(undated)  --  A Northwest heat wave could shatter all-time records in Washington and Oregon.  The National Weather Service has issued excessive heat alerts from Idaho to Northern California.  The heat wave could last for several days, pushing record-breaking highs into early next week.  The Weather Channel is predicting triple-digit temperatures as far north as western Canada.  It warns Seattle could reach a rare 100 degrees on Sunday and Monday, and Portland could reach a record-breaking 110 degrees.  Salem, Eugene and Medford, Oregon could also get above 110 by Sunday.