Pattern Change to Usher in Cooler Weather

The summer-like weather we had this past weekend will likely be a distant memory by next weekend.  A change in the jetstream pattern will allow much cooler air from the north to spill into the northern Plains and Great Lakes likely by Friday and continue into Saturday and Sunday. 

Later this week strong winds within the jetstream will move into the Pacific Northwest.  Out ahead of it high pressure will bring us a couple nice days before an area of low pressure develops, moves just to the south and pulls down cool, canadian air once again.  It's possible that temperatures this weekend may not get out of the middle 40s.  Rain showers will be likely Thursday and then again on Friday but overnight lows could drop below freezing which would give us a chance to see any liquid precipitation possibly change over to a mix of snow and rain!