
A heat wave over the Southwest will intensify late week, peaking and expanding into the Intermountain West and northern High Plains this weekend. Severe thunderstorms and heavy rain are expected over portions of the Plains and Mississippi Valley tonight, which will shift to parts of the Upper Midwest and mid-Mississippi Valley Friday. Monsoonal showers and flooding persist in the Desert Southwest. Read More >
Coverage is affected by many factors.
Read the Coverage Map Notes below to understand these factors on the state and individual maps.
The coverage statistics and maps are calculated using a computer model and station data, assuming ideal conditions. Actual coverage may be 5 to 10 percent below the computer-predicted coverage due to the following factors: