Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
358 PM EDT Tue Apr 01 2025

Valid 00Z Wed Apr 02 2025 - 00Z Fri Apr 04 2025

...Significant, life-threatening, and potentially catastrophic flash flood
event begins Wednesday for the Lower Ohio Valley and Mid-South...

...Severe weather threat shifts from the central/southern Plains this
evening to the Midwest and Middle/Lower Mississippi Valley Wednesday...

...Another late season winter storm for the Northern Plains into the Upper
Midwest/Great Lakes through Wednesday with heavy snowfall expected...

...Unsettled weather continues over the West as an upper-level trough
passes over the region...

...Critical Risk of fire weather for portions of the central/southern High
Plains and Southwest through Wednesday...  

A potent Spring storm will bring the threat of significant,
life-threatening, and potentially catastrophic flash flooding, widespread
severe weather, and impactful winter weather to portions of the
Plains/Mississippi Valley/Midwest this week. An energetic upper-level
trough will deepen over the Intermountain West as an accompanying surface
low and frontal system strengthens in the lee of the Rockies through this
afternoon and evening. As the developing surface cyclone ejects into the
central Plains, moist southerly return flow will intensify and bring
increasingly unstable air into the region. Combined with strong
atmospheric dynamics and wind fields associated with the trough and
surface low, the risk of thunderstorms and severe weather will steadily
increase across the central/southern Plains. The Storm Prediction Center
has maintained an Enhanced Risk (level 3/5) for the threat of very large
hail, damaging winds, and several tornadoes, some of which could be
strong, especially during the late evening hours. In addition, expanding
storm coverage and the potential for heavy downpours may also lead to some
isolated instances of flash flooding through tonight. Then, on Wednesday,
the progression of the system will begin to slow heading into the
Midwest/Mississippi Valley, especially with southward extent, as an
upper-level ridge builds over the southeastern U.S. More widespread storms
are expected in the warm sector ahead of the cold front with an increasing
tendency for storms to cluster/repeat over the same regions by Wednesday
evening as the progress of the cold front slows. This is most likely to
occur along an axis from the Lower Ohio Valley southwestward through the
Mid-South. Increasing moisture pooling ahead of the cold front will also
lead to more intense downpours following another day of return flow on
Thursday. A Moderate Risk of Excessive Rainfall (level 3/4) remains in
effect for the region as this will be the beginning of a multi-day
significant, life-threatening flash flood event. On Thursday, the existing
Moderate Risk was upgraded to a High Risk (level 4/4) for portions of
southeast Missouri, southern Illinois, western Kentucky, and northwest
Tennessee given increasing confidence of potentially catastrophic impacts
from flash flooding and river flooding. While the placement of the cold
front and exact axis of heaviest rainfall is likely to change somewhat as
the event nears, several inches of heavy rain are probable, with some
locations potentially seeing amounts in excess of 10" over the next 7
days. Widespread severe weather is also expected Wednesday across much of
the Midwest/Ohio Valley southwest through the Mid-South, ArkLaTex, and
North Texas. A broad Enhanced Risk covers the region for the growing
potential of very large hail, significant damaging winds, and strong
tornadoes, but the greatest threat lies from the Lower Ohio Valley to the
Middle Mississippi Valley where the Storm Prediction Center has upgraded
to a Moderate Risk (level 4/5). 

Beyond the flash flood and severe weather threat, a late-season winter
storm is also forecast in the colder air to the north of the system across
portions of the Northern Plains and Upper Midwest. Snow has already begun
and will continue to increase in coverage and intensity through this
evening, lasting through Wednesday night, as the system intensifies and
lifts northeastward through the region. An axis of heavy snow is forecast
along and to the north of the surface low track from the eastern Dakotas
east through central/northern Minnesota and into northern Wisconsin. Storm
total snowfall of 4-8 inches, locally higher, is expected. Gusty winds may
lead to areas of blowing snow and difficult travel conditions. A wintry
mix of sleet and freezing rain is expected just to the southeast of the
heavy snow from central Minnesota/Wisconsin east into the LP of Michigan.
A leading shortwave ahead of the system will also bring wintry mix to the
interior Northeast/New England on Wednesday with precipitation beginning
as snow/freezing rain before changing over to mostly rain as warmer air
reaches the region. Some light to moderate snow and ice accumulations are
possible for higher elevations and portions of northern Maine.

In the West, coastal rain, an interior lower elevation wintry mix, and
heavy higher elevation snow continue as the noted upper-level trough
slowly pivots over the region. Moderate to locally heavy rainfall will
continue along portions of the West Coast, especially along the coastal
ranges of northern California into far southern Oregon. Precipitation
across lower elevations of the interior from the Great Basin east into the
northern/central Rockies should remain very light with little to no snow
accumulations. Very heavy snowfall continues across the regional mountain
ranges, especially for the Sierra Nevada and the northern/central Rockies.
Additional snowfall totals of over foot are expected, with 1-4 feet
possible for the Sierra Nevada. Snowfall should come to an end for
California and western areas of the Great Basin by Wednesday while
lingering for the eastern Great Basin and northern/central Rockies. The
potent upper-jet accompanying the trough as it dives south and eastward
over the West and into the central U.S. will also bring very strong winds
with gusts upwards of 50-60 mph from southern California and the Southwest
east into the southern Rockies and the Plains. Warm temperatures and very
dry antecedent conditions on top of the high winds have prompted the Storm
Prediction Center to highlight a Critical Risk of fire weather conditions
for portions of the central/southern High Plains and Southwest through
Wednesday. Dust storms will also be possible. 

An amplifying pattern will bring increasingly warmer/above average
conditions across the south-central and eastern U.S. while temperatures
remain cooler and below average under the upper-level trough over the
West. High temperatures in the 70s and 80s across the Southeast and
central/southern Plains this afternoon will spread into the Midwest by
Wednesday, followed by the Eastern U.S. on Thursday. Prior to the arrival
of the unseasonable warmth, highs in the Mid-Atlantic and Northeast will
generally be near to below normal, especially with northward extent. North
of the surface low track, high temperatures will remain quite cool across
the northern Plains and Upper Great Lakes through Thursday. With respect
to seasonal averages, the coldest departures from normal across the U.S.
will generally reside along and west of the Continental Divide given
plentiful clouds and precipitation chances the next few days.


Miller/Putnam


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