The weather pattern is just about as wild as one you will see for late October. I posted maps for the thunderstorms today in the Midwest and the potential snowfall coming midweek. The storms today will be mainly hail and high wind producers as they move through Illinois into Indiana.
The BIG Storm
Here's what I think will happen with the storm late in the weekend and into early next week.
The NAO is becoming highly negative which to me means a big storm is coming, but it's a question of when does the storm come and will the storm be Sandy or not? Typically, tropical systems will ride along the outer part of the trough which I think will be the case with Sandy. The map below shows the upper-level low coming into the Midwest with low pressure in Ohio. A cold front will extend into the South, and a warm front will be located across Virginia. Sandy will come up the coast, being whipped around the outer part of the trough. Once Sandy is out of the way, low pressure will redevelop along the coast in the classic secondary style and that will become the storm.
I do not believe the historic event shown by the Euro is correct only because tropical systems very rarely try to plow under an upper-level low like what the Euro shows.
The moonson will bring some nasty weather to the Southwestern part of the country.
Watching the system in the Gulf of Mexico for development. Probably a small chance.
Heat builds into the East while the rain continues for the Pacific Northwest.
Erika will have many issues this weekend includng tracking over the islands with big mountains.
Erika will track into the Bahamas and may intensify early next week. Track could bring it close to the U.S.