000
AXPZ20 KNHC 111514
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED MAR 11 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...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...09N83W TO 
01N105W TO 03N140W. THERE IS NO SIGNIFICANT CONVECTION ALONG THE 
ITCZ.

...DISCUSSION...

DEEP LAYER TROUGH IS OVER THE PACIFIC OCEAN AREA NORTH OF 20N 
WEST OF ABOUT 105W. THIS FEATURE WILL WEAKEN SLOWLY AND GIVE WAY 
TO A WEAK RIDGE OVER THIS AREA BY FRIDAY. A SHORTWAVE NORTH OF 
30N WEST OF CALIFORNIA WILL STRENGTHEN SOME AND MOVE OVER NORTH 
BAJA CALIFORNIA AND SOUTH CALIFORNIA THURSDAY AND CONTINUE 
ACROSS THE SOUTHWESTERN UNITED STATES AND NORTHERN MEXICO 
FRIDAY. ASSOCIATED WITH THE TROUGH IS A PLUME OF MIDDLE AND 
UPPER LEVEL MOISTURE WITH BROKEN TO OVERCAST MULTI LEVEL CLOUDS 
WITH SOME EMBEDDED RAIN AND A FEW ISOLATED CONVECTIVE CELLS IN 
THE MOUNTAINOUS REGION OF MEXICO WITHIN ABOUT 300 NM EITHER SIDE 
OF A LINE FROM 20N105W TO BEYOND 32N98W. THIS MOISTURE IS 
ADVECTING NORTHWARD ACROSS MEXICO AND OVER THE SOUTHERN GREAT 
PLAINS OF THE UNITED STATES. NORTH OF 22N WEST OF THIS MOISTURE 
PLUME TO 120W THE MIDDLE AND UPPER LEVELS ARE DRY AND CLOUD 
FREE. THE LOWER LEVELS IN THE AREA WEST OF 115W NORTH OF 22N ARE 
COVERED IN OVERCAST TO BROKEN STRATOCUMULUS CLOUDS.

AN ACTIVE TROUGH TO THE WEST OF THE AREA IS SPREADING A PLUME OF 
MIDDLE AND UPPER LEVEL MOISTURE WITH MULTI LEVEL BROKEN TO 
OVERCAST CLOUDS OVER THE AREA NORTH OF 18N WEST OF 132W.

ELSEWHERE BROAD RIDGE COVERS THE AREA IN THE MIDDLE AND UPPER 
LEVELS. THE AREA SOUTH AND EAST OF A LINE FROM 25N97W TO 15N100W 
TO 15N130W TO 10N130W TO 10N135W TO 00N138W IS DRY AND CLOUD 
FREE IN THE MIDDLE AND UPPER LEVELS. THIS AREA IS ALSO MOSTLY 
CLEAR IN THE LOWER LEVELS EXCEPT FOR SOME ISOLATED CONVECTION 
NEAR THE ITCZ.

MODERATE SURFACE RIDGE IS NORTH OF 10N W OF 102W. THIS FEATURE 
IS FORECAST TO WEAKEN SOME AS LOW PRESSURE DEVELOPS WEST OF 
140W. ELSEWHERE A BROAD TROUGH IS ANALYZED AT THE SURFACE.

GAP NORTHEASTERLY WINDS IN AND DOWNSTREAM FROM THE GULF OF 
PAPAGAYO WILL CONTINUE FOR THE NEXT SEVERAL DAYS IN THE 20 TO 25 
KNOT RANGE MOSTLY EAST OF 91W.
 
GAP NORTHERLY WINDS IN THE GULF OF PANAMA REGION OF 20 KNOTS 
WILL CONTINUE TODAY THEN DIMINISH THURSDAY TO LESS THAN 20 KNOTS.

$$
LL