000
AXPZ20 KNHC 211509
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE APR 21 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...
AXIS ALONG 7N81W 4N95W 5N110W 6N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WITHIN 120 NM S OF AXIS BETWEEN 86W 
AND 94W. 

...DISCUSSION...
A BROAD MIDDLE TO UPPER LEVEL RIDGE OVER THE NW PORTION OF THE 
AREA N OF 25N W OF AROUND 125W. DOWN STREAM MID/UPPER LEVEL 
TROUGH OFF THE SOUTHERN CALIFORNIA COAST EXTENDS FROM A CYCLONIC 
CIRCULATION NEAR 32N122W SE TO 27N118W. SOME HIGH LEVEL MOISTURE 
IS MOVING NE OF THE TROUGH INTO SOUTHERN CALIFORNIA. UPPER LEVEL 
RIDGE WITH AXIS FROM SE ARIZONA TO SOUTHERN TIP OF BAJA 
CALIFORNIA THE EQUATOR AT 105W. AN 80-95 KT JET STREAM EXTENDS 
FROM 22N121W TO 23N110W THEN ACROSS MEXICO TO 20N97W. THE JET IS 
ADVECTING UPPER LEVEL CLOUDS FROM TROPICAL CONVECTION NE TOWARD 
SOUTHERN BAJA CALIFORNIA. A BROAD UPPER LEVEL TROUGH IS OVER 
CENTRAL AMERICA. STRONG SUBSIDENCE IS N OF THE ITCZ E OF 95W...
WITH MOSTLY DRY STABLE AIR.

HIGH PRES BEHIND A COLD FRONT IN THE GULF OF MEXICO HAS 
TIGHTENED THE GRADIENT ACROSS SOUTHERN MEXICO WITH GALE FORCE 
WINDS BLOWING THROUGH THE GULF OF TEHUANTEPEC...WHICH SHOULD 
DECREASE BY LATE TONIGHT. A SURFACE TROUGH EXTENDS FROM A 1010 
MB LOW OVER THE FAR N PORTION OF THE GULF OF CALIFORNIA S TO 
24N109W. A 1020 MB HIGH PRES IS CENTERED NEAR 26N129W WITH RIDGE 
FROM THE HIGH TO 21N120W. BROKEN TO OVERCAST STRATOCUMULUS 
CLOUDS BLANKET THE AREA N OF 20N W OF 120W.

$$
DGS