Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
329 PM EDT Sat May 20 2023

Valid 00Z Sun May 21 2023 - 00Z Tue May 23 2023

...Above-normal temperatures likely to continue across much of the western
U.S. through early next week...

...Severe storms possible across portions of the Northwest and the
northern Rockies on Sunday...

Following a day of well above-normal to record-breaking heat, a
well-defined cold front is forecast to move through the northwestern U.S.,
reaching the northern Rockies on Sunday -- bringing cooler temperatures
and an increased chance for strong to severe storms.  Severe thunderstorms
are possible from eastern Washington and Oregon into northwestern Montana
Sunday afternoon and evening.  Storms that develop may produce large hail
and damaging wind gusts.

Elsewhere across the western U.S. and into the northern Plains,
temperatures are forecast to remain above-average through the remainder of
the weekend, into Monday.  Ahead of the cold front, well-above normal
temperatures will shift from the northern Rockies into the Plains, with
daytime temperatures expected to reach 10-20 degrees above normal across
eastern Montana and the western Dakotas on Monday.

From the Southwest into the Great Basin and southern Rockies, showers and
thunderstorms developing this afternoon may continue into this evening,
with an isolated threat for heavy rainfall and flash flooding.  Storms are
likely to diminish overnight before redeveloping once again on Sunday.

Below-normal temperatures are forecast to continue from the southern
Plains to the Southeast through the early part of next week as a cold
front drops south through the region.  The front will remain a focus for
showers and thunderstorms as it settles along the Gulf Coast.

Farther to the north, the front will push east through the remainder of
the eastern U.S., driving a swath of showers and thunderstorms through the
Northeast and the Mid-Atlantic states this evening.  An area of low
pressure lifting north ahead of the front is expected to increase the
threat for heavy rain along the Northeast coast into this evening.

Behind the front, high pressure and dry conditions are forecast to spread
east from Midwest into the Mid-Atlantic on Sunday.

Pereira

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