Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
843 AM EDT Sat Apr 11 2026

Day 1
Valid 1227Z Sat Apr 11 2026 - 12Z Sun Apr 12 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHERN PLAINS...

...Central Plains...

A persistent MCS responsible for periods of excessive rainfall and
resulting flash flooding will continue through the remainder of
this morning. The 12Z TOP sounding shows as much as 1,000 J/kg of
MUCAPE, along with a saturated and nearly 8,000ft warm cloud layer
aloft, plus a highly sheared environment featuring excellent low-
level SRH in the sfc-1km layer that exceeds 250 m2/s2. The ARW has
handled this complex the best and it suggests organized
thunderstorms for at least a few more hours over northeast KS that
could expand into far northwest MO. WPC MPD #0090 has been
highlighting the threat, but with several more hours of excessive
rainfall expected to continue deeper into the day, WPC has upgraded
portions of the Central Plains to a Marginal Risk for additional
flash flooding today.

Mullinax


---Previous Discussion---

...Southern Plains...

The presence of an increasing southerly low level will transport
Gulf moisture northward and pool over the Plains and Mississippi
Valley as an upper level trough enters the West and ridging builds
over the East. Meanwhile the upper dynamics and embedded shortwave
energy will support ascent ahead of a longwave trough. At the
surface, a dry line across West Texas will help serve as an
initiating mechanism for convection in the afternoon. Strong to
severe thunderstorms are expected to fire up over the Southern and
Central High Plains, migrating eastward eventually making headway
into the adjacent Concho Valley and lower Trans Pecos. As cells
merge due to cold pool mergers and low-level jet initiation, a
large cluster of heavy rainfall will ensue through the rest of
Saturday night into Sunday morning.

General consensus maintains 2-4 inches possible from the Concho
Valley in West Texas to the Red River Valley in southern Oklahoma.
Neighborhood 24 hr QPF HREF probabilities show a strong signal for
50-80% for 2 inches for this region and 40-70% for 3 inches. A
Slight Risk for Excessive Rainfall remains in effect across
portions of the Southern Plains, especially the areas referenced
above.

...Upper Midwest and Great Lakes...

Scattered to widespread convection is expected across parts of
Wisconsin and Michigan as moisture increase along a warm front
lifting northward through the region. Areal averages of around 1
inch are still on track. Much of the region will be sensitive to
additional precipitation as there has been ongoing snow melt and
high river flows. Although it may be isolated, flash flooding
may be possible during this period. A Flood Watch remains in effect
across the Michigan U.P. and far northern Lower Michigan and
Wisconsin.

...Northeast Kansas to the Missouri/Iowa border...

Ongoing convection from overnight is producing some decent rainfall
rates from northeast Kansas to northern Missouri. Most of the
guidance show convection dying down during the morning hours and
diminished by 18Z. There is a non zero chance that there may be
very isolated heavy rainfall that could lead to localized flash
flooding.

Campbell

Day 2
Valid 12Z Sun Apr 12 2026 - 12Z Mon Apr 13 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR CENTRAL TEXAS...

...Central Texas...

Multiple rounds of strong to severe storms will persist across the
Southern/Central Plains and Lower Mississippi Valley given high
moisture presence, favorable wind shear and instability in place.
A meandering dry line across the region will provide a focus for
backbuilding cells. With limited eastward progression of the QPF
footprint expected during this period, there is a growing threat
for flash flood concerns across portions of Hill Country to the I-35
corridor south of Dallas. A Slight Risk for Excessive Rainfall is
now in effect for central Texas for the threat with a Marginal Risk
extending northeastward through Oklahoma and adjacent areas of
Kansas/Missouri/Arkansas.

...Northern Michigan...

Gulf moisture will continue to transport northward and interact
with the frontal boundary draped across the region. An additional 1
to 2 inches of rain is expected across the upper portion of the
Mitten which may expedite local snow melt and runoff. A Marginal
Risk for Excessive Rainfall remains in effect across northern
Michigan.

Campbell/Wilder

Day 3
Valid 12Z Mon Apr 13 2026 - 12Z Tue Apr 14 2026

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE UPPER MISSISSIPPI VALLEY AND UPPER GREAT LAKES REGION...

Showers and thunderstorms will persist through this period as the
warm front lifts into southern Canadian and the cold front advances
through the Northern Plains into the Upper Mississippi Valley.
Additional rainfall will maintained an elevated threat for isolated
flash flooding and speed up snow melt around the region. A Marginal
Risk remains in effect from eastern Minnesota to northern Michigan.


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