Friday, 11:55 a.m.
Today's post will be brief, but it will be solely on the upcoming change for next week. The hype is out there now about the 'polar vortex' that's coming for next week. While it is going to mean an impressive cool down for the middle of summer, just about coinciding with the typical peak of summer heat, let's really see how this measures up before we buy into all of the hype!
What is it really? An upper-level low pressure area, plain and simple. The 12z July 11 NAM 500mb forecast shows it very nicely approaching the Upper Midwest and Dakotas:
It's really two separate features, with the whole thing really being one elongated upper-level low stretching from North Dakota and northwestern Minnesota Monday morning to east of James Bay. The 0z July 11 GFS forecast for Tuesday morning has it becoming more consolidated over the Great Lakes:
For any month of the year, that feature would be impressive! It represents a pocket of chilly air aloft, and it will translate into an uncommonly cool and dry air mass getting pushed unusually far south for this time of the year. The actual cold front will get deep into the South and off the East coast in time, and the indications are quite strong that record lows are apt to be set in many places next week. Is it a 'polar vortex'? No, because this isn't arctic air! Now, if this were occurring in January, that it probably would be! But it's July, so instead of it being hot and humid like it typically is at this time of the year, it will be much below normal with no heat and no humidity. For many, that will be a welcome sight, as it will decidedly save on energy costs! So don't buy into the hype! An upper-level low, yes! Polar vortex? Not really!
One storm is finally exiting the Northeast this afternoon, only to be replaced by another, slow-moving for the middle and latter stages of next week.
As the pattern becomes more amplified this weekend and early next week, look for it to warm up from the interior west toward the Plains, while it trends cooler east of the Mississippi.
A storm in Indiana will produce heavy rain in the mid-Atlantic into New England over the next 48 hours, but most of the rest of the nation will have little active weather into the weekend.
A powerful storm in Illinois is being blocked from a rapid advance to the East, resulting in heavy rains ahead of it, but also little cooling for the mid-Atlantic and Northeast behind it.
A strengthening storm in the eastern Plains will generate a lot of severe weather and heavy rain through Wednesday all the way to the Eastern Seaboard.
A storm developing over the southern plains late Sunday and Sunday night will help generate severe thunderstorms and flooding downpours from the Eastern Plains to the Eastern Seaboard through Wednesday.