Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Wed Apr 02 2025

Valid 12Z Wed Apr 02 2025 - 12Z Fri Apr 04 2025

...Life-threatening, potentially historic flash flood event begins
Wednesday for the Lower Ohio Valley and Mid-South...

...Tornado outbreak expected Wednesday for the Mid-South with multiple
intense tornadoes possible...

...Late season winter storm continues Wednesday for portions of the
Northern Plains/Upper Midwest 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 Wednesday...  

A powerful Spring storm system will bring a barrage of life-threatening
weather including flash flooding and strong tornadoes to portions of the
Lower Ohio Valley and Mid-South Wednesday, with the flash flood threat
only the beginning of a multi-day catastrophic and potentially historic
event. A deepening upper-level trough and accompanying strong low
pressure/frontal system over the Plains this morning will push eastward
through the Midwest, Mississippi Valley, and southern Plains Wednesday.
Extremely impressive dynamics given very strong upper-level and
lower-level wind fields, as well as a deep influx of boundary layer
moisture flowing northward from the Gulf, will help support a broad warm
sector featuring widespread, intense thunderstorms stretching from the
Great Lakes southwest through the Middle Mississippi/Lower Ohio Valleys,
Mid-South, ArkLaTex, and Southern Plains. The Storm Prediction Center
(SPC) has introduced a High Risk (level 5/5) of severe weather across
portions of the Mid-South where the most favorable overlap of strong
upper- and lower-level shear and instability may lead to an outbreak of
tornadoes, including multiple intense tornadoes, as well as very large
hail and significant damaging winds. A broader at least Enhanced level
(3/5) severe threat covers the rest of the region where a more scattered
but still significant threat of tornadoes, large hail, and damaging winds
exists. Unfortunately, this severe threat will be compounded by the
beginning of a life-threatening flash flood event. Strengthening
upper-level ridging to the east will help to slow the progression of the
cold front through the day Wednesday, increasing the chance of repeated
rounds of storms as they begin to move more parallel to the stalling
boundary. The blocked flow will also help to maintain a supply of
plentiful Gulf moisture helping to foster very-efficient, intense downpour
producing storms. There is a Moderate Risk of Excessive Rainfall (level
3/4) Wednesday overlapping much of the SPC High Risk from the Lower Ohio
Valley southwestward into the Mid-South where the greatest potential
exists for several inches of rainfall and scattered to numerous instances
of flash flooding through the evening and overnight hours. The front will
become nearly stationary across the region Thursday leading to an even
greater risk of significant heavy rainfall totals, with the probability of
more than 6" of rain over the two day period at 40-60%. The repeated
rounds of rainfall will lead to increasingly saturated soils, and could
bring additional rainfall over areas already experiencing flooding. For
these reasons, another Moderate Risk is in place Thursday for the Lower
Ohio Valley/Mid South to the ArkLaTex with an embedded High Risk (level
4/4) for western Kentucky, the Missouri Bootheel, northwestern Tennessee,
and extreme northeastern Arkansas where widespread, life-threatening flash
flooding is expected. The front will remain stalled into the weekend with
Moderate Risks already in place for Friday and Saturday. This event will
bring potentially historic amounts of rainfall, with some locations
possibly seeing as much as 10-15"+ of rain through the weekend.
Communities throughout the area should prepare now for the possibility of
long duration and severe disruptions to daily life given the expected
extreme rainfall and flood risk. Additional severe thunderstorms are also
expected on Thursday from the Mid-Atlantic southwest through the
Ohio/Tennessee Valleys and into the Southern Plains, with the SPC
maintaining a Slight Risk (level 2/5) for the threat of damaging winds,
large hail, and a few tornadoes.

Meanwhile, a winter storm continues Wednesday in the colder airmass north
of the system, with a band of heavy snow forecast along and to the north
of the surface low track from the eastern Dakotas into northern Minnesota.
Additional snowfall totals of 4-8", locally higher, are expected, with the
heaviest totals most likely along the northern shore of Lake Superior.
Gusty winds may lead to areas of blowing snow and very difficult travel
conditions. A wintry mix of snow, sleet, and freezing rain is expected
just to the southeast of the heavy snow from central Minnesota east into
northern Wisconsin and Michigan through at least Wednesday morning. These
areas of wintry precipitation are expected to transition over to rain and
even some thunderstorms as a warm front lifts northward during the day
Wednesday. A leading shortwave ahead of the system will also bring wintry
precipitation to areas of the interior Northeast/New England Wednesday,
with some light to moderate snow and ice accumulations possible for higher
mountain elevations and portions of northern Maine.

Wintry weather continues across much of the Interior West as embedded
perturbations round the broad upper-level trough over the region. Some
moderate snow totals will be possible for higher elevations of the
mountain ranges across the Pacific Northwest, Great Basin,
northern/central Rockies, and Four Corners region Wednesday. Western areas
will see the snow taper off into Thursday while the focus shifts to the
northern/central Rockies and Four Corners region. A frontal passage across
the northern Rockies and an area of low pressure east of the central
Rockies will help to enhance upslope flow and bring some heavier snow
totals to the mountains, with some snow also expected for adjacent
portions of the northern/central High Plains. Elsewhere, another day of
strong, gusty winds and low humidity across portions of the southern High
Plains and Southwest has prompted a Critical Risk of fire weather (level
2/3) from the SPC. 

An amplifying pattern with mean ridging building over the eastern U.S. and
the noted troughing over the central/western U.S. will favor warmer, much
above average temperatures to the east and cooler, much below average
temperatures to the west through at least mid-week. Some of the greatest
anomalies will be from the Southern Plains eastward through the Southeast,
where highs into the 80s and low 90s may reach daily record-tying/breaking
levels. Well above average highs into the 70s to low 80s for the Midwest
Wednesday will fall into the 50s and 60s Thursday following a cold front
passage. Highs in the 50s and 60s for the Mid-Atlantic/Northeast on
Wednesday will warm into the mid-60s to low 80s on Thursday as the ridge
builds northward. Areas of the Central/Northern Plains will remain cooler
behind the cold front with highs ranging from the mid-30s to the mid-50s.
In the West, forecast highs generally range from the 40s in the Interior
West, the 50s in the Pacific Northwest, the 50s and 60s in California, and
the 60s to low 70s in the Desert Southwest.

Putnam 

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