Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
328 AM EDT Fri Jun 19 2026
Day 2
Valid 12Z Sat Jun 20 2026 - 12Z Sun Jun 21 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
THE CENTRAL PLAINS AND MISSOURI VALLEY...

...Central Plains and Missouri Valley...

A large area of heavy rain associated with a developing MCS
starting Saturday afternoon and continuing into Saturday night is
expected to bring widespread heavy rainfall across portions of the
central Plains into the Missouri Valley with the greatest threat
currently expected across southeastern Nebraska, northeastern
Kansas, and far northwestern Missouri/southwestern Iowa. Storms
are expected to initiate Saturday afternoon with peak heating over
the central High Plains and ahead of a racing shortwave crossing
the Rockies. Meanwhile, a LLJ of southeasterly flow will pump deep
Gulf moisture up the Plains through the day. This will force the
dryline to race eastward in response. The warm front associated
with the low and the dry line will uplift the deep moisture,
resulting in widespread shower and thunderstorm development. These
storms are expected to grow upscale into an expansive, organized
convective system into the evening and overnight hours that will
then track southeasterly across the risk area.

The latest deterministic guidance shows areal average rainfall
totals along the expected path of the MCS in the 2-3" range with
locally higher amounts of 4-6", more than sufficient to lead to
scattered and potentially widespread flash flooding, which has
prompted the level 3/4 Moderate Risk. As is usually the case with
convective systems the exact path and duration will be determined
by more mesoscale details than the guidance can typically pin down
at this time frame, so some areal modification and possible
expansion of the Moderate Risk will be likely over the next couple
of days. The most likely area for expansion would be further to
southeast into more of western Missouri and east-
central/southeastern Kansas. However, given the noted uncertainty
with the evolution of these types of systems at this timeframe,
have limited the extent of the risk area to also overlap where the
greatest support/confidence is shown by the ensemble
mean/probabilistic guidance.

...Eastern Texas through the Central Gulf Coast...

One more day of scattered slow-moving storms is expected on
Saturday across the Deep South between eastern TX and southern
AL/FL Panhandle. The lingering frontal boundary draped north of the
Gulf Coast will begin to lift north during the day and leave
convection widely scattered, but more focused activity is likely
during the morning hours as high pressure over the Tennessee Valley
keeps the thermal/moisture gradient rather sharp and focuses
ongoing thunderstorm activity within PWs above 2". Lingering MCV(s)
from the day 1 period across eastern TX and the Lower Mississippi
Valley could also add locations for more organized thunderstorm
activity. The soils in this region also remain extremely saturated
and sensitive to additional intense rainfall rates, leading to the
potential for scattered instances of flash flooding on Saturday and
the SLGT risk of excessive rainfall.

Snell


Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt