927
FXUS01 KWBC 040810
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
410 AM EDT Fri Apr 04 2025

Valid 12Z Fri Apr 04 2025 - 12Z 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...

...Additional episodes 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 into the High Plains
through Saturday...

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

Several developing waves of low pressure acting on a stalling
frontal boundary will continue to be the focus for the threat of
life-threatening flash flooding and significant severe weather
from the Ohio Valley west-southwest through the Middle/Lower
Mississippi Valley, Mid-South, and ArkLaTex the next couple of
days. Deep moisture pooling along the front combined with
impressive dynamics will set the stage for persistent rounds of
intense thunderstorms capable of producing torrential downpours
throughout the region. This will especially be the case for the
Lower Ohio Valley into the Mid-South and Lower Mississippi Valley,
where the necessary ingredients of moisture, instability, forcing,
and wind shear best overlap. Storm initiation and movement roughly
parallel to the boundary will lead to repeated rounds of heavy
rainfall over the same areas, leading to significant to extreme,
potentially historic, rainfall totals over increasingly saturated
soils. High Risks of Excessive Rainfall (level 4/4) remain in
effect through Saturday, highlighting an increasingly dangerous
and life-threatening situation. Outside of the High Risk, Moderate
and Slight Risks also continue to be in place over broader areas
of the Ohio Valley into the south-central U.S. through Saturday
where scattered to numerous instances of flash flooding can be
expected. As has been said repeatedly for the last several days,
this has the makings of 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.
Thankfully, the heaviest rainfall should ease somewhat for the
hardest hit areas on Sunday as the frontal boundary finally begins
to push eastward into the Southeast and Mid-Atlantic; however,
major river flooding is likely to continue into early next week.
With the front on the move, the focus for heavy rainfall shifts
eastward into parts of the Carolinas southward to the Central Gulf
Coast to round out the weekend. A Slight Risk (level 2/4) remains
in effect as a result.

In addition to the flash flood threat, additional bouts of
significant severe weather will also be in play for many of the
same locations through the weekend. The same ingredients of
moisture, instability, forcing, and wind shear that are conducive
to intense downpour producing thunderstorms are also supportive of
supercells and severe weather. The Storm Prediction Center has
issued a Moderate Risk (level 4/5) for Friday from the ArkLaTex
into southeast Missouri for strong tornadoes, very large hail, and
damaging winds. A broader Slight Risk is in place from Texas
through the Lower Ohio Valley. On Saturday, Slight to Enhanced
Risks are delineated for the Lower Mississippi Valley through the
Mid-South and Ohio Valley, with severe thunderstorms capable of
producing strong tornadoes, very large hail, and damaging wind
gusts above 70 mph. Similar to the flash flood threat, the severe
weather risk shifts eastward into parts of the Mid-Atlantic,
Southeast, and southern Appalachians on Sunday, with the Storm
Prediction Center issuing a Slight Risk for the potential for
damaging winds and possibly a few tornadoes.

Farther west, a passing cold front will help support snow showers
over the Rockies as well as portions of the High Plains the next
couple of days. 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 area of low pressure
in the lee of the Rockies will help to focus upslope flow along
the mountains, resulting in moderate to locally heavy snows for
the regional mountain ranges on Friday, 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 to spread across portions of New Mexico and into
the southern High Plains later Friday into Saturday. Drier weather
returns on Sunday as high pressure takes control.

The highly amplified flow pattern will lead to well above average
temperatures across the Southeast as an upper-level ridge
dominates the region. Meanwhile, 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
Southeast are forecast to be in the 80s to low 90s, with numerous
record-tying/breaking highs possible. Farther north, the
Mid-Atlantic/Northeast will 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. Some wintry weather
can`t be ruled out across northern New England on Sunday either
given persistently cool temperatures on the north side of the
front. 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 The West will continue
to warm up on Sunday while cooler air across the Plains spreads
eastward into the Ohio Valley, the Mid-South, and the Lower
Mississippi Valley.


Miller


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