000
AXPZ20 KNHC 302134
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT APR 30 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...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 05N77W TO 
06N97W TO 07N110W TO 06N130W TO 05N140W. SCATTERED MODERATE IS 
WITHIN 90 NM S OF AXIS BETWEEN 82W AND 86W. SIMILAR CONVECTION 
IS NEAR 03N94W. SCATTERED MODERATE IS FROM 05N TO 11N BETWEEN 
109W AND 117W. THIS CONVECTIVE ACTIVITY IS MAINLY ASSOCIATED 
WITH A SURFACE TROUGH WITHIN THE ITCZ. 

...DISCUSSION...

W OF 110W...
A WELL AMPLIFIED MID TO UPPER LEVEL RIDGE IS PRESENT N OF 25N 
ALONG 139W. THE RIDGE IS MAINTAINING STRONG SURFACE HIGH PRES 
ACROSS THIS AREA. THE PRES GRADIENT BETWEEN THE RIDGE AND 
SURFACE TROUGHING ALONG THE NORTHERN BAJA CALIFORNIA AND 
CALIFORNIA COASTS IS ALLOWING FOR A TIGHT PRES GRADIENT THERE TO 
INDUCE NW WINDS OF 20 TO 25 KT N OF 23N E OF 120W TO THE COAST 
OF CALIFORNIA. THESE WINDS ARE EXPECTED TO DIMINISH OVER THE 
NEXT 24-30 HOURS AS THE RIDGE WEAKENS AND THE DEEP LAYER TROUGH 
MOVES EASTWARD. THE PRES DIFFERENCE BETWEEN THE RIDGE AND LOWER 
PRES ALONG THE ITCZ IS ALLOWING FOR NE-E 20 KT TRADES TO EXIST N 
OF 18N W OF 120W. THIS AREA OF TRADES IS FORECAST TO SHRINK SOME 
IN AREAL COVERAGE IN 24 HOURS.
 
TO THE SOUTH...A SHORTWAVE TROUGH S OF 22N BETWEEN 120W AND 130W 
IS HELPING TO INDUCE CONVECTION N OF THE ITCZ BETWEEN 121W AND 
126W. THIS SHOULD CONTINUE THROUGH THE NEXT 36 TO PERHAPS 48 
HOURS.

E OF 110W...A DIFFLUENT PATTERN ALOFT BETWEEN AN UPPER 
ANTICYCLONE NEAR 12N102W AND THE ABOVE MENTIONED SHORTWAVE 
TROUGH IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 12N109W 
TO 4N112W. CONVECTION ASSOCIATED WITH THIS TROUGH IS DESCRIBED 
IN THE ITCZ SECTION. E OF THE UPPER ANTICYCLONE...THE TAIL END 
OF DEEP LAYER TROUGH EXTENDS SW FROM WESTERN CARIBBEAN TO ACROSS 
HONDURAS AND NICARAGUA INTO THE EPAC TO NEAR 4N92W. 

GAP WINDS...
THE 2017 UTC EXPERIMENTAL ASCAT 25 KM COASTAL WINDS SHOWED WINDS 
BELOW 20 KT ACROSS THE GULF OF PANAMA. NE WINDS TO 20 KT THROUGH 
THE GULF OF PAPAGAYO WILL CONTINUE TO PULSE ON AND OFF THROUGH 
THE NEXT 48 HOURS...WITH MAIN OCCURRENCES LATE AT TONIGHT WITH 
THE AID OF OVERNIGHT DRAINAGE INFLUENCE.

GULF OF CALIFORNIA...THE PRES GRADIENT BETWEEN HIGH PRES OVER 
THE NE PACIFIC AND TROUGH OVER THE GULF OF CALIFORNIA AND NW 
MEXICO WILL RESULT IN FRESH TO STRONG NW FLOW TO BLOW ACROSS THE 
GULF N OF 25N IN ABOUT 24 HOURS AND N OF 23N IN 36 HOURS. SEAS 
WILL REMAIN BELOW 8 FT HOWEVER DUE TO FETCH LIMITATIONS.

$$
GR