENDING A 
RIDGE AXIS THROUGH THE AREA FROM 30N140W TO 18N110W. THE PRES 
GRADIENT BETWEEN THE RIDGE AND THE ITCZ HAS THE WINDS UP TO 20 
KT N OF THE ITCZ WEST OF 130W...AND ALSO TO 20 KT W OF THE BAJA 
PENINSULA AS THE RIDGE INTERACTS WITH THE LOW PRES TROUGH JUST E 
OF THE AREA. THE MODEL GUIDANCE INDICATES NOT MUCH CHANGE WITH 
THE PRES GRADIENT AND WINDS OVER THE NEXT DAY OR TWO...SO EXPECT 
CURRENT CONDITIONS TO PERSIST. NORTHERLY SWELL WILL CONTINUE TO 
PUSH INTO THE WATERS OFF NORTHERN BAJA PENINSULA THROUGH THE 
NEXT 48 HOURS...RANGING FROM 8 TO 13 FT. LOOKING AHEAD...A COLD 
FRONT IS FORECAST TO ENTER THE NW PORTION OF THE DISCUSSION AREA 
ON SUN. ALSO...THE TRADE WINDS ARE EXPECTED TO DIMINISH IN ABOUT 
36 TO 48 HOURS AS HIGH PRES NW OF THE AREA WEAKENS.

$$
GR