000
AXPZ20 KNHC 270402
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JUN 27 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0245 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...T
MONSOON TROUGH EXTENDS FROM 20N107W TO 09N122W WHERE LOW LEVEL 
WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES SW TO 
BEYOND 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION  
CONFIRMED BY LIGHTNING DATA FROM 05N TO 12N BETWEEN 83W-116W. 
 
...DISCUSSION...
AN UPPER CYCLONE OVER THE EXTREME NW CONUS HAS AN UPPER TROUGH 
EXTENDING SW ACROSS THE NW PORTION OF THE DISCUSSION AREA FROM 
32N132W TO 28N142W. A LARGE UPPER ANTICYCLONE IS CENTERED AT 
25N115W WITH A RIDGE EXTENDING SW TO A SECOND ANTICYCLONE W OF 
THE AREA AT 16N147W. AN UPPER CYCLONE OVER THE NW GULF OF MEXICO 
AT 28N96W HAS AN UPPER TROUGH EXTENDING SW ACROSS NORTHERN OLD 
MEXICO ALONG 25N100W TO A BASE OVER THE E PACIFIC AT 17N107W. 
THESE UPPER FEATURES COMBINE TO DRY OUT THE UPPER LEVELS OF THE 
DISCUSSION AREA N OF 17N W OF 107W...AND ELSEWHERE NW OF LINE 
FROM 17N107W TO 07N140W. 

AN UPPER ANTICYCLONE OVER THE SE GULF OF MEXICO HAS A RIDGE 
EXTENDING SW ACROSS CENTRAL AMERICA TO A CREST OVER THE E 
PACIFIC AT 16N104W. THE ASSOCIATED UPPER DIFFLUENCE IS 
SUPPORTING CONVECTION OVER CENTRAL AMERICA BETWEEN 85W AND 95W.
THE RESULTANT DEBRIS MOISTURE SPREADS W OVER THE PACIFIC FROM 
12N TO 17N E OF 105W BEFORE TURING NE AROUND THE UPPER RIDGE AND 
BACK ACROSS THE CENTRAL PORTION OF OLD MEXICO AND ACROSS THE SW 
GULF OF MEXICO. FURTHER S...THE UPPER FLOW IS EASTERLY OVER THE 
DEEP TROPICAL CONVECTION PREVIOUSLY MENTIONED...AND THE DEBRIS 
MOISTURE IS ADVECTED W TO 120W WHERE IT QUICKLY EVAPORATES. 

AT THE LOW LEVELS A RIDGE EXTENDS FROM 30N140W TO NEAR 20N122W. 
NW FLOW IS ENHANCED TO 20 KT WELL NE OF THE RIDGE IN THE AREA N 
OF 26N E OF 120W TO THE BAJA CALIFORNIA PENINSULA...WITH SEAS TO 
8 FT IN THE ASSOCIATED NW SWELL. THE GRADIENT WILL WEAKEN 
TONIGHT AS THE BAJA HEAT TROUGH DISSIPATES WITH WINDS EXPECTED 
TO DIMINISH TO ABOUT 15 KT BY SUNRISE...AND THE SEAS SHOULD 
SUBSIDE TO 5 TO 6 FT BY MIDDAY WED.
  
THE UPPER TROUGH OVER THE NW PORTION WILL BE REINFORCED AND THE 
ANTICYCLONES WILL STRENGTHEN IN ROUGHLY THE SAME POSITION 
THROUGH THE END OF THE WEEK. NE TO E LOW LEVEL FLOW WILL 
INCREASE IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO FRI NIGHT AND 
SAT. WITH LOW LEVEL SW FLOW CONTINUING JUST TO THE S OF PAPAGAYO 
AREA THERE WILL LIKELY BE AN INCREASE IN LOW LEVEL CYCLONIC 
MOTION ALONG 09N BETWEEN 85W AND 95W.   

$$
NELSON