INDIANAPOLIS — Hoosiers looking to celebrate the Fourth of July may have to wait as severe weather is expected to blow in.

Around 7:20 p.m., Fourth Fest attendees in downtown Indianapolis were told to seek shelter due to storms in the area.

The fireworks show has been delayed and is now expected to start at 10:30 p.m. The full show can be viewed on FOX59 NOW.

Numerous central Indiana counties were under a Severe Thunderstorm Watch or Warning earlier Saturday evening.

CarmelFest has announced that its fireworks will continue as scheduled at 9:45 p.m.

This is a developing story; check back for updates.

As many are celebrating America’s 250th birthday, a threat of severe weather looms, as watches and warnings have been issued for most Illinois and northwest Indiana counties for Saturday.

A Severe Thunderstorm Warning is in effect for Kane and Kendall counties in Illinois until 3:45 p.m.

A Severe Thunderstorm Watch has been issued for DuPage, Kane, Kankakee, Grundy, Kendall, and Will counties in Illinois and for Porter, Newton, Jasper, and Lake counties in Indiana until 7 p.m.

A Flash Flood Watch is in effect for Central Cook, De Kalb, DuPage, Eastern Will, Grundy, Kane, Kendall, La Salle, Northern Cook, Northern Will, Southern Cook, and Southern Will in Illinois and Lake in Indiana until 10 p.m.

A Flash Flood Warning is in effect for De Kalb, La Salle, and Lee counties in Illinois until 5 p.m.

Storm Prediction Center has areas along and south of I-80 at a Level 1 (out of 5) for severe chances. Strong-to-severe storms are expected around 2 p.m. and sunset. Frequent lightning, damaging winds and torrential downpours may accompany the strongest storms.

Be sure to stick with CBS News Chicago and the First Alert Weather team for the latest. 

TODAY

Mostly sunny and very warm to start, then the storm chance rises later in the day. Highs reach the upper 80s to near 90, with a light southwest breeze. A Heat Advisory remains in effect through 9 p.m. Saturday, and the better chance for showers and thunderstorms develops after mid afternoon, with any stronger storm capable of heavy downpours, hail, and damaging wind gusts.  

TONIGHT

Showers and thunderstorms remain likely early in the evening, then coverage gradually trends lower later at night. Lows fall into the low 70s, with light wind. It does not look like nonstop rain, but evening outdoor plans, including fireworks, will need a weather eye.  

TOMORROW

Partly sunny, warm, and still somewhat unsettled, with storms becoming more likely as the day goes on. Highs reach the mid 80s, with light wind. Much of the first half of the day looks more usable, but the second half becomes less reliable as showers and thunderstorms become more common.  

TOMORROW NIGHT

Showers and thunderstorms remain likely early, then fade back later in the evening and overnight. Lows settle near 70. It should turn quieter with time, and the air will feel a little less oppressive than the previous few nights.  

MONDAY

Partly sunny and still hot, but not quite as extreme as the holiday weekend. Highs reach the mid 80s, with a more humid feel and at least a low-end thunderstorm chance around. This looks more manageable than Saturday, but not completely quiet from start to finish.

MONDAY NIGHT

Partly cloudy and seasonably mild, with lows in the mid 60s. Any leftover storm chance looks limited, and quieter weather should win out for most of the night.

TUESDAY

Clouds and sun mix with a stray thunderstorm chance, and highs recover into the mid 80s. Heat is still around, but not as punishing as the late-week surge, and much of the day still looks usable.

TUESDAY NIGHT

Partly cloudy and muggy again, with lows in the upper 60s. Quiet weather generally holds overnight, even if a completely dry forecast is not guaranteed.

WEDNESDAY

 Mostly cloudy and humid with a thunderstorm possible in spots during the afternoon. Highs reach the mid 80s. This keeps the pattern a little unsettled, though it still does not look like an all-day rain setup.

7 DAY FORECAST

The main concerns are the late-day storm chance on the Fourth and then a hot, humid stretch that continues into next week. Saturday and Sunday both carry storm chances, with the Fourth looking more active later in the day and Sunday staying somewhat unsettled. After that, temperatures settle into the 80s with occasional storm chances lingering into midweek, so the pattern stays summerlike even though the worst of the heat eases back a bit.