Storms Will Rumble Across Central and Eastern U.S. as Heat Builds

A building heat dome will support the development of several rounds of thunderstorms across the central and eastern U.S. heading into the weekend. The hot and stormy pattern will have some staying power, persisting into next week. Here is a look at what to expect.

Increasing Temperatures Will Support the Development of Storms

Warm and moisture-rich air will drive the weather for the eastern half of the nation over the next few days. The unsettled trend will raise the risk of potentially dangerous flash flooding and derechos.

Forecasters are predicting that a large area of high pressure will form and strengthen in the days ahead. While the high pressure will put a lid on rain and storms for some areas, the clash of the dry and humid air will also increase the chances for stormy conditions in other areas.

The heat dome will take root over the southern tier of the Rockies, the southern Plains, and the lower Mississippi Valley well into next week. This development will send the temperatures climbing within the heat dome. Rain activity is expected to decrease within the core of the dome; however, the edges of the area of high pressure will be at an increased risk of storms.

The mercury will inch up as the ground begins to dry out. You can expect widespread highs to hover in the mid 90s to the low 100s in the southern third of the country by next week. Real feel readings will soar even higher in the south-central U.S., ranging between 105 and 115 degrees during the peak afternoon heating hours.

Thunderstorm activity will be the most prevalent on the edges of the building heat dome. The bulk of the action is expected along the northern and eastern flanks of this area of high pressure.

Forecasters are warning that long-tracking complexes of storms packing heavy rain and gusty winds will track across the northern and central Plains before reaching the Ohio Valley and the southern Appalachians. Some of these storm cells could sneak into the coastlines of the southern Atlantic and the northeastern Gulf Coast by next week.

The increase in rain showers and storms will amplify the threat of flash flooding. It is also possible that derechos could come to life out of these storm cells.

Timing of Storms

The first batch of storms is forecast to develop over the northern Plains and the Upper Midwest on Friday evening. This is when forecasters are predicting that the threat of a derecho could intensify. The Storm Prediction Center (SPC) defines a derecho as a thunderstorm complex that covers at least 400 miles. A storm must also have a width of at least 60 miles and pack wind gusts of 58 mph or higher for much of the path to be classified as a derecho.

Places such as Waterloo, Iowa, will see the highest threat of storms in the overnight hours Friday and into Saturday. Temperatures will remain at moderate levels due to the cloud cover. Highs will top out in the upper 70s on Friday before falling into the upper 60s overnight. Saturday will dawn with lingering storm activity that will keep the temperatures in the low 80s for a high. After a mostly dry Sunday, more storms are waiting in the wings after the sun goes down.

Minneapolis will be on the northern fringe of the storms on Friday night. The Twin Cities are forecast to see storms ignite in the evening and overnight hours. Temperatures that max out in the mid 70s on Friday will slip into the upper 60s after the sun goes down. It will be a breezy day with winds out of the south at 10 to 20 mph.

Heading into Saturday, the line of storms is forecast to move farther to the southeast. This will put the Midwest in the bullseye of the activity. Even in the absence of an official derecho, these storms could pose a number of hazards over the central U.S. and to the east.

For instance, Peoria, Illinois, will start the day under the threat of locally strong thunderstorms. While the moisture will clear out in the afternoon, another wave of storms is on deck overnight. It will be a warm day in this part of the Midwest with highs of about 88 degrees and lows that slip into the mid 70s. Peoria will see a renewed threat of storms on Sunday afternoon and evening to bring the weekend to a close.

It could also be a rocky start to the weekend in Chicago. The Windy City is expecting scattered storms on Saturday morning with partly cloudy skies on the horizon for the latter part of the day. The forecast is also calling highs of about 84 degrees, lows that land at the 70-degree mark, and winds out of the southwest at 10 to 15 mph.

The unsettled weather will take longer to arrive in the southeastern flank of the impact zone. Louisville, Kentucky, is forecast to see dry but cloudy conditions early with the odds of storms increasing in the afternoon and evening hours. It will be a muggy day with high humidity levels and highs in the upper 80s. Scattered storms will linger through the day Sunday and Monday.

Although some of the communities in the path of the widespread storms could use the moisture, the combination of the heavy rain and the high winds could present another set of risks. This is a good time to ensure that all of your smartphone weather notifications are enabled.

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