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

Valid 12Z Thu Apr 03 2025 - 12Z Sat Apr 05 2025

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

...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 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 continue eastward over the Great Lakes
and Northeast today, with a trailing cold front stretching southwestward
through the Mid-Atlantic, Ohio Valley, Mid-South, and into the Southern
Plains. A building upper-level ridge over the Southeast has brought the
progress of this frontal boundary to a halt overnight, with the boundary
expected to remain quasi-stationary through the region over the next few
days. The blocking pattern has also focused southerly flow of deep
boundary layer moisture from the Gulf 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. 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 rainfall totals over increasingly saturated soils.
A High Risk of Excessive Rainfall (level 4/4) is in effect Thursday from
southwestern Kentucky into western Tennessee and northeastern Arkansas
where the greatest threat for numerous instances of life-threatening flash
flooding exists following heavy rainfall over the same areas Wednesday. A
broader Moderate Risk (level 3/4) stretches from the Lower Ohio Valley
southwest through the Mid-South with a Slight Risk (level 2/4) across the
broader Ohio Valley southwest to the ArkLaTex where additional scattered
to numerous instances of flash flooding are possible. Another Moderate
Risk is in effect on Friday with the focus shifting a bit northwestward
over the Middle Mississippi Valley southwest through the ArkLaTex, areas
that have not been as hard hit compared to the Lower Ohio
Valley/Mid-South, but are still expected to see significant heavy rainfall
totals and scattered to numerous instances of flash flooding. A Slight
Risk extends further northeast towards the Great Lakes as well as
southwest into portions of the southern Plains where additional scattered
instances of flash flooding will be possible. Then, on Saturday, another
High Risk is in effect as the focus shifts back towards the hard hit Lower
Ohio Valley/Mid-South. 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 additional
rounds of heavy rainfall each day will also raise the risk of catastrophic
river flooding from western Kentucky into northwest Tennessee, and
widespread significant river flooding from the Ozarks/ArkLaTex through the
Lower Ohio Valley. Communities in the region should prepare for possible
long duration and severe disruptions to daily life.

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. Embeded 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 Thursday 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 Mid-Atlantic southwest though the Tennessee Valley/Mid-South and into
northern Texas for the threat of large hail, damaging winds, and a few
tornadoes. An Enhanced Risk is also in place Friday across the
Ozarks/ArkLaTex as another round of storms will bring yet another threat
for a few tornadoes, including strong tornadoes, very large hail, and
damaging winds. A Slight Risk extends from the Middle/Lower Mississippi
Valley southwest through northern and central Texas mainly for the threat
of large hail and damaging winds.

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 any
snows over the Plains. 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 Thursday 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. Elsewhere, some showers
and thunderstorms are expected across the Northeast Thursday as the lead
system passes through the region. Wintry precipitation will remain
possible further north into northern Maine, with some light snow and ice
accumulations possible. Some lingering snow showers are expected Thursday
over portions of the western Great Basin and into the Sierra Nevada, with
rain showers for southern California.

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. Forecast highs the the next couple days from southern
Texas east through the Lower Mississippi Valley and into the Southeast
will be in the 80s to low 90s, with numerous record-tying/breaking highs
possible. Well above average temperatures are also forecast from the Lower
Great Lakes east into the Mid-Atlantic/Northeast Thursday as highs rise
into the 60s, 70s, and low 80s before a cold front brings more seasonable
temperature mainly in the 60s Friday. Forecast highs from the
Northern/Central Plains into the Interior West will be mostly well below
average, with 30s and 40s expected. Areas of the Southern Plains outside
of south Texas will cool from the 60s Thursday to the 50s on Friday, while
the Desert Southwest will see highs mainly in the 60s to low 70s. The West
Coast will see warmer, above average temperatures compared to the rest of
the West as a ridge builds northward over the region, with highs in the
60s.

Putnam 

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