000
AXPZ20 KNHC 051523
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAY 05 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...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS CENTERED ALONG 09N84W 
TO 07N95W TO 10N106W TO 08N120W TO 03N140W. SCATTERED MODERATE 
TO STRONG CONVECTION NOTED WITHIN 90 NM S OF AXIS BETWEEN 85W 
AND 88W.  SIMILAR CONVECTION IS N OF 04N E OF 85W TO THE COAST 
OF COLOMBIA. SCATTERED MODERATE TO STRONG CONVECTION IS ALSO 
NOTED FROM 06N TO 11N BETWEEN 99W AND 102W...AND FROM 11N TO 14N 
BETWEEN 101W AND 109W. SCATTERED MODERATE IS WITHIN 90 NM S OF 
AXIS BETWEEN 102W AND 106W.

...DISCUSSION...

AN UPPER-LEVEL TROUGH IN THE WESTERLY FLOW EXTENDS FROM 18N23W 
TO A COL NEAR 9N108W. A DIFFLUENT PATTERN ALOFT BETWEEN THIS 
TROUGH AND AN UPPER ANTICYCLONE LOCATED NEAR 12N100W IS HELPING 
TO MAINTAIN MODERATE TO STRONG CONVECTION NEAR A SURFACE TROUGH 
WITHIN THE ITCZ THAT EXTENDS FROM 12N108W TO 05N109W.

A BROAD SWATH OF FRESH TRADE WINDS IS NOTED...MAINLY W OF 130W 
AND N OF THE ITCZ PER AN EARLIER ASCAT PASS. THESE WINDS ARE 
ASSOCIATED WITH A WEAKENING 1030 MB SURFACE HIGH PRES NEAR 
35N140W THAT EXTENDS A RIDGE SE OVER THE FORECAST WATERS TO NEAR 
20N120W. THESE TRADES WILL PERSIST THROUGH THE REMAINDER OF THE 
WEEK...AIDED BY THE APPROACH OF THE AFOREMENTIONED SURFACE 
TROUGH FORECAST TO MOVE WWD. 

GAP WINDS...
AN EARLIER ASCAT PASS CONFIRMED THE EXISTENCE OF 35 TO 40 KT 
WINDS THROUGH THE GULF OF TEHUANTEPEC. SINCE RECORDS BEGAN IN 
1999...THIS IS THE FIFTH GALE FORCE WIND EVENT DURING THE MONTH 
OF MAY. THE PREVIOUS ONE OCCURRED ON 19 MAY 2009. THE GALES IN 
THIS AREA ARE DUE TO ANOMALOUSLY STRONG HIGH PRES N OF THE AREA 
OVER THE WESTERN GULF OF MEXICO BEHIND A COLD FRONT...AND WILL 
DIMINISH BELOW GALE FORCE BY THIS AFTERNOON AS THE HIGH PRES 
SHIFTS EASTWARD. NE SWELLS IN ASSOCIATION WITH THIS GALE EVENT 
WILL SPREAD S AND SW...RAISING SEAS TO A RANGE OF 8-11 FT FROM 
05N TO 15N BETWEEN 92W AND 107W IN 24 HOURS. NE WINDS OF 20 KT 
AND SEAS TO 8 FT WILL LINGER FROM 11N TO 13N BETWEEN 105W AND 
116W BY SAT MORNING.

FURTHER SOUTH...ALL MAJOR GLOBAL MODELS SHOW 20 TO 25 KT WINDS 
THROUGH THE GULF OF PAPAGAYO THIS MORNING AND FRI MORNING WITH 
SEAS OF UP TO 9 FT...LIKELY DUE TO OVERNIGHT DRAINAGE EFFECTS 
AND THE TIGHTENED PRES GRADIENT BETWEEN THE HIGH PRES TO THE 
NORTH AND TROUGHING NEAR PANAMA. SHORT LIVED PULSES TO 20 KT ARE 
EXPECTED THROUGH SAT MORNING. 

$$
GR