** Cloud data analytics firm Snowflake's SNOW.N shares fall 1.7% to $221.18
** The Information reports co is in talks to buy app monitoring startup Observe for $1 bln
** Deal expected to be biggest for SNOW - report
** Observe's tools help detect and resolve issues in app systems
** Including session's moves, SNOW up 43.5% YTD
(Reporting by Utkarsh Tushar Hathi)
((utkarshtushar.hathi@thomsonreuters.com))