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

Valid 00Z Sat Sep 03 2022 - 00Z Mon Sep 05 2022

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

...Flash flooding concerns from Southern Plains to Ohio/Tennessee Valleys
this weekend...

...Isolated severe thunderstorms are possible this evening over parts of
central/southern Arizona and the Lower Colorado River Valley...


September is off to a searing start in the West with record breaking
temperatures and fire weather expected to expand and settle over that part
of the country this Labor Day weekend. A stubborn area of high pressure
will be the driving force behind the dangerous heat, sending highs into
the 90s and 100s in many parts of the West. Portions of Montana will
experience high temperatures between 20-30 degrees above average on
Saturday as the upper-ridge amplifies over the state. The abnormally warm
airmass will likely tie or break widespread high/low temperature records
from the Northern Rockies to the Great Basin and down into southern
California this weekend. Excessive heat watches, warnings and heat
advisories are in effect for much of the West as a result.

A slow moving upper trough and associated surface cold front will be the
focus for showers and thunderstorm activity across the Midwest this
weekend. Shortwave energy scooting across southern Texas will contribute
to a flash flooding threat through Sunday. A moist airmass with and ample
surface heating will drive a severe thunderstorm threat over parts of
central-southern Arizona, southeastern California and southern Nevada this
evening where a slight risk was issued by the Storm Predicion Center.
Localized heavy rainfall and flash floods may impact portions of the big
bend region of Texas and the Ozarks tonight where slight risks are in
effect. The greatest flash flooding threat shifts east with the cold front
into the Ohio/Tennesee Valley on Saturday and Sunday. The expansion of the
upper trough into the southern Plains late on Saturday will allow for
increased moisture advection into the region through Sunday. A slight risk
of excessive rainfall leading to flash flooding continues for the south
Texas coast on Sunday as a result. A swath of moderate to heavy rainfall
is likely to occur across the Appalachians on Labor Day.

Kebede


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