Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
339 AM EDT Fri Sep 02 2022

Valid 12Z Fri Sep 02 2022 - 12Z Sun Sep 04 2022

...Dangerous and record-breaking heat continues to impact the West...

...Unsettled weather with isolated-to-scattered flash floods possible over
the next few days across much of the south-central United States before
extending eastward into the Ohio and Tennessee valleys by Saturday...

...Isolated strong to severe thunderstorms are possible this afternoon and
evening from parts of the central Plains to the Upper Midwest...

September is kicking off with scorching temperatures throughout the
western U.S., as highs are once again anticipated to threaten daily and
even monthly records headed into Labor Day Weekend. An anomalous
upper-level ridge anchored over the central Great Basin is the culprit for
these well above average temperatures. Highs into the upper 90s and triple
digits are expected this afternoon throughout a large portion of the West,
extending from the Southwest and Interior California northward to the
northern Great Basin and northern Rockies. Excessive Heat Warnings and
Heat Advisories currently include much of California, Nevada, Oregon,
Washington, and Idaho, where these dangerously hot temperatures are likely
to increase the threat of heat-related illnesses. For much of this region,
no relief is expected through the holiday weekend. In fact, temperatures
are forecast to increase to near 110 degrees on Sunday over interior
sections of California. Conversely, cooler weather will enter the Pacific
Northwest by Saturday, which will shift the late-summer heat eastward into
the northern High Plains this weekend. Highs around the century mark over
central and eastern Montana will equate to 20 to 30 degrees above average
when compared to climatology. This hot an dry weather pattern may also
create conditions ripe for wildfires to spread uncontrollably. Red Flag
Warnings have been issued from far northern California through the
northern Great Basin to further highlight the concern. Residents and
visitors throughout the western United States are urged to follow proper
heat safety and fire restrictions, check in on friends and family members
who may be more vulnerable to excessive heat, and heed warnings issued by
local forecast offices.

A stagnant and tropical airmass located throughout the southern tier is
forecast to lead to additional chances for heavy rain and flash flooding
today before an upper-level trough sliding eastward expands the threat
into the Ohio and Tennessee valleys on Saturday. More specifically, the
potential for intense rainfall rates and scattered flash floods has led to
a Slight Risk (level 2/4) of Excessive Rainfall through tonight over the
Texas Big Bend, the central Florida Panhandle, and an area extending from
southwest Missouri to eastern Texas. By this weekend, an approaching cold
front and upper-level trough will allow for moisture to stream northward
into much of the Ohio/Tennessee valleys and eventually the Appalachians
and northern Mid-Atlantic, while also focusing across southern Texas and
the western Gulf Coast. As a result, a Slight Risk of Excessive Rainfall
has been issued for Saturday over western Kentucky and Tennessee, as well
as a large area from the central Gulf Coast to the Edwards Plateau of
Texas. Heavy rain chances are forecast to linger over southern Texas on
Sunday. Meanwhile, a surge of monsoonal moisture (aided in part by
Tropical Storm Javier over the eastern Pacific) may lead to isolated
downpours capable of producing flash floods over parts of southern Arizona
today and a much broader section of the Southwest on Saturday.

Elsewhere, an advancing cold front could lead to isolated severe
thunderstorms from the central Plains to the Upper Midwest. Large hail and
damaging wind gusts are expected to be the main threat. Warm and above
average temperatures will be found ahead of this cold front and fuel the
aforementioned thunderstorms. Highs into the 90s are forecast from the
central High Plains to the Midwest. Rather warm temperatures for this time
of year are also forecast across the Great Lakes, Northeast, and
Mid-Atlantic through this weekend, with highs in the upper 80s and low 90s.

Snell


Graphics are available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php