Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
334 PM EDT Fri Jun 20 2025

Valid 00Z Sat Jun 21 2025 - 00Z Mon Jun 23 2025

...There is a Slight Risk of excessive rainfall over parts of the
Upper Mississippi Valley/Upper Great Lakes on Friday...

...There is an Enhanced Risk of severe thunderstorms over parts of
the Northern Plains/Upper Mississippi Valley/Upper Great Lakes on
Friday...

...There is a Slight Risk of severe thunderstorms over parts of
the Upper/Lower Great Lakes on Saturday...

...There is a Critical Risk of fire weather over parts of the
Great Basin/Southwest...

A front extending from the Great Lakes to the Northern High Plains
and then southwestward to the Great Basin/Central California will
have a wave of low pressure over the Northern High Plains that
moves to the Upper Mississippi Valley by Sunday evening. Moisture
from the western Gulf of America will stream northward over the
Mississippi Valley and overrun the boundary, triggering showers
and thunderstorms with heavy rain over the Upper Mississippi
Valley and into the Upper Great Lakes. Therefore, the WPC has
issued a Slight Risk (level 2/4) of excessive rainfall over parts
of the Upper Mississippi Valley/Upper Great Lakes through Saturday
morning. The associated heavy rain will create mainly localized
areas of flash flooding, with urban areas, roads, small streams,
and low-lying areas the most vulnerable.

Furthermore, upper-level dynamics and upper-level energy will
create showers and severe thunderstorms over parts of the Northern
Plains into the Upper Great Lakes. Therefore, the SPC has issued
an Enhanced Risk (level 3/5) of severe thunderstorms over the
Northern Plains/Upper Mississippi Valley/Upper Great Lakes through
Saturday morning.  The hazards associated with these thunderstorms
are frequent lightning, severe thunderstorm wind gusts, hail, and
a few tornadoes. However, there will be an added threat of EF2 to
EF5 tornados over North Dakota and northwestern Minnesota. In
addition, there will be an increased threat of severe thunderstorm
wind gusts of 65 knots or greater and hail two inches or greater
from the Northern Plains to the Upper Great Lakes.

Moreover, low pressure over Eastern Canada will move farther
northeastward over Canada, producing scattered rain with embedded
thunderstorms over parts of Northern New England through late
Friday night. Additionally, moisture and upper-level energy will
produce scattered showers and thunderstorms over parts of the Gulf
Coast States and the Southeast/southern Mid-Atlantic Coast through
Saturday morning.

On Saturday, the axis of severe thunderstorms moves eastward to
the Upper Great Lakes and Lower Great Lakes. Therefore, the SPC
has issued a Slight Risk (level 2/5) of severe thunderstorms over
parts of the Upper Great Lakes and Lower Great Lakes from Saturday
through Sunday morning.  The hazards associated with these
thunderstorms are frequent lightning, severe thunderstorm wind
gusts, hail, and a few tornadoes.

Likewise, on Saturday, moisture and upper-level energy will
produce scattered showers and thunderstorms over parts of the Gulf
Coast States and the Southeast/southern Mid-Atlantic Coast through
Sunday evening. Showers and thunderstorms will also develop over
parts of the Northeast.

Meanwhile, an upper-level low will move across the Pacific
Northwest into the Northern High Plains by Sunday. The energy will
produce rain and snow at the highest elevations over the Cascades
overnight Friday into Saturday afternoon. Rain will continue over
the Northwest through Sunday afternoon. Further, wet mountain snow
will develop over parts of the Northern Rockies late Friday night,
prompting a Winter Storm Warning over parts of Glacier National
Park from early Saturday morning to Sunday afternoon. At lower
elevations, showers and thunderstorms will develop over the region
through Sunday evening. Also, showers and thunderstorms will move
into parts of the Northern Plains and Upper Mississippi Valley on
Sunday.

Elsewhere, deep boundary-layer mixing is expected across the Great
Basin during the afternoon, with surface temperatures climbing
into the 90s to 100 F and relative humidity falling into the
single digits. The deep boundary-layer mixing into the strong flow
aloft, coupled with a tightening regional pressure gradient, will
contribute to an expansive area of 20-25 mph sustained
southwesterly surface winds (with higher gusts) have prompted a
Critical Risk of fire weather over parts of the Great
Basin/Southwest Friday into Saturday.


Ziegenfelder


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