000
AXPZ20 KNHC 171507
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN APR 17 2011

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 IS ALONG 10N86W 10N110W 5N125W 3N135W. NUMEROUS MODERATE TO 
STRONG CONVECTION FROM 02N-5N BETWEEN 132W-138W.

...DISCUSSION...
UPPER LEVEL TROUGH IS OVER THE FAR NW PORTION OF THE DISCUSSION 
FROM 32N128W TO 22N148W. DOWNSTREAM A FLAT UPPER LEVEL RIDGE 
WITH AXIS FROM 30N125W TO AN ANTICYCLONIC CIRCULATION NEAR 
21N127W. UPPER LEVEL TROUGH EXTEND FROM NORTHERN BAJA CALIFORNIA 
TO 17N120W. MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR AT 
THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE IS FROM 16N-30N 
BETWEEN 115W-130W.

IN THE DEEP TROPICS AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS 
CENTERED NEAR 5N124NW WITH RIDGE FROM THE ANTICYLONE TO 18N130W. 
UPPER LEVEL DIFFLUENT FLOW BETWEEN THE ANTICYCLONIC CIRCULATION 
AND A TROUGH W OF THE DISCUSSION AREA IS ENHANCING CONVECTIVE 
ACTIVITY NEAR A SURFACE LOW NEAR 3N136W. AN UPPER LEVEL RIDGE 
EXTENDS FROM AN UPPER LEVEL ANTICYCLONIC CIRCULATION OVER 
COLOMBIA THROUGH PANAMA TO 15N99W THE FLATTENS OVER CENTRAL 
MEXICO.

SURFACE RIDGE COVERS THE AREA N OF 15N W OF 120W. THE PRES 
GRADIENT AROUND THE PERIPHERY OF THE RIDGE HAS WEAKENED AND ELY 
WINDS HAVE DECREASED TO BELOW 20 KT...WITH SOME SWELL UP TO 9 FT 
S OF 20 W OF 120W. WEAK SURFACE TROUGH OFF THE COAST OF MEXICO  
EXTENDS FROM 19N107W TO 16N105W. NO SIGNIFICANT WEATHER 
ASSOCIATED WITH THE TROUGH. A 1010 MB SURFACE LOW IS ANALYZED 
ALONG THE ITCZ NEAR 8N94W. ISOLATED SHOWERS ARE NEAR THE LOW. 
A TROUGH IS ALSO ANALYZED ALONG THE ITCZ FROM 10N120W TO 4N124W 
SCATTERED SHOWERS AND ISOLATED TSTMS ARE FROM 5N-8N BETWEEN 
120W-126W. A 1008 MB LOW PRES IS CENTERED NEAR 3N136W. NUMEROUS 
MODERATE TO STRONG CONVECTION IS FROM 2N-5N BETWEEN 132W-138W.

$$
DGS