A stationary front will be the focus for severe thunderstorms and areas of heavy rain, tracking eastward from the central Plains into the Ohio Valley in the short term forecast.
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These thunderstorms are the result of upper-level energy ejecting off the Rockies and into the central U.S., helping to force precipitation.
The strongest storms containing the heaviest precipitation are expected to gradually shift eastward each day, stretching from the central & southern High Plains on Friday toward the Appalachians and Mid-Atlantic on Sunday.
Slight Risks for Excessive Rainfall are in effect Friday and Saturday over the central High Plains and Midwest.
Thunderstorm complexes developing along the front will likely contain heavy downpours, hail, and damaging wind gusts, per the Storm Prediction Center.
As a result, Slight Risks for severe weather are in effect through the weekend across the region, with an Enhanced Risk of severe weather on Saturday over the lower Ohio River Valley.
By Sunday morning, a more well-defined low pressure wave will enter the lower Great Lakes region and Northeast, resulting in more synoptically forced precipitation.
Given the locally heavy rainfall that has occurred over the previous week, a Marginal Risk for Excessive Rainfall is in effect over much of the Ohio Valley into the Northeast on Sunday.
The same shortwave energy responsible for producing thunderstorms over the central US will begin to erode the upper ridge responsible for the ongoing long-term heat wave across the southern Plains and lower Mississippi Valley.
As the upper ridge weakens, the highest temperatures and heat indices will slowly trend down, though sweltering heat is anticipated to continue across the Southeast, particularly along the Gulf Coast.
Several cities across the lower Mississippi Valley and Southeast are expected to break their daily warmest nighttime low records through the weekend.
Heat-related danger remains elevated due to the longevity of this heat wave.
As the ridge moves across the south-central Plains, heat will build along the West Coast and reach portions of the Northern Plains by Sunday.
Afternoon temperatures in the interior valleys of California may climb over 100F to near 110F at the hottest locations on Saturday.
The Desert Southwest will see temperatures climb well into the 110s.
The risk of heat-related illnesses will be increased through the weekend.
In addition to the heat and the severe storms, Canadian wildfire smoke is expected to continue impacting portions of Great Lakes and East Coast over the next few days.
However, air quality is expected to slowly improve due to a combination of thunderstorm activity and dispersion of the smoke as we head into the weekend. ■