Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1205 PM EDT Tue Apr 14 2026

Day 1
Valid 16Z Tue Apr 14 2026 - 12Z Wed Apr 15 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS THE CENTRAL
L.P. OF MICHIGAN,SOUTHEAST WISCONSIN, AND THE OHIO VALLEY...

... Ohio Valley...

16Z Update: The Slight Risk for Excessive Rainfall was expanded
farther south to include central Illinois to central Indiana.Radar
and surface observations show an outflow boundary lingering across
the region from early morning showers and thunderstorms that may be
a focal point for locally heavy rainfall this afternoon and
evening. The RRFS and ARW model camps in particular are
highlighting this region with QPF maxima in the 2-5 inch range.
High seasonable PWATS and abundant instability also support the
potential for high hourly rainfall rates.

...Wisconsin and Michigan...

16z Update:

The forecast continues to support the risk for flash
flooding as storms are expected to form along a stationary boundary
over Wisconsin and then congeal into a line of storms that
progresses southeastward into Michigan. The low level jet will
transport moisture orthogonal to a stationary boundary across the
region with the training of storms possible. Most of the area
remains at near or above record spring rainfall and soils are
fairly saturated. Cells capable of 1.5-2"/hr rates and localized
totals of 2-3+" suggest the placement of a Slight Risk of Excessive
Rainfall from southern Wisconsin to eastern Michigan.

...Previous Discussion...

A Slight Risk for excessive rainfall remains
in effect for portions of the Great Lakes region. A
shortwave/vorticity center lifting out over the mean ridge in the
Great Lakes region will drive stronger confluence of the low level
jet across Iowa to trigger another round of strong to severe
thunderstorms Tuesday evening. Overall deep layer steering flow and
fairly orthogonal ascent over boundary should help to focus a
similar west to east (WNW to ENE) oriented axis of training
thunderstorms. Upper-level dual jet couplet will further enhance
up-scale growth to a broader complex to maintain through the
overnight period. Most of the area remains at near or above record
spring rainfall and soils are fairly saturated, so with cells
capable of 1.5-2"/hr rates and localized totals of 2-3+" suggest
the placement of a Slight Risk of Excessive Rainfall across
portions of eastern WI and central MI (along and north of I-94).

... Lower Trans-Pecos/Big Bend...

16 Update:

Latest model guidance indicates a higher QPF maxima across the
Lower Trans-Pecos region into the Big Bend as storms fire along the
dry line in presence of a seasonally moist environment. HREF 24
hour QPF neighborhood probabilities are around 50-70% for 2 inches
and 10-20% probabilities for 3 hour QPF exceeding flash flood
guidance. A Marginal Risk was maintained, but this area will be a
focus for locally heavy rainfall.

...Oklahoma and Kansas...

16z Update: Another targeted area for heavy rainfall will be span
south of the Norman area, northeastward into the Tulsa metro and
southern Kansas. Hi-res guidance indicates multiple rounds of
storms could traverse this region as storms fire along the dry line
boundary and south of a stationary front in Kansas. HREF 24 hour
QPF probabilities exceeding 2 inches are fairly high (50-70%) and
20-40% for exceeding 3 inches.

...Previous Discussion...
A steady stream of PW values of 1.25 to
1.5 inches will be advecting northward through the Southern/Central
Plains nearly parallel to the dryline. This will be conducive for
slow storm motion with locally heavy rainfall. Consensus suggests 3
to 4 inches possible within the isolated cells. The Marginal Risk
area is connected to the area of concern over the Great Lakes and
just note the coverage will decrease northward along the dry-line.

Campbell/Gallina


Day 2
Valid 12Z Wed Apr 15 2026 - 12Z Thu Apr 16 2026

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FROM TEXAS TO
THE UPPER MIDWEST/GREAT LAKES REGION...

The surface to mid-level environment remains very similar to the
prior 3 days, with a stark dry line extending from the Pecos River
Valley across the Southern Plains into the Upper Mississippi
Valley. During this period the longwave trough will finally be
making progress toward the Central Plains albeit as it begins to
weaken and the deep layer moisture axis and instability shift
slightly eastward. Thunderstorms are expected to break out with
hourly rates pulsing up to 2 inches/hr. Some locations ahead or
along the frontal boundary may receive over 3 inches between the
Ozarks Plateau and northeast Texas.

Further north, the environment over the Midwest/Great Lakes region
will have notably less moisture and instability present then the
days prior, however additional rains will maintain an elevated
threat for localized flooding over the hydrologically
sensitive/saturated areas of the northern Great Lakes region. The
most favorable location for appreciable precipitation will be from
northeast Illinois to souther Michigan. The Marginal Risk area was
maintained and in spans from northeast Texas northward to
Wisconsin/Lower Michigan and east to western New Yorks and
Pennsylvania.

Campbell/Gallina

Day 3
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 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