Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
409 AM EDT Thu Apr 16 2026

Day 1
Valid 12Z Thu Apr 16 2026 - 12Z Fri Apr 17 2026

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

Campbell

Day 2 Valid 12Z Fri Apr 17 2026 - 12Z Sat Apr 18 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE MID-MISSISSIPPI VALLEY INTO THE SOUTHERN PLAINS...

A deep, positively-tilted longwave trough advancing into the Plains
will promote broad areas of ascent from the Southern Plains to the
Midwest. A well-defined axis of diffluence ahead of the mean
trough with several shortwaves rippling through the flow will
enhance an area of convective development within a strengthening
warm-sector environment positioned between a strong cold front over
the High Plains and a quickly advancing warm front migrating
poleward through the adjacent Mississippi and Ohio Valleys. This
environment will be rather favorable for a broad footprint for
heavy rainfall. There has been a persistent south/southwest trend
with the axis of highest QPF for several model cycles which now
focuses over northeast Oklahoma to north-central Missouri with
areal averages of 1-2 inches with isolated maximums nearing 3+
inches. The adjusted Slight Risk spans from northeast Oklahoma to
northern Illinois with the encompassing Marginal Risk from the
Oklahoma.Texas border northward to Wisconsin.

Campbell/Kleebauer

Day 3
Valid 12Z Sat Apr 18 2026 - 12Z Sun Apr 19 2026

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTH, LOWER MISSISSIPPI VALLEY AND TEXAS...

The frontal system described above will continue to advance
eastward with the trailing tail of the cold front dropping
south/southeast through Texas and the Lower Mississippi Valley.
Gulf moisture will be advecting northward into the Southern Plains
and pooling across Texas. PW values of 1.25-1.5 inches will be present
over much of eastern Texas and Louisiana during this period. Strong
convergence will lead to showers and thunderstorms focusing along
and ahead of the frontal boundary, especially for the later half of
the period. Areal average of 1 to 2 inches expected with hourly
rainfall rates greater than 1 inch/hr as well may lead to isolated
areas with flash flooding concerns. A Marginal Risk area is in
effect from South Texas to northern Mississippi.

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