000
AXPZ20 KNHC 171503
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU APR 17 2008

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 
1200 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 01N80W 03N95W 11N110W 03N140W. 
NUMEROUS MODERATE TO STRONG CONVECTION FROM 10N-13N BETWEEN
102W-109W. SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 
10N-13N BETWEEN 116W-127W.

...DISCUSSION...
MID TO UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC CIRCULATION 
NEAR 32N134 TO ANOTHER CYCLONIC CIRCULATION NEAR 26N137W. THE 
TROUGH HAS BEEN STATIONARY THE PAST FEW DAYS TO A BLOCKING RIDGE 
ALONG THE CALIFORNIA COAST. THE RIDGE EXTENDS FROM AN 
ANTICYCLONIC CIRCULATION NEAR THE SAN FRANCISCO BAY AREA S TO 
32N123W TO 25N120W. DEEP LAYER TROUGH EXTENDS FROM CYCLONIC 
CIRCULATION OVER THE SOUTHERN ROCKIES THEN INTO NORTHERN MEXICO. 
A 90-100 KT JET AT THE BASE OF THE TROUGH ACROSS NORTHERN MEXICO.

AN UPPER LEVEL TROUGH IN THE DEEP TROPICS WITH AXIS FROM 17N137W 
10N129W TO 3N115W. E OF THE TROUGH AN UPPER LEVEL RIDGE EXTENDS
ALONG 15N TO CENTRAL AMERICA. UPPER LEVEL DIVERGENCE IS ENHANCING
CONVECTIVE ACTIVITY JUST N OF THE ITCZ FROM 10N-13N BETWEEN
102W-109W. MODERATE TO STRONG SUBSIDENCE OVER THE E PORTION OF
THE DISCUSSION AREA E OF 100W. WITH THE EXCEPTION OF ISOLATED
CONVECTIVE ACTIVITY ALONG THE ITCZ AND ALONG THE CARIBBEAN COAST
OF COSTA RICA AND PANAMA SKIES ARE MOSTLY CLEAR ACROSS THE AREA.

SURFACE RIDGING COVERS THE AREA N OF 15N W OF 107W. BROKEN TO
OVERCAST STRATOCUMULUS CLOUDS N OF 15N W OF 125W.

$$
DGS