FOUS30 KWBC 250622
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
222 AM EDT Wed Mar 25 2026

Day 1
Valid 12Z Wed Mar 25 2026 - 12Z Thu Mar 26 2026

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

Wegman


Day 2
Valid 12Z Thu Mar 26 2026 - 12Z Fri Mar 27 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE MIDWEST AND UPPER OHIO VALLEY...

Only minor tweaks were needed for the new Day 2 forecast this
morning. The latest guidance, including some of the longer-range
CAMs, suggests that there is a greater chance for training showers
and thunderstorms Thursday evening and Thursday night across
portions of northern Indiana and Ohio. A series of waves of showers
and storms will race eastward along the interface of a very strong
southward-moving cold front. A zonal upper level jet streak across 
Lake Superior will max out around 150 kt 00Z Friday. Meanwhile 
moisture advection will allow PWATs to creep above 1.25 inches and 
dew points to spike into the 60s. Instability in the longer-range 
guidance has also nudged higher, into the 1,000 to 1,500 J/kg range
of MUCAPE. While organized convection appears likely given 
favorable instability and shear profiles, the fast motion of the 
storms will remain the primary factor limiting the flash flooding 
threat. Thus, as regards flooding potential, with somewhat better
environmental parameters than 24 hours ago but still dry soils in 
most areas, especially into Illinois, the area remains under a 
solid Marginal Risk. The greatest threat of isolated instances of 
flash flooding remains into the urban centers. Since most of the 
showers and storms will be occurring overnight Thursday night in 
the Marginal Risk area, any flooding will pose a heightened danger 
due to lack of visibility. 

Wegman

Day 3
Valid 12Z Fri Mar 27 2026 - 12Z Sat Mar 28 2026

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

Wegman
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