FOUS30 KWBC 270049
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
849 PM EDT Thu Mar 26 2026

Day 1
Valid 01Z Fri Mar 27 2026 - 12Z Fri Mar 27 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
OHIO THROUGH NORTHERN WEST VIRGINIA AND WESTERN PENNSYLVANIA...

Late afternoon/early evening radar imagery was showing increase
coverage and increasing rainfall rates from Illinois eastward into
southern New York. The axis of a 150 to 175 knot upper level jet
over the Great Lakes was propagating eastward into part of
Quebec...spreading subtle but important upper level difluence over
a region of warm advection and moisture transport into the area and
where upper layers of the soils were already at/near saturation.

With precipitable water values expected to peak close to 1.5 inches
over parts of the Ohio Valley this evening...aided by the support
in the upper levels...the area from Ohio into parts of Pennsylvania
and southern New York have the best chances for some locally
intense rainfall rates. Given at least some overlap with where rain
has fallen recently and suppressed values of Flash Flood
Guidance...saw little reason to make more than cosmetic changes to
the Slight Risk area of the Marginal Risk area that covered areas
to the east.

There are mixed signals about the potential for excessive rainfall
farther west into portions Illinois and Indiana. Better moisture
flux convergence along outflow boundaries from on-going convection
may shunt the best instability south of the model forecasts. On
the other hand....some training is possible where the resulting
boundary aligns with the steering flow. Considering the
uncertainty...made no changes to the Marginal Risk area there.

Bann


Day 2
Valid 12Z Fri Mar 27 2026 - 12Z Sat Mar 28 2026

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

Cook/Wegman

Day 3
Valid 12Z Sat Mar 28 2026 - 12Z Sun Mar 29 2026

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

Cook/Wegman


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