PATTERN LOADING UP IN A BIG WAY

If you want big-time rains in the Midwest, this seven-day stretch of weather is how to do it. Where exactly the heaviest rainfall axis sets up is still a bit wavering, but it will certainly be very close to the region, and given the likely northern-favoring axis of heavy rain, a river flooding concern is something at least worth monitoring going forward. Forecasts are indicating 5"+ of rainfall a pretty good likelihood for some.

Let's start with the upper-level pattern. Persistent west/southwest flow on the northern fringe of the ridge is forecast to set up for multiple days, likely starting Monday through at least Friday. This is the ring of fire, with storms riding on the northern periphery of the intense heat and humidity across the central US. That heat will likely be record breaking for some.

SUNDAY

Sunday will likely be the hottest day locally with temperatures surging into the mid-90s to near 100 for much of the region. Temperatures are forecast to be near or at record levels for many locations including Chicago, Omaha and Sioux City.

The record for the Quad Cities Sunday is 98° set more than 100 years ago in 1911. We will remain just a few degrees from that, but I do not want to dismiss how dangerous this heat can be. Heat stroke can settle in quickly, so please stay hydrated and take frequent breaks if you have to be outside. This applies for much of the upcoming week.

MONDAY

Monday is when we can really see how the pattern will likely shape up. That sharp gradient in temperatures from southwest Kansas to northern Wisconsin is the line where storms and heavy rain is likely. Notice eastern Iowa remains hot with more comfortable temperatures in northwest Kansas. Forecast highs in Chicago will likely break records again.

The European Ensemble 24-hour precipitation mean shows this heavy rainfall axis especially across northern Kansas into Central Iowa. The mean is over 1" which is quite a strong signal for the heaviest rainfall. Any thunderstorms that form would also have some severe weather potential, especially damaging wind gusts with a secondary threat of large hail.

The Storm Prediction Center already has a Level 2 of 5 Risk, a Slight Risk, in place across Iowa and into central Wisconsin. At the time of posting this was the Day 2 outlook, so there's likely many changes that can evolve with this outlook. The Quad Cities for the time being is in the Level 1 of 5 risk, a Marginal Risk.

High-resolution model guidance is starting to get in range for Monday. The HRRR shows widespread thunderstorms along the boundary by Monday evening. There will be pockets of damaging wind gusts and large hail with the strongest storms, in addition to torrential rainfall.

HREF instability mean of the high-resolution models has CAPE, or instability, reaching 3,000j/kg. This well more than supportive for severe thunderstorms.

TUESDAY

The pattern remains loaded on Tuesday with a similar boundary orientation with the storm track likely southern Nebraska, through central Iowa and into southern Wisconsin. Temperatures remain hot with highs pushing into the 90s for far eastern Iowa and northern Illinois.

Tuesday, once again you can see how the European Ensemble is pinging the heaviest rainfall threat right along that temperature boundary from Nebraska through southern Wisconsin. Once again there will likely be some severe weather potential along this line of thunderstorm activity, once again a primary wind and hail threat.

Moisture levels of the atmosphere, measured by Precipitable Water, are forecast to be very close to record territory with PWATS near 2.0" - in the 99.5th percentile. Thunderstorms in this environment will be very efficient rainfall producer with flash flooding a concern during this period.

The Euro Ensemble keeps the pattern quite active through next weekend, so this is likely going to be a rather prolonged period to watch for heavy rainfall, strong storms and river flooding. For what it's worth, any Fourth of July activities on area rivers could be impacted by high water. Those with interests boating or camping along rivers should keep an eye on river forecasts as the heavy rain develops.

Let's wrap up with a look at model guidance for the next week in terms of rainfall.

EUROPEAN ENSEMBLE

GEFS - AMERICAN ENSEMBLE

NATIONAL BLEND

Generally you can see the heaviest rainfall will likely be just west/northwest of the Q.C. region, but there are certainly elevated rain chances locally almost daily. I would say comfortably, 3-5" for a large swath of the Midwest is likely, it just continues to be a game of where exactly the boundary sets up day to day.

Have a great rest of the weekend everyone!

-Meteorologist Nick Stewart