The Bottom Line:
The 0z euro and GFS are STILL showing a major pattern amplification is going to occur in the 6-10 day that will result in the 1st SERIOUS cold air outbreak of the cold season. In THIS case the pattern amplification means a Ridge will develop over stern North America and a trough over Eastern CONUS. The issue is 1) where does this cold air enter the CONUS first? 2) Which areas will see the coldest temps
and 3) How long does this cold pattern last?
If the weather models are correct in the 6 to 10 day then all areas of the central and Upper the Plains and the Midwest will see a Major Frost / freeze around October 9-10.
In the SHORT TERM (10/2 - 10/3)
The national radar this morning shows our Low over southern MN. Moderate to heavy rains and some weak storms cover portions of eastern ND and eastern SD into central MN and northwest IA. Heavier areas of rain cover northern WI into Northern MI ... then into all of central and eastern OH northwest PA... then into eastern KY... and light weak showers are found over eastern TN into northwest GA...into central AL and far eastern LA.
The Morning weather map has the Low over Minneapolis with this cold front running from the Low to Chicago then south into western IND western KY western TN into MS and LA.
There is not much to change in the short term forecast as this Low will be the central feature over the Midwest this weekend. The Plains looks seasonal and dry. A New Low enters the Pacific NW Sunday.
In the MEDIUM RANGE (10/4 -10/6)....
That new Low over the Pacific NW is the next weather system to watch. This system means business for the western US bringing widespread significant rains and much below normal temperatures and even some snow at the very high elevations. By Monday and Tuesday this Low will track through eastern COL then head ENE to MN IA and WI. This Low will bring the Upper Plains and WCB significant rain ... 0.25 to 1.50 50-60% coverage... depending on the track of the Low.
In the 6-10 DAY (10/7 - 10/11)...
Meanwhile over the far Eastern North Pacific and the west coast of Canada the Jet will amplify into a BIG ridge will will in turn grab the cold air building in Canada and send it hurtling south. A strong cold front will Sweep through western Canada OCT 6-7 -- the season FIRST true polar cold front -- that moves into the Northern Rockies and Upper Plains OCT 8-9.
A NEW Low will develop on this strong cold... as is often the case... over OK and KS and track northeast to MI. If this was early NOV this Low could bring heavy snow to the Upper Plains. Instead this Low will bring heavy rains strong winds to the central Plains into the the WCB OCT 8-9... with the Low over MI by the 10th. MUCH colder air will sweep into the Plains and Midwest behind this Low. and into the Plains and and Midwest
In the 11-15 DAY (10/12 - 10/16):
This big Great Lakes Low will allow the heart of the cold air in western Canada to drop south into the Rockies OCT 10 in the shape of large cold High... that will be over MT OCT 11 and over eastern COL OCT 12 . I IF the High drops into OK... IF... then a hard frost freeze will occur over all of the Lower Plains and Delta as well in this time frame.
The GFS and Euro are in general agreement here though the Models differ on the power of the trough and the amount of cold air that comes into the CONUS in the end of the 6-10 day and in the early portions of the 11-15 day. Again the model do show the cold pattern collapsing in the 12-15 day as the Pacific Jet wont stop .