550
FXUS01 KWBC 031956
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
356 PM EDT Thu Apr 03 2025

Valid 00Z Fri Apr 04 2025 - 00Z Sun Apr 06 2025

...Life-threatening, catastrophic, and potentially historic flash
flood event continues across the Lower Ohio Valley and Mid-South
to Lower Mississippi Valley...

...A couple rounds of significant severe weather expected from the
Mid-South west through the Ozarks and ArkLaTex with very large
hail and strong tornadoes possible...

...Moderate to locally heavy snow showers expected for the
Rockies, with some snow showers spreading eastward into the High
and Northern/Central Plains...

...Well above average, very warm Spring temperatures to end the
week across the Southeast with numerous record-tying/breaking
highs possible...

A powerful Spring storm system will continue to bring the threat
of life-threatening flash flooding and significant severe weather
focused on the Ohio Valley west-southwest through the Middle/Lower
Mississippi Valley, Mid-South, and ArkLaTex. A leading upper-level
shortwave within a broader large-scale trough over the
western/central U.S. and accompanying surface low pressure/frontal
system will press eastward over the Northeast Thursday night, with
a trailing cold front stretching southwestward through the
Mid-Atlantic, Ohio Valley, Mid-South, and into the Southern
Plains. The southern part of this frontal boundary is set to stall
for the next few days as a building upper-level ridge over the
Southeast keeps it stationary. The blocking pattern has also
focused deep moisture along the front, which will help to fuel
continued rounds of intense downpour-producing thunderstorms
throughout the region, but with a particular focus centered on the
Lower Ohio Valley into the Mid-South and Lower Mississippi Valley.
Storm initiation and movement roughly parallel to the boundary
will lead to repeated rounds of rainfall over the same areas,
including those already hard hit on Wednesday, leading to
significant to extreme, potentially historic, rainfall totals over
increasingly saturated soils. High Risks of Excessive Rainfall
(level 4/4) are now in effect through Saturday. Through Thursday
night, areas of eastern Arkansas into western Tennessee/Kentucky
are the most at risk for possibly widespread life-threatening
flash flooding. On Friday, the High Risk shifts west a bit to be
located from southern Missouri across much of Arkansas and the
ArkLaTex as the upper trough pivots and best moisture inflow
shifts west with it. The Lower Ohio Valley to the Mid-South and
Arkansas are under a High Risk once again on Saturday over areas
that will saturated if not already flooding by then. Moderate and
Slight Risks are in place for all three days over broader areas of
the Ohio Valley into the south-central U.S. where scattered to
numerous instances of flash flooding can be expected. This is a
catastrophic, potentially historic heavy rainfall and flash flood
event, with some locations potentially seeing rainfall amounts as
high as 10-15"+ through the weekend. The repeating rounds of heavy
rainfall each day will also raise the risk of widespread
significant river flooding, including potentially catastrophic
major flooding, in the Ozarks, portions of the Middle Mississippi
Valley, and much of the Ohio Valley.

In addition to the flash flood threat, significant severe weather
will also remain a concern for many of the same locations over the
next couple of days. Embedded shortwaves within the broader trough
will help to bring upper-level dynamic support amidst intense
low-level southerly flow and sufficient instability to support
supercells. The Storm Prediction Center has issued an Enhanced
Risk of severe weather (level 3/5) from the Mid-South west through
the ArkLaTex through Thursday night for the threat of a few
tornadoes, some of which could be strong, very large hail, and
damaging winds. A broader Slight Risk (level 2/5) extends along
the boundary from the central Appalachians southwest though the
Tennessee Valley/Mid-South and into northern Texas for the threat
of large hail, damaging winds, and a few tornadoes. On Friday, the
risk is raised to Moderate for the ArkLaTex for strong tornadoes,
very large hail, and damaging winds. Once again a broader Slight
Risk is in place from Texas through the Lower Ohio Valley. Then
Saturday, Slight to Enhanced Risks are delineated for the Lower
Mississippi Valley through the Mid-South and Ohio Valley.

A pair of upper waves and a passing cold front will help support
snow showers over the Rockies as well as bring the chance for some
wintry precipitation to the High and northern/central Plains the
next couple of days. To the north, a northern stream upper wave
dropping south from Canada and accompanying surface cold front
will bring moderate to heavy snows Thursday to the northern
Rockies, as well as a wintry mix of rain and snow spreading
eastward into portions of the northern/central Plains Thursday
into Friday. Accumulations are expected to remain light with snows
over the Plains, though a corridor of a few inches of snow could
focus in North Dakota. To the south, an upper-level shortwave in
the broader western/central U.S. trough will pass over the Four
Corners region and central/southern Rockies as an area of low
pressure in the lee of the Rockies helps to focus upslope flow
along the mountains. Moderate to locally heavy snows are expected
into Friday for the regional mountain ranges, with the potential
for some snow for portions of the High Plains along the Front
Range. The cold front to the north will also pass southward by
late Friday and into the day Saturday, bringing renewed
post-frontal upslope flow and additional heavy snow for the
mountains of the Front Range. There is also an increasing
potential for accumulating snow spreading further east across the
Raton Mesa on Friday and across portions of the southern High
Plains on Saturday.

The amplifying pattern will lead to expanding well above average,
warm Spring temperatures over portions of the eastern U.S. as the
upper-level ridge builds northward, while temperatures will remain
much cooler and below average under the upper-level trough over
most of the western/central U.S. Highs the next couple days across
the southeastern quadrant of the U.S. are forecast to be in the
80s to low 90s, with numerous record-tying/breaking highs
possible. Farther north, the Mid-Atlantic/Northeast should cool to
the 50s and 60s for highs on Friday, and a cool surface high will
take hold in the Northeast Saturday for below normal highs in the
40s. Meanwhile, forecast highs across the Plains into the Interior
West will be mostly well below average. Northern and central areas
of the Rockies and Plains should see high temperatures in the 30s
and 40s on Friday, and southern Rockies/High Plains can expect
highs that are below average by 20-25 degrees by Saturday with
actual highs falling into the 40s. The West Coast can expect
warmer, above average temperatures compared to the rest of the
West as a ridge builds northward over the region, with highs in
the 60s and 70s.


Tate/Putnam


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