000
AXPZ20 KNHC 181526
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT APR 18 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...06N77W TO 
06N105W TO 07N120W TO 06N140W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION IS WITHIN 60 NM EITHER SIDE OF ITCZ FROM 119W 
TO 125W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER 
SIDE OF THE ITCZ FROM 127W TO 131W AND WEST OF 134W.

...DISCUSSION...
UPPER LEVELS...
MODERATE WESTERLIES ARE FROM 15N TO 15N WITH A PATTERN SOUTH OF 
15N AND NORTH OF 25N. A WEAK ANTICYCLONIC FLOW IS CENTERED NEAR 
33N128W AND THIS SYSTEM IS FORECAST TO MOVE EAST TO OVER 
CALIFORNIA SUNDAY AND THEN DRIFT SLOWLY EAST OVER THE WESTERN 
UNITED STATES FOR THE NEXT SEVERAL DAYS. THE WEAK PATTERN SOUTH 
OF 15N WILL SLOWLY GIVE WAY TO A BROAD HIGH PRESSURE DURING THE 
NEXT SEVERAL DAYS. A STRONG SHORTWAVE TROUGH WILL APPROACH THE 
NORTHWEST PART OF THE AREA BUT REMAIN WEST OF THE AREA THROUGH 
MID WEEK WITH INCREASING SOUTHWESTERLY DEEP LAYER FLOW OVER THE 
NORTHWEST PART BY MID WEEK. NOT MUCH WEATHER IS ASSOCIATED WITH 
THE SYSTEMS OVER THE AREA. MOIST DEEP LAYER FLOW IS OVER CENTRAL 
MEXICO WITH BROKEN TO OVERCAST MULTI LEVEL CLOUDS BETWEEN 19N 
AND 25N OVER MEXICO. OVERCAST STRATOCUMULUS IS NORTH OF 15N WEST 
OF 120W.

SURFACE...
MODERATE WINDS NORTH OF 15N WEST OF 115W, ELSEWHERE BROAD TROUGH 
IS ANALYZED. 

GAP WINDS IN THE GULF OF PAPAGAYO OF EAST AT 20 KNOTS WILL 
CONTINUE THROUGH THE NEXT COUPLE OF DAYS. 

GAP NORTHERLY WINDS OF 20 KNOTS IN THE GULF OF PANAMA REGION 
WILL CONTINUE THROUGH A COUPLE OF DAYS THEN DIMINISH BY EARLY 
MONDAY.

$$
LL