977
FXUS01 KWBC 200719
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
318 AM EDT Sun Apr 20 2025

Valid 12Z Sun Apr 20 2025 - 12Z Tue Apr 22 2025

...Light to moderate snow over parts of the Cascades, Northern
Intermountain Region, Northern Rockies, and Upper Great Lakes on
Sunday and Monday...

...There is a Slight Risk of excessive rainfall over parts of the
Middle Mississippi Valley and the Southern Plains on Sunday...

...There is an Enhanced Risk of severe thunderstorms over parts of
the Middle/Lower Mississippi Valley on Sunday...

A wave of low pressure over the Southern Plains on Sunday will
move northeastward to into western Quebec, Canada, by Tuesday. The
associated front will move from the Southern Plains to the
Northeast to the Mid-Atlantic and then southwestward to the
Southern Plains by Tuesday as well. Moisture from the Gulf of
America will stream northward over the Plains and intersect with
the boundary, producing showers and severe thunderstorms over the
Middle/Lower Mississippi Valley. Therefore, the SPC has issued an
Enhanced Risk (level 3/5) of severe thunderstorms over the
Middle/Lower Mississippi Valley through Monday morning.  The
hazards associated with these thunderstorms are frequent
lightning, severe thunderstorm wind gusts, hail, and a few
tornadoes.  Furthermore, there is an added threat of EF 2 to EF 5
tornados over the Middle/Lower Mississippi Valley.

In addition, the showers and thunderstorms will produce heavy rain
over parts of the Middle/Lower Mississippi Valley and the Southern
Plains on Sunday. Therefore, the WPC has issued a Slight Risk
(level 2/4) of excessive rainfall over parts of the Middle/Lower
Mississippi Valley and the Southern Plains through Monday 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.

On Monday, the threat of severe thunderstorms and excessive
rainfall reduces. However, showers and thunderstorms will continue
along and ahead of the front from the Great Lakes/Ohio Valley into
the Tennessee Valley, Lower Mississippi Valley, and the Western
Gulf Coast. The threat of excessive rainfall associated with these
storms is not expected.

Early Monday morning, wet snow will develop near the western third
of Lake Superior. By Monday evening, the swath of wet snow will
move eastward over parts of the Upper Peninsulas of Michigan,
moving into Canada by Tuesday morning. Rain with embedded
thunderstorms will move into the Northeast overnight Monday.
Showers and thunderstorms will continue along the front overnight
Monday into Tuesday morning from parts of the eastern
Ohio/Tennessee Valleys into the Lower Mississippi Valley and
Central Gulf Coast.

Meanwhile, on Sunday, upper-level energy will move onshore over
the Pacific Northwest overnight, developing a front over the
Northern Intermountain Region. The energy will produce rain and
highest-elevation snow over parts of the Northwest into the
Northern Intermountain Region and the Northern Rockies.

On Monday, the front consolidates over the Northern
Rockies/Northern Intermountain Region and moves eastward to the
Northern/Central Plains across the Central Rockies into the Great
Basin by Tuesday. The system will create highest-elevation snow
and lower-elevation rain over parts of the Northern Intermountain
Region/Northern Rockies. Rain will begin to develop over parts of
the Northern High Plains on Monday afternoon into evening. The
rain will move into parts of the Northern Plains/Upper Mississippi
Valley by Tuesday morning.


Ziegenfelder


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