For 2 weeks I've been pointing out the potential for a heat wave to develop here in the Midwest. The idea is now well supported on models and NOAA has even issued a hazardous weather outlook for excessive heat. At some point next week heat index values have the potential to reach 105-109 degrees in much of the central Midwest.
A hazardous weather outlook for excessive heat is issued when heat indices are expected to be in the top 10 percent of heat indices for a given location. They also use the criteria of wherever a heat advisory or excessive heat warning may be issued.
The EURO is the model that has been leading the way with the heat and that's what I'm relying on as my principle guidance. I'm a few degrees cooler and think its 100 degree readings might be a tad high. We'll see if that trend holds in coming days. The GFS recently went through an upgrade that has turned that model into junk. It's hardly worth looking at as it holds highs mainly in the 80s. Here are the 10 day meteograms showing highs and lows off the EURO for some select Midwest Cities.
The Quad Cities.
While some form of heat will dominate through much of the next 10 days, the period July 17th-21st (as you can see in the meteograms) appears to be the worst. By then dew points are projected to be in the range of 70-75.
With highs around 97, that would push heat index values into the range of 105-110 degrees.
If by some chance the EURO is correct and the actual temperature hits 100 in Cedar Rapids, that would be the first time we've hit the century mark here since August 30th of 2013...2142 days ago as of Friday!
Additionally, if we go 9 consecutive days with highs in the 90s that would be the first time that's happened since 1995, 24 years ago!
For the most part, thunderstorms look confined to far northern Iowa, Minnesota, and Wisconsin the next 8-10 days with the storm track confined to that part of the Midwest. A few could be found in those areas Saturday but they should be widely scattered as warm air aloft builds a hefty cap by Sunday. The EURO has this for 10 day precipitation.
That equates to departures that look like this.
I think it's safe to say as far as sensible weather goes there's not much to be concerned about aside from the growing heat. It's July and you expect the steam, it's the duration of it that will be a bit unusual. All hail summer. Roll weather...TS