000
AXPZ20 KNHC 120939
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON MAY 12 2008

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 
0900 UTC.

...ITCZ...
ITCZ AXIS ALONG 05N77W TO 04N85W TO 06N97W TO 04N104W TO 08N121W 
TO 04N136W TO 05N140W.  SCATTERED MODERATE CONVECTION WITHIN 60 
NM OF 05N131W.

...DISCUSSION...
MID/UPPER LEVEL TROUGH FROM 32N123W TO 23N129W MAINTAINS 
CYCLONIC FLOW N OF 20N W OF 120W.  DRY AIR MASS UNDER TROUGH 
FLOW DUE TO STRONG SUBSIDENCE.  WEAK JET STREAM ENTERING BASIN 
NEAR 17N140W BRINGING IN SUBSTANTIAL AMOUNTS OF TRPCL MOISTURE. 
BROAD RIDGE S OF 20N W OF 115W BLOCKS ANY SIGNIFICANT SOUTHWARD 
INTRUSION OF TROUGH.  SECOND ANTICYCLONE OVER BAY OF CAMPECHE 
EXTENDS WESTWARD TO 100W ALLOWING MOISTURE FROM SOUTH AMERICAN 
CONTINENT TO DRIFT OVER E PAC AROUND ITS SRN PERIPHERY.  
MOISTURE IS THEN BROUGHT N AND NE BY WEAK ANTICYCLONIC FLOW.
MODERATE DIVERGENT FLOW DUE TO DEFORMATION ZONE BETWEEN THE TWO 
RIDGES ENHANCING SCATTERED MODERATE DEEP CONVECTION NEAR 100W 
JUST AHEAD OF WEAK SURFACE TROUGH IN VICINITY.  

AT THE SURFACE...
HIGH PRES 1026 MB AT 33N145W HAS RIDGE EXTEND TO 13N108W CAUSING 
LONG FETCH STRONG NLY WIND TO BUILD LARGE SWELLS ENCROACHING 
ACROSS NRN BORDER OF BASIN FROM 118W-126W THROUGH NEXT 48 HRS. 
FRESH NE TRADES FROM 10N-20N W OF 125W EXPECTED TO CONTINUE NEXT 
48 HRS.

WEAK TROUGH NOW ALONG 97W HAS FAVORABLE ENVIRON ALOFT AND SHOULD 
MAINTAIN ITS CONVECTION GOING FOR NEXT 36-48 HRS BEFORE IT 
ENTERS ADVERSE CONDITIONS.

$$
WALLY BARNES