The record heat wave that has gripped areas from southeast New Mexico into central to south Texas over the past week will begin to expand northward into the Central Plains and eastward into the Middle to Lower Mississippi Valley and Lower Tennessee Valley.
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High temperatures are expected to be 10 to 20 degrees above average over the next days from the Southern to Central Plains into the Middle to Lower Mississippi Valley, resulting in high temperatures in the upper 90s to lower 100s.
Along with the heat, high humidities levels will continue to produce potentially life threatening heat indices across all of these areas through the remainder of this week.
Heat indices values will be in the 100 to 120 degree range across all of these areas, with the max axis of heat indices in the 110-120 degree range stretching across the eastern third of Texas, along the Central Gulf coast and north through the Lower Mississippi Valley and Lower Tennessee Valley.
This will include the major metro area of Dallas- Fort, San Antonio, New Orleans, Little Rock, Jackson, Memphis, Montgomery and Nashville.
Heat advisories and excessive heat warnings are currently in effect across all of the above described areas and will likely remain so through the end of the week.
Along with the potential for record high temperatures across these areas over the next few days, there will also be the likelihood of record high minimum temperatures.
This will not allow for any significant period of cooling from the record day time highs, increasing the heat related dangers.
On the northern edge of the heat wave across the Southern Plains, a stationary frontal boundary stretching from western Nebraska into western Kansas, eastward across Oklahoma into southern Arkansas will be the focus for severe thunderstorms from Tuesday afternoon into Tuesday night for areas of the Central to Southern Plains into the Lower Mississippi Valley.
Across these areas, the greatest risk of severe weather will be from large hail and strong winds, with a lesser risk from tornadoes.
While it has been relatively cool over the past few weeks across much of California, building mid to upper level heights will be leading to an increasingly hot weather pattern for the interior Valleys of California starting on Thursday and continuing into the weekend.
Excessive heat watches are currently in effect for much of the Sacramento and San Joaquin Valleys.
While temperatures are not expected to be above average across the Southwest, continued dry conditions with low relative humidities combined with gusty winds in excess of 20 to 30 mph will support a widespread region of elevated to critical fire weather conditions from the Four Corners region, across much of Arizona, New Mexico and Southwest Texas.
The ongoing fires across portions of Canada will continue to bring poor air quality over the next few days across the north central tier of the nation from the Upper Mississippi Valley, through the Great Lakes and into the Mid West.
An area of low pressure forecast to push eastward across south central Canada over the next few days will tap the ongoing wildfire smoke of south central Canada, sending it southward in the counter clockwise flow around this area of low pressure. ■
Under an intense surge of arctic air, Friday morning will begin with the coldest temperatures so far this season across much of the central and eastern U.S. with blustery conditions and a piercing wind chill.