000
AXPZ20 KNHC 070951
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE MAY 07 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N84W TO 08N107W THEN ITCZ TO 
10N110W...THEN RESUMES FROM 09N114W TO 09N127W TO 06N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM S OF
AXIS FROM 107W-112W AND WITHIN 120 NM N OF AXIS FROM 130W-137W. 

...DISCUSSION... 
BROAD UPPER LEVEL ANTICYCLONE AT 10N115W MAINTAINS STEADY FLOW
ALOFT ACROSS E PAC W OF 100W.  LARGE AMPLITUDE LONGWAVE TROUGH 
DIGS SW FROM CYCLONE OVER SE CONUS THROUGH YUCATAN PENINSULA TO
10N100W.  VERY DRY AND STABLE AIR MASS WITHIN 5 DEGREES EITHER
SIDE OF TROUGH AXIS N OF 10N.  

ANTICYCLONE SITS ABOVE SURFACE WEAK SURFACE TROUGH ALONG 112W
FROM 06N TO 13N.  MODERATE DIVERGENCE ALOFT BETWEEN TROUGH TO 
THE E AND ANTICYCLONE TO THE W ENHANCES CONVECTION WITHIN 270 NM
E OF TROUGH AXIS.  TROUGH EXPECTED TO FURTHER WEAKEN AS IT PULLS
AWAY FROM DIVERGENCE REGION AND ITS CONVECTION SUBSIDES. 

...ELSEWHERE AT THE LOWER LEVELS... 
VERY TAME MARINE CONDITIONS ACROSS ENTIRE BASIN DUE TO LARGE 
STATIONARY SURFACE HIGH PRES 1020 MB AT 24N1256W WITH RIDGE 
EXTENDING SE TO 14N110W.  RIDGE PROMPTS GENTLE TO MODERATE TRADES
ON ITS S PERIPHERY N OF ITCZ.  TRADES EXPECTED TO BECOME A FRESH
BREEZE LATE IN FORECAST PERIOD AS HIGH PRES STRENGTHENS TO 1025
MB AND TIGHTENS PRES GRADIENT AGAINST ITCZ.  

...OUTLOOK...
RIDGE STAYS STRONG ENOUGH THROUGH END OF WEEK TO DEFLECT TO THE
NE COLD FRONT APPROACHING 140W LATE THU AND A SECOND FRONT ON SAT.
  
$$
WALLY BARNES