A strong cold front pressing south and east through the Nation's Heartland will collide with an exceptionally hot and muggy air-mass to produce widespread thunderstorms into Thursday night.
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he region most at-risk for flash flooding (Moderate Risk) and severe storms (Enhanced Risk) is the central High Plains and portions of Tennessee.
Robust thunderstorm activity could produce any combination of flash flooding, damaging winds, large hail, and tornadoes there.
The severe weather and flash flood threat (Slight Risk) is also present for many locations farther east, which would extend into the evening hours on Thursday.
By Friday the cold front continues to advance farther south and east, placing the best threat for flash flooding and strong-to-severe storms over the southern High Plains, Mid-South and Northeast.
By Saturday morning, much of the Mid-South and Northeast will trend drier as the cold front exits off the East Coast.
However, the front becomes stationary over the Gulf Coast states, setting up a stormy Saturday in the South.
For the remainder of the work-week, much of the southern tier (south of the advancing front) and western third of the U.S. will remain mired in this prolonged and dangerous heat wave.
Record breaking daytime highs and warm morning lows will be common from the Desert Southwest and South Texas all the way east to Florida.
The forecast calls for daytime highs to soar into the triple digits in the Desert Southwest and Southern Plains, while the Gulf Coast and Mid-South can expect daytime highs in the upper 90s that coincide with oppressively high dew points through Friday, resulting in sweltering heat indices as high as 120 degrees in some spots.
Meanwhile, daily low temperatures remain quite warm with breaking record warm daily minimums expected, which will limit relief from the heat overnight.
Florida will also contend with stifling heat ahead of the front, where lighter than average winds have led to above average sea surface temperatures due to a weaker than average Bermuda High.
Please visit heat.gov, as well as the Key Messages issued by the Weather Prediction Center and Climate Prediction Center for more information on impacts from the heat wave.
Behind the cold front, cooler and drier air sweeps in.
By Friday, parts of the Central Plains could see daytime highs that are as low as 15-20 degrees below normal.
The East will see milder air arrive by Saturday, including in the Mid-Atlantic and Northeast where daytime highs look to be several degrees below normal and humidity levels that are more refreshing for mid-late July. ■