000
AXPZ20 KNHC 300914
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT APR 30 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0830 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 08N82W 
TO 03N95W TO 05N105W TO 03N120W TO 05N140W. SCATTERED MODERATE 
TO ISOLATES STRONG CONVECTION IS NOTED WITHIN 120 NM N OF 
AXIS FROM 105W TO 115W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION N OF AXIS FROM 06N TO 10N BETWEEN 122W AND 132W.

...DISCUSSION...
W OF 110W...A WELL AMPLIFIED MID TO UPPER LEVEL RIDGE EXTENDS N 
OF 25N ALONG 140W...AHEAD OF DEEP LAYER TROUGH MOVING TO THE N 
OF THE HAWAIIAN ISLANDS. THE RIDGE IS SUPPORTING A 1037 MB 
SURFACE HIGH NEAR 39N135W. NW WINDS OF 20 TO 25 KT PERSIST ALONG 
THE BAJA COAST BETWEEN THE HIGH PRES AND A SURFACE TROUGH ALONG 
THE GULF OF CALIFORNIA. PERSISTENT 20 TO 25 KT NE TRADE WINDS 
ARE ALSO EVIDENT S OF THE SURFACE RIDGE...MAINLY N OF 18N. 
NORTHERLY SWELL UP TO 13 FT WILL PUSH S OF 30N OFF THE BAJA 
COAST LATER TODAY...WITH SEAS OF 8 TO 9 FT THROUGHOUT THE AREA 
OF FRESH TO STRONG TRADES. THE SURFACE HIGH PRES WILL WEAKEN AND 
SHIFT SOUTH AS THE UPPER TROUGH PROGRESSES EASTWARD. THIS WILL 
ALLOW THE STRONG WINDS OFF BAJA TO DIMINISH THROUGH LATE 
SUN...LEAVING MODERATE TO FRESH TRADES OVER MOST OF THE AREA W 
OF 125W. FURTHER SOUTH...AN UPPER LEVEL SHORT WAVE TROUGH S 
OF 20N BETWEEN 120W AND 130W ARE IN PHASE WITH MODERATE TRADE 
WIND CONVERGENCE SUPPORTING CLUSTERS OF CONVECTION ALONG THE 
ITCZ BETWEEN 120W AND 130W. 

E OF 110W...DIVERGENCE ALOFT BETWEEN AN UPPER ANTICYCLONE NEAR 
13N105W AND AN UPPER SHORT WAVE TROUGH ALONG 110W IS SUPPORTING 
A PERSISTENT AND QUASI-STATIONARY SURFACE TROUGH ALONG 105W FROM 
04N TO 10N...ALONG WITH ASSOCIATED SCATTERED CLUSTERS OF 
MODERATE STRONG CONVECTION. FURTHER EAST...N FLOW TO 20 KT WILL 
PUSH FROM THE SW CARIBBEAN THROUGH THE ISTHMUS OF PANAMA INTO 
THE GULF OF PANAMA LATER TODAY...BUT DIMINISH QUICKLY AS 
GRADIENT FLOW OVER THE SW CARIBBEAN ABATES. SIMILARLY GAP WIND 
FLOW THROUGH THE GULF OF PAPAGAYO WILL PULSE BRIEFLY THIS 
MORNING...AND AGAIN LATE TONIGHT WITH THE AID OF OVERNIGHT 
DRAINAGE INFLUENCE.

GULF OF CALIFORNIA...THE GRADIENT BETWEEN HIGH PRES OVER THE NE 
PACIFIC AND TROUGH OVER THE GULF OF CALIFORNIA AND NW MEXICO 
WILL ALLOW FRESH W TO NW FLOW TO COVER THE FAR NORTHERN GULF. 
SEAS WILL REMAIN BELOW 8 FT HOWEVER DUE TO FETCH LIMITATIONS.

$$
CHRISTENSEN