000
AXPZ20 KNHC 152142
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 15 2011

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS FROM 05N77W TO LOW PRES 1009 
MB NEAR 04N91W TO 02N110W TO 00N124W. SCATTERED MODERATE IS S OF 
02N FROM FROM 87W TO 90W. SIMILAR CONVECTION IS NEAR 06N90W AND 
NEAR 03N94W.

...DISCUSSION...
A RIDGE/TROUGH/RIDGE PATTERN IS STILL NOTED OVER THE N WATERS.
WATER VAPOR IMAGERY INDICATES MODERATE TO STRONG SUBSIDENCE N OF 
20N W OF 120W...AND N OF 24N E OF 120W. A SHORT-WAVE TROUGH IS 
NEAR 120W N OF 20W. ANOTHER UPPER LEVEL TROUGH EXTENDS FROM THE 
SOUTHERN TIP OF BAJA CALIFORNIA TO NEAR 10N105W. ABUNDANT MID TO 
UPPER LEVEL MOISTURE IS BEEN TRANSPORTED BY A 30 TO 45 KT SWLY 
FLOW FROM ACROSS THE SOUTHERN TIP OF BAJA AND INTO N-CENTRAL 
MEXICO. AN UPPER-LEVEL RIDGE DOMINATES THE AREA E OF 100W 
INCLUDING SE MEXICO AND CENTRAL AMERICA. UPPER DIFFLUENCE 
ASSOCIATED WITH THIS FEATURE WILL PROMOTE THE DEVELOPING OF 
SHOWER AND TSTMS ACTIVITY AROUND OR NEAR THE LOW PRES SITUATED 
AT 04N91W.    

IN THE DEEP TROPICS AN ANTICYCLONIC CIRCULATION IS LOCATED NEAR 
7N124W. A DIFFLUENT PATTERN ALOFT ON THE EAST SIDE OF THIS 
ANTICYCLONE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ AND 
NEAR A SURFACE TROUGH THAT EXTENDS FROM 8N115W TO 12N118W. 

DISORGANIZED SHOWERS AND ISOLATED TSTMS REMAIN ASSOCIATED WITH A 
WEAK AREA OF LOW PRES LOCATED NEAR 04N91W. SOME CYCLONIC TURNING 
IS EVIDENT ON VISIBLE SATELLITE IMAGERY AND THE 1515 UTC ASCAT 
PASS INDICATED A BROAD CYCLONIC CIRCULATION. COMPUTER MODELS 
SHOW THIS SYSTEM PERSISTING FOR THE NEXT SEVERAL DAYS. EXPECT 
THE LOW TO DRIFT WNW WITH LITTLE CHANGE IN INTENSITY. THIS 
MONSOON LOW MAYBE THE FIRST SIGN OF THE TRANSITION INTO THE  
UPCOMING EPAC TROPICAL SEASON. 

SFC HIGH PRES JUST N OF THE AREA NEAR 32N131W EXTENDS A RIDGE SE 
TO AROUND 16N110W. THE COMBINATION OF THE HIGH AND A TROUGH OVER 
NW MEXICO IS RESULTING IN FRESH TO STRONG WINDS ACROSS THE GULF 
OF CALIFORNIA AND W OF THE BAJA CALIFORNIA PENINSULA. SOME SHIP 
OBSERVATIONS ALONG WITH THE 1650 ASCAT PASS VERIFIED THESE WIND 
SPEEDS. MODEL GUIDANCE INDICATES THE PRES GUIDANCE WILL RELAX 
OVER THE NEXT 24 HOURS...ALLOWING WINDS TO DROP BELOW 20 KT 
SAT.

MODERATE TO FRESH TRADE WINDS S OF THE HIGH WILL CONTINUE AS WELL
THROUGH SAT. AS THE HIGH SHIFTS FURTHER W AND WEAKENS...EXPECT 
TRADES TO STEADILY DIMINISH THROUGH SUN. THIS WILL ALLOW SEAS TO 
SUBSIDE BELOW 10 FT TONIGHT...AND APPROACH 8 FT BY SUN MORNING. 
LARGE AREA OF LONG PERIOD 17-18 SEC SW SWELL WILL SWEEP ACROSS 
THE E PACIFIC OVER THE NEXT SEVERAL DAYS.

$$
GR