After a brutally hot and record-setting weekend, blistering temperatures are expected to continue into the upcoming workweek for millions.
About 141 million people were forecast to experience highs above 90 degrees on Monday, with 51 million of those bracing to soar over the century mark.
Heat alerts were up Monday for parts of 16 states from central California to the Mississippi River Valley. For some locations, the hot temperatures combined with high humidity will make it feel up to 110 degrees. For other locations, the raw air temperature will get as high as 110 degrees.
While the core of the heat was expected to be over the central part of the lower 48 to start the week, the heat is expected to spread east with time, bringing the first official heat wave of the year to the nation's capital.
Dallas, over the weekend, hit 105 for the fourth time this summer. This is the third most to date, where only 1980 and 1954 had more. They will add at least three more to that total, with highs Monday through Wednesday forecast to be 110, 109 and 109 respectively.
Elsewhere across Texas, Austin, San Antonio and Houston are all already having their hottest summer on record. All three cities could set record highs over the next few days.
When the heat expands into the Mid-Atlantic and Northeast, several locations will see several consecutive days in the 90s. While New York City has already experienced one official heat wave (defined as three straight days above 90 degrees), the nation's capital has managed to evade that echelon of heat.
But Washington's luck has run out, with each day this week forecast to be in the 90s, snapping their heatwave-free streak.
As has been the case the past several weeks, the summer heat and humidity will help to fuel severe thunderstorms across several regions.
On Monday, strong and severe thunderstorms were forecast for 19 million people across two areas, the northern Plains and the Northeast. Across both regions, damaging winds will be the main risk followed by hail and isolated tornadoes.
The Northeast will actually experience two rounds of storms. Morning rounds of storms, while not severe, provided an early wake up call with house-rattling thunder and torrential downpours.
The second round of storms Monday afternoon and evening, however, is expected to be stronger. The second round of storms will also have a higher flood threat due to already soaked soils.
About 12 million people are under Flood Watches across the Ohio Valley (including Cincinnati) until noon, and the Mid-Atlantic (including Washington, D.C. and Baltimore) until Monday evening. Rainfall rates of 1 to 2 inches per hour could provide quick bursts of heavy rain, reduce visibility, and prompt flash flooding.
On Tuesday, more storms will be possible across the northern Plains and Upper Midwest into the northern Great Lakes, including the cities of Green Bay and Duluth.