Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
735 PM EDT Thu Apr 25 2024
Day 2
Valid 12Z Fri Apr 26 2024 - 12Z Sat Apr 27 2024

...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS ACROSS PORTIONS OF
THE SOUTHERN PLAINS INTO THE LOWER TO MID MISSISSIPPI VALLEY...

21Z update... Overall the setup for this period has not changed
much, just minor shifts of the QPF footprint across the Plains,
Midwest and Mississippi Valley. There will be some overlap of the
heavy rains from the Day 1 period and where some of the higher
amounts are expected for this period, particularly across Missouri,
Oklahoma and Arkansas. This will elevate the threat for local
flooding concerns. Minor reshaping of the Slight Risk to a more
southwest-northeast orientation was made with this update along
with an expansion into east-central Missouri.

Campbell

In what is shaping up to be an active stretch of excessive
rainfall potential, Friday may end up being a relative minimum of
flash flood impacts. The first system will be rapidly ejecting
northeast across the Plains and upper MS Valley. Given the quick
forward motion and the fact that the system will be moving east of
the stronger instability with time, tend to think any flash flood
risk will stay localized in nature from the central/northern
Plains into the upper Midwest.

The southern extent of the system may pose a slightly greater flash
flood risk, but even this remains uncertain. Convection should be
ongoing Friday morning across portions of TX/OK/AR/MO, although the
intensity and organization of this activity remains unclear. The
convection will be outrunning the surface front by this time
resulting in a gradual weakening of lower level convergence. In
the upper levels the forcing is also on a decline, so quite
possible activity is weakening Friday. However with plenty of
moisture and instability in place, and little reason for much
eastward progression of convection...any activity that is able to
persist and/or intensify during the day could end up pretty slow
moving and thus capable of producing flash flooding. Thus opted to
maintain a Slight risk from northeast TX into southwest MO to
account for this threat...while also accounting for the fact that
some of these areas may be more sensitive depending on the rainfall
that occurs Thursday and Thursday night. Also worth noting our
machine learning ERO also has elevated probabilities over
approximately this same area...likely indicative of the lingering
favorable ingredients in place.

Chenard