THE HEAT DOME IS BUILDING IN

As we head into July, a classic summer heat dome is looking likely to take over the forecast for the forseeable future bringing dangerous temperatures andd triple-digit heat indices. Sunday, morning storms and cloud debris may keep temperatures in check slightly, but by Monday low/mid 90s will be commonplace daily dewpoint values well into the 70s. A sticky combination.

I did want to touch on the potential for some strong storms in northern Iowa and Illinois Sunday late morning/early afternoon. A remnant complex of thunderstorms will likely approach the area from overnight activity well to the west While at this time the threat of severe weather appears to be limited (in fact SPC has no risk area), I do think there is some potential this line could re-intensify over the area as we start reaching peak heating, riding over the hot temperatures. Areas most likely to see storms appears to be north of I-80, with the window after 10 a.m. and exiting our area around 2 p.m.

Several of the other convective models are also showing a line of storms coming across Iowa Sunday late morning/early afternoon including the NSSL WRF, ARW and the NAM. It certainly has me interested.

I would not let your guard down early Sunday for some rowdy storms if conditions come together the right way.

Some analogs I use to forecast are hinting at some severe weather potential across northern Iowa and Illinois Sunday, and this activity in the earlier part of the day would be the likely culprit. Certainly something to watch as the morning evolves. If you have outdoor plans Sunday make sure to check the forecast in the morning and look for any active watches/warnings.

What follows is a strengthening ridge over the eastern CONUS letting the heat and humidity pump into the Upper Midwest through next weekend. One potential "bust" scenario for daily excessive heat is the fact the storm track, especially Monday-Wednesday, is sitting pretty close to the area. Storms and cloud cover from overnight/morning activity could aid in keeping temperatures in check. The storm track shifts closer to home by Thursday with our storm chances increasing.

That could also lead to severe weather episodes, so pick your preference with that.

The European Ensemble for example through Friday has the heaviest rain to the northwest of the area with that active storm track earlier in the week, but again I think Thursday/Friday we will have an increasing storm and potential severe threat as the upper air support shifts a bit east directly overhead. This certainly could have some complications for the Fourth of July festivities.

The EPS

The GFS

Model Blend

An early look at rain chances on July 4 - generally all modeling is showing something in the vicinity. Once we get in range of the higher resolution modeling we will have an increase in confidence with time, but at least for now the hot, humid and stormy pattern may give us some of nature's fireworks overhead. Deterministic GFS, Euro Ensemble and the Model Blend all have some measurable rainfall in the area. Coupled with the forecast heat and humidity, this would likely be in the form of thunderstorms.

Enjoy the heat! I am working on some videos following my chasing trip and hope to get those uploaded in the coming week or so. Hope to share those with you soon!

Stay cool, friends.

-Meteorologist Nick Stewart