000
AXPZ20 KNHC 081524
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN MAY 08 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 ALONG 07N78W TO 
07N95W TO 06N115W TO 07N126W TO 05N140W. SCATTERED MODERATE TO 
STRONG CONVECTION IS WITHIN 80 NM S OF AXIS E OF 81W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF 
AXIS FROM 85W TO 95W...WITHIN 90 NM EITHER SIDE OF AXIS BETWEEN 
112W AND 119W...AND WITHIN 90-120 NM OF AXIS BETWEEN 130W AND 
136W. A CLUSTER OF MODERATE TO STRONG CONVECTION IS NOTED ALONG 
THE COAST OF COLOMBIA AND PANAMA FROM 6N TO 8N. A DIFFLUENT 
PATTERN ALOFT IS HELPING TO MAINTAIN THIS CONVECTIVE ACTIVITY.

...DISCUSSION...

AN UPPER-LEVEL ANTICYCLONE WITH AN ASSOCIATED 1029 MB SURFACE 
HIGH REMAIN STACKED N OF HAWAII NEAR 36N153W...TO THE WEST OF A 
SHARP UPPER TROUGH AND ASSOCIATED COLD FRONT DIGGING INTO THE 
U.S. WEST COAST. AN UPPER-LEVEL TROUGH IS OVER THE NW CORNER OF 
THE AREA AND STRETCHES FROM 30N124W TO A CUT-OFF LOW CENTERED 
NEAR 25N138W. TO THE SE OF THIS TROUGH/LOW...W TO SW FLOW ALOFT 
DOMINATES MOST OF THE FORECAST WATERS N OF 10N AND W OF 105W. 
THESE WINDS ARE TRANSPORTING ABUNDANT MID TO UPPER LEVEL 
MOISTURE INTO N-CENTRAL MEXICO. UPPER LEVEL DIVERGENCE BETWEEN 
AN UPPER TROUGH THAT EXTENDS FROM 12N110W TO 01N100W AND AN 
UPPER ANTICYCLONE OVER THE SW CARIBBEAN IS ENHANCING MODERATE TO 
STRONG CONVECTION ALONG THE ITCZ BETWEEN 85W AND 95W.

FEW SHIP OBSERVATIONS AND THE MOST RECENT ASCAT PASS SHOW FRESH 
TRADE WINDS BETWEEN THE 1029 MB HIGH PRES CENTER N OF HAWAII... 
AND A WEAK SURFACE TROUGH ALONG THE ITCZ NEAR 125W FROM 3N-11N. 
IN ADDITION...WINDS OFF THE BAJA CALIFORNIA COAST ARE REACHING 
20 KT BETWEEN THE HIGH PRES OVER THE PACIFIC AND 1003 MB LOW 
PRES LOCATED OVER N CENTRAL MEXICO. THIS WEATHER PATTERN IS 
FORECAST TO PERSIST OVER THE NEXT COUPLE OF DAYS...BUT THE 
AERIAL EXTENT OF THE TRADES WILL DECREASE. FURTHER SOUTH...A 
PAIR OF WEAK LOW AMPLITUDE TROUGHS ARE NOTED ALONG THE ITCZ NEAR 
97W AND 107W DRIFTING WWD. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION CAN BE FOUND E OF THE EASTERNMOST THOUGH AXIS WITH 
ONLY A FEW SHOWERS W OF TROUGH. 

GULF OF CALIFORNIA...THERE IS LESS MODEL CONSENSUS THAN EARLIER 
CONCERNING THE LIKELIHOOD FOR 20 KT WINDS OVER THE NORTHERN GULF 
OF CALIFORNIA. THE GFS STILL SHOWS FRESH TO STRONG WESTERLY FLOW 
N OF 29N BY TONIGHT AS A TROUGH DIGS INTO THE SW UNITED 
STATES...BUT IS SHOWING THE WINDS AS MORE OF A TEMPORARY PULSE 
DURING THE OVERNIGHT TONIGHT AND MON NIGHT. 

GULF OF PAPAGAYO...SIMILAR TO THE GULF OF CALIFORNIA...SOME 
QUICK OVERNIGHT PULSES TO 20 KT ARE POSSIBLE OVER THE NEXT 48 
HOURS. A COUPLE OF SHIP OBSERVATIONS REPORTED SUSTAINED WINDS OF 
20 KT THIS MORNING.

$$
GR