Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
354 AM EDT Sat Apr 19 2025

Day 1
Valid 12Z Sat Apr 19 2025 - 12Z Sun Apr 20 2025

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FROM NORTH-
CENTRAL TEXAS THROUGH MUCH OF SOUTHERN MISSOURI...

A narrow corridor of 4 to 6+ inches of rainfall likely today
across southern Missouri to North-central Texas as thunderstorms
train and backbuild along a slow moving/stalled frontal boundary.
There has been a consistent and persistent westward trend of the
placement of the heaviest rainfall both in the model runs and the
deterministic WPC QPF. Once again the risk areas were expanded
south and west. The Moderate Risk spans from north-central Texas to
the Missouri Ozarks; which had a minor reduction in coverage out of
Illinois given the decrease in QPF from the Mid-Mississippi Valley
to Ohio. The Slight Risk was also reduced over parts of Illinois
and Indiana while extended further into central Texas. The Marginal
was trimmed southward across Illinois, Indiana and Ohio while
adjusted westward of west-central Texas.

On the north side the cold, dry northeasterly flow will be
weakening while in the warm sector there will be an ever increasing
supply of hot and humid air straight out of the Gulf being
advected northward on up to 50 kt winds across Texas and into the
frontal interface from north Texas through Oklahoma and Missouri.
An upper low ejecting from the mountains into this hot, moist
airmass will lead to robust cyclogenesis over Oklahoma by Sunday
morning.

Campbell


Day 2
Valid 12Z Sun Apr 20 2025 - 12Z Mon Apr 21 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR THE CENTRAL
PLAINS AND PORTIONS OF THE MIDDLE AND LOWER MISSISSIPPI VALLEY...

The system responsible for the scattered to widespread
heavy/excessive rainfall on Saturday will begin to accelerate to
the northeast as the upper trough begins to fill. Rainfall amounts
should not rival amounts that are expected on Saturday, but
additional rainfall on top recently flooded areas remains a
potential concern. General model consensus shows a broad footprint
of up to 1.25 inches with isolated maximums of 1.5 to 2+ inches
anywhere from eastern Nebraska to southern Minnesota and Wisconsin.
The exact location of the heaviest amounts has the greatest
uncertainty.

A Marginal Risk is in place for the Middle and Lower
Mississippi Valley and eastern portions of the Central Plains.
These areas are north and west of the most sensitive areas of the
Mississippi/Ohio River Valleys where streamflows remain high after
recent flooding. However, some rain atop recently flooded areas,
and runoff from other areas into these rivers, could exacerbate
ongoing flooding issues in some areas, so continue to monitor.

Campbell/Bann


Day 3
Valid 12Z Mon Apr 21 2025 - 12Z Tue Apr 22 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Campbell

Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt