Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
359 AM EDT Wed Apr 23 2025
Day 1
Valid 12Z Wed Apr 23 2025 - 12Z Thu Apr 24 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE PLAINS AND THE SOUTHEAST...

Persistent Gulf moisture advecting northward through the Gulf
states over a stalled frontal boundary draped across the Southeast
will continue to produce scattered to widespread convection capable
of producing heavy rainfall. Rounds of showers and thunderstorms
will fire up along the the boundary from Texas to the Carolinas
with some training and backbuilding expected. Given there will be
very little movement of the front the storms are likely to track over
many of the same areas being impacted by ongoing showers and
storms of late, which locally increases the flash flooding risk. A
convective complex tracking east across the Hill Country during
the very early hours of Wednesday is spreading 0.5 to 1 inch/hour
rain rates along its path which may lead to isolated urban flash
flooding. Refer to WPC mesoscale precipitation discussion #160 for
more details.

The latest guidance has better confidence that the wettest areas
will likely focus over southern Nebraska and northern Kansas. This
too will be the result of an MCS or clusters of thunderstorms
developing and training multiple times over the same areas. The
Marginal remains in place as the consensus of heaviest rains on the
order of 1-2 inches (locally higher, of course) is in a portion of
Kansas and Nebraska that has largely missed out on recent heavy
rainfall, and the antecedent dry conditions should help to offset
and delay the greatest impacts from any heavy rain.

The area of the Marginal of least concern appears to be over
Oklahoma, which while seeing some scattered shower and thunderstorm
activity, should be between the MCSs/areas of more organized and
persistent convection. However, due to heavy rainfall, lower FFGs
over much of the state lower the threshold needed to achieve flash
flooding, so the Marginal is largely unchanged there.

Campbell/Wegman


Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt