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Dangerous heat continues today, with peak heat index values of 105 to 118 degrees.

Scattered showers and thunderstorms possible overnight tonight into early Tuesday (20-30% chance).

Temperatures settle back into the upper 80s and lower 90s Tuesday and Wednesday, with precipitation chances returning Thursday and Friday.

Discussion

A broad upper-level ridge across the Rockies into the Great Plains is leading to hot weather across the western half of the CONUS. This combined with humidity from southerly flow advecting moisture in from the Gulf with added agricultural contributions is leading to the high heat/high humidity scenario from the last couple of days. Good news is that the weak frontal boundary dropping south across eastern Nebraska and western Iowa today will help to push off some of the added moisture from the Gulf as well as advect in milder temperatures starting tomorrow. Yes, today will be our last day of extreme heat, at least for this stretch, with highs tomorrow back in the upper 80s to low 90s and heat indices back down below 100.

This afternoon we have a few chance of rain-up showers and storms that have developed along the front moving through mostly east of our Iowa counties. These are occasionally clipping far eastern Shelby and Pottawattamie Counties, though. Not expecting anything severe, but worst case we could see 1-1.25 inch hail. The better chance for storms to impact our area will be overnight into early Tuesday. Storms from central Nebraska should be weakening and falling apart as they move into eastern Nebraska leading to greater chances (20- 30%) over our far western counties, generally decreasing as you get farther east. While these storms should be fairly weak, we could see strong winds if any hold together into our area. Another scenario to watch is the the high-res rapid-refresh model redevelops some scattered showers and storms along the remnant boundary around 16-18Z Tuesday along and east of the Missouri River. These again likely won't be severe but could produce some gusty winds.

Cloud cover will linger through Tuesday morning from the overnight storms as well as any late-morning showers/storms. We should see gradual clearing Tuesday afternoon into the evening allowing temperatures to warm into the upper 80s to low 90s. Tuesday night into early Wednesday we may see another chance (20%) for showers and storms clipping our southeast Nebraska counties, but latest trends keep this activity south and west of our area. Pattern stays fairly stagnant into Wednesday, though a modest bump in humidity may be observed as we see weak southerly flow move back in as the High over the region starts to slide east.

Toward the end of the work week we see a more substantial cool-down ahead as a trough moving out of the PacNW pushes east overtopping the ridge. As this approaches, we'll see a low pressure system develop and track along the Nebraska-South Dakota state line creating shower and storm chances late Wednesday night into Thursday. This Low lingers until it gets picked up by the upper- level wave Thursday afternoon, leading to a fairly rainy day on Thursday into Thursday night. The National Blend of Models keeps highs in the upper 80s to low 90s on Thursday, likely due to uncertainty in coverage of storms from differences in the track timing/placement of the surface Low. Greater coverage of showers and storms likely would lead to cooler highs than currently predicted. In any case, cooler air out of central Canada will likely move in behind this system for Friday going into the weekend for a better reprieve from the heat.

While we see milder temperatures Friday into Saturday, we see the ridge start to build back up to our west, looming. Temperatures trend back upward Sunday into Monday next week.