The persistent mid to upper level high parked over the Southwest will move little over the next few days.
Article continues below
This will continue the string of days in which record high temperatures are set across portions of the Southwest into the Southern Plains and across South Florida.
There has been a reduction over the past few days in the number of records set from the Southwest into the Southern Plains and South Florida compared to the peak set last week.
However, with the upper ridge remaining in place, much above average temperatures and dangerous heat indices will continue across the Southwest, through portions of the Plains and over South Florida.
Across these areas excessive heat warnings and heat advisories are currently in effect.
Over the next several days, nearly all of the Lower 48 will have above average temperatures as the Southwest to Southern Plains upper ridge builds to the east and northeast.
The one exception to this will be across the Northern Rockies into the Pacific Northwest where a cold front moving off the northeast Pacific will produce below average temperatures.
Along the northern peripheries of the building upper ridge from the Southwest into the mid section of the country a frontal zone will drape from the Northern Plains into the Mid West and Mid Atlantic region.
This frontal boundary will be the focus for areas of active thunderstorms, producing areas of severe weather, heavy rains and isolated flash flooding across the Northern Plains and Mid-Atlantic on Tuesday and across the Mid-West on Wednesday.
Northwesterly to westerly mid to upper level flow across central to southern Canada into the northern tier of the U.S. will continue to transport the persistent western Canadian wild fire smoke southeast.
This will produce poor air quality from the Northern Plains, southeastward into the Great Lakes and Ohio Valley region over the next few days.
While temperatures are expected to be below average across the Northwestern U.S. over the next few days in the wake of the inland moving cold front, dry conditions, lower relative humidities and gusty winds will support an elevated to critical fire weather threat across the Northern Great Basin and Northern Rockies. ■
A strong storm that originated over the Pacific has tracked through the Great Basin and is currently transitioning across the Rockies to redevelop across the central High Plains later today into early Saturday morning.