000
AXPZ20 KNHC 042145
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE MAY 04 2010

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...
AXIS IS ALONG 07N86W TO 05N88W TO 06N104W TO 03N121W TO 06N140W. 
SCATTERED MODERATE CONVECTION WITHIN 120 NM OF AXIS E OF 106W.  
ISOLATED MODERATE CONVECTION WITHIN 60 NM OF AXIS W OF 114W.

...DISCUSSION...
SHARP UPPER LEVEL TROUGH EXTEND FROM 32N122W TO 00N124W WITH A 
10 DEG SWATH OF DRY AIR MASS CENTERED ALONG AXIS.  UPSTREAM 
RIDGE WITH CREST ALONG 133W ADVECTING MINOR AMOUNTS OF MOISTURE 
W OF AXIS.  BROAD DOWNSTREAM ANTICYCLONE AT 21N100W PRACTICALLY 
COVERS REMAINDER OF BASIN WITH DRY STABLE AIR MASS N OF ITCZ... 
EXCEPT FOR SECOND TROUGH ALOFT EXTENDING FROM NICARAGUA TO 
04N91W.  SMALL AREA OF DIFFLUENT UPPER LEVEL FLOW JUST SE OF 
SECOND TROUGH ENHANCES DEEP ITCZ CONVECTION E OF 89W.  E-NE FLOW 
AROUND SOUTHERN PERIPHERY OF RIDGE DOES NOT FAVOR DEVELOPMENT OF 
WEAK SURFACE TROUGH EMBEDDED IN ITCZ FROM 04N107W TO 11N102W... 
ALTHOUGH CONDITIONS BECOME MORE FAVORABLE FURTHER W AS TROUGH 
APPROACHES 115W.  TROUGH PRESENTLY ASSOCIATED WITH SCATTERED 
MODERATE CONVECTION WITHIN 120 NM E OF AXIS.  

ELSEWHERE AT THE SURFACE...
WEAK DISSIPATING COLD FRONT ALONG 32N E OF 130W MAINTAIN 
MODERATE TO FRESH NORTHERLY FLOW JUST N OF 30N...BUT EXPECTED TO 
EXPAND S OF 30N E OF 130W BY THU.  MODERATE N SWELLS SPREAD S 
OF 23N.  

LARGE SURFACE RIDGE CENTERED N OF AREA IS DOMINANT FEATURE 
ACROSS E PAC N OF ITCZ.  MODEL GUIDANCE GENERIC SOLUTIONS 
MAINTAIN FRESH NE TRADES N OF 08N W OF 130W EXPANDING BY THU. 

$$
WALLY BARNES