Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
313 PM EDT Mon Sep 06 2021

Valid 00Z Tue Sep 07 2021 - 00Z Thu Sep 09 2021

...A Heat Wave will encompass much of the West with Record High
Temperatures possible...

...A Strong Cold front will bring the threat of locally Heavy Rains and
Severe Weather from the Upper Mississippi Valley through the Great Lakes
region Monday night into Tuesday...

A mid to upper level ridge is expected to continue to strengthen across
the Great Basin early this week.  This upper ridge will move only slowly
eastward over the next several days, setting the stage for widespread much
above average temperatures across much of the western U.S. this week.  
Heat advisories and Excessive Heat Warnings are currently in effect across
large sections of California into southern Nevada and northwest Arizona
where high temperatures are forecast to remain above 100 degrees F through
much of this week.  Record high temperatures are possible over the next
two days across portions of the Great Basin into the valleys of
California.  In addition to the heat, there will also be a fire weather
threat across large portions of the west where no precipitation is
expected over the next several days, exacerbating the the ongoing extreme
to exceptional drought conditions.

While the mid to upper level ridge builds across portions of the west, a
mid to upper level trough will be amplifying downstream across the Great
Lakes into the Ohio Valley region.  This will propel a strong cold front
from the Upper Mississippi Valley Monday night and across the Great Lakes
on Tuesday.  An organized region of thunderstorms are possible along this
front, bringing the threat of locally heavy rains, isolated flash flooding
and the risk of severe weather from the Upper Mississippi Valley through
the Great Lakes from Monday night into Tuesday.  In the wake of this
front, cooler than average high temperatures are expected Tuesday across
portions of the Northern Plains, Upper Mississippi Valley and Upper Great
Lakes region and across all of the Great Lakes, Ohio Valley into the Upper
Mississippi Valley on Wednesday.

Elsewhere, showery conditions possible along the Gulf coast, Southeast and
Florida, along and to the south of a weakening frontal boundary across the
Southeast. 

Oravec