000
AXPZ20 KNHC 070935
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT MAY 07 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 
0845 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 06N77W TO 
07N85W TO 06N95W TO 10N110W TO 05N140W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION WITHIN 120 NM N OF AXIS BETWEEN 100W 
AND 110W.

...DISCUSSION...

SHIP AND ASCAT DATA SHOW MAINLY 15 TO 20 KT TRADE WIND FLOW OVER 
MUCH OF THE AREA W OF 110W...BETWEEN A 1030 MB HIGH PRES CENTER 
N OF HAWAII...AND TWO WEAK TROUGHS ALONG THE ITCZ NEAR 137W AND 
111W. SEAS ARE ESTIMATED TO BE 6 TO 8 FT IN THIS AREA. IN 
ADDITION...WINDS OFF THE CENTRAL AND SOUTHERN BAJA COAST ARE 
REACHING 20 KT BETWEEN THE HIGH PRES OVER THE PACIFIC AND 1002 
MB LOW PRES OVER N CENTRAL MEXICO. THE NW FLOW OFF BAJA WILL 
PERSIST ALONG THE ENTIRE BAJA COAST THROUGH AT LEAST MON AS A 
TROUGH DIGS OVER THE SW UNITED STATES. ELSEWHERE W OF 110W TRADE 
WINDS WILL GRADUALLY DIMINISH BELOW 20 KT AS TROUGHING ALONG THE 
ITCZ DAMPENS OUT. 

AN UPPER TROUGH EXTENDS FROM 19N125W TO 02N110W. BROAD UPPER 
DIVERGENCE BETWEEN THE TROUGH AND AN UPPER RIDGE EXTENDING FROM 
NORTHERN CENTRAL AMERICA TO 07N105W IS MAINTAIN A 
QUASI-STATIONARY SURFACE TROUGH EXTENDING FROM 15N111W TO 
07N110W...WHICH IS WELL DEFINED ON A 05Z ASCAT PASS. TOGETHER 
WITH LOW LEVEL CONVERGENCE...THE UPPER DIVERGENCE IS ALSO 
ENHANCING CLUSTERS OF MODERATE TO STRONG CONVECTION TO THE NORTH 
OF THE ITCZ BETWEEN 90W AND 110W. 

GAP WINDS...
A SURFACE TROUGH OVER THE YUCATAN PENINSULA IS RESULTING IN 
RESIDUAL FUNNELING WINDS THROUGH THE GULF OF TEHUANTEPEC...AS 
SHOWN BY A 03Z ASCAT PASS. THESE WINDS WILL DIMINISH BELOW 20 KT 
THROUGH MIDDAY TODAY AS THE GRADIENT TO THE NORTH LOOSENS. 

FURTHER SOUTH...THE SAME ASCAT PASS SHOWED 20 TO 25 KT WINDS 
PERSISTING THROUGH THE GULF OF PAPAGAYO. THIS IS INTERESTING 
SINCE THE USUAL MECHANISMS FOR GAP FLOW THROUGH PAPAGAYO ARE NOT 
PRESENT...NAMELY STRONGER TRADES OVER THE SW CARIBBEAN AND/OR 
GOOD OVERNIGHT DRAINAGE CONDITIONS DUE TO RADIATIONAL COOLING. 
THE 03Z ASCAT MAY PROVIDE A CLUE...SHOWING A WEAK CYCLONIC 
CENTER S OF COSTA RICA NEAR 07N84W. WIND REPORTS FROM NEARBY 
SHIP OBSERVATIONS ARE INCONCLUSIVE...BUT PRESSURE READINGS HINT 
OF LOWER PRESSURE IN THE AREA. IF THIS LOW IS PRESENT IT WOULD 
EXPLAIN THE ENHANCED FLOW THROUGH PAPAGAYO. 

A SHIP REPORTED 25 KT N FLOW THROUGH THE GULF OF PANAMA. WHILE 
THIS MAY BE A LITTLE HIGH...IT DOES HINT OF FRESH TRADE WIND 
FLOW OFF THE CARIBBEAN COAST OF COLOMBIA IS PUSHING ACROSS 
EASTERN AND CENTRAL PANAMA INTO THE GULF OF PANAMA. 

GULF OF CALIFORNIA...
WESTERLY FLOW OVER THE NORTHERN GULF OF 
CALIFORNIA WILL INCREASE TO 20 KT BY LATE SUN...BETWEEN HIGH 
PRES OVER THE EASTERN PACIFIC AND DEEP LAYER LOW PRES DIGGING 
THROUGH THE SW UNITED STATES. SEAS WILL REMAIN BELOW 8 FT DUE TO 
LIMITED FETCH IN THAT AREA. 

$$
CHRISTENSEN