Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
339 AM EDT Wed Apr 2 2025
Day 3
Valid 12Z Fri Apr 04 2025 - 12Z Sat Apr 05 2025

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR A LARGE
PORTION OF THE LOWER AND MID-MISSISSIPPI VALLEYS...

The final surface wave within the atmospheric parade across the
Southern Plains to Mississippi Valley will show itself by late-
Friday morning through the remainder of the period. This wave will
likely be the strongest of the 3 allowing a much more amplified
surface evolution that will shift the focus of heavier precip
further northwest while also providing some vigor in the overall
QPF distribution. The trend the past 24 hrs is for a zone of
significant (3-6+") totals to be recognized across portions of the
Southern Plains up through the Ozarks and Mid-Mississippi Valley
of Missouri, spanning as far north as south-central Illinois. When
assessing the theta_e environment, there is a noticeable push north
of more modestly unstable air with the most pertinent area of
available instability situated across southern MO down through AR,
southeastern OK, and even northeastern TX. A sharp uptick in
regional PWATs with deviations between +2.5-3.5 anomaly-wise are
forecast within that zone correlating with a substantial rise in
area convection blossoming late Friday afternoon, onward. This
setup is fortunately further west compared to the previous periods,
so the overlap of the heaviest rainfall is not anticipated to be
as problematic as the previous period.

Having said that, the pattern will yield high precip totals due to
widespread convective schema, falling over some areas that will
have seen appreciable rain, and over other areas that are more
prone to flooding due to complex terrain situated over the Ozarks.
The pattern is such that several areas from northeast of DFW up
through IL will see rainfall amounts of 3-6" with locally higher
beginning Friday afternoon with the heaviest rainfall likely to
occur by the evening with the implementation of yet another LLJ
structure thanks to the surface wave mentioned previously. Further
to the west, another closed upper reflection across the Southwest
U.S. will only entice greater upper forcing within a broad axis of
difluence situated over the Plains. This setup is more privy to
convection forming as far west as the Western Rolling Plains of TX
to points east and northeast. Even there, modest 1-2" with locally
higher totals are forecast in-of those zones. As a result, there
was a general expansion of the Slight Risk further southwest into
Central TX, an expansion of the Moderate Risk to include the
eastern Red River Basin up through the southeast half of Missouri
into southern Illinois, and a high-end Moderate impacting
southeastern OK up through western AR and much of southern and
southeast MO. The threat of widespread flash flooding is
increasing for areas within the Moderate risk and aforementioned
higher-end Moderate designation. Be sure to stay up to date for the
latest changes as we move through the remainder of the week as this
pattern remains very active and prone to significant life-
threatening flash flood concerns.

Kleebauer

Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt