Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
857 PM EDT Sat Jun 14 2025
Day 1
Valid 01Z Sun Jun 15 2025 - 12Z Sun Jun 15 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
OKLAHOMA AND THE MID ATLANTIC...

...Mid-Atlantic...
Convection moving southeast along a stationary front will result
in isolated to scattered flash flooding this evening across
portions of northern and eastern VA. Given the location of the
front and instability gradient it appears that the heaviest
rainfall rates will remain in VA, and thus we were able to take DC
and MD out of the Slight risk. High PWs and slow cell
motions/mergers near the front will allow for high rainfall rates
and isolated amounts exceeding 3" across portions of northern and
eastern VA.

...Oklahoma...
At least some flash flooding appears likely overnight into early
Sunday across portions of OK. In the mid levels we have a well
defined shortwave across KS, which will slowly drift southward into
OK tonight. To the south of this feature increasing low level
moisture transport/convergence will interact with a highly unstable
airmass. Convection will expand in coverage by later this evening,
and activity should initially be slow moving and exhibit
backbuilding characteristics. This will allow for areas of
excessive rainfall, with recent HRRR and RRFS runs depicting a
swath of 3-5" of rainfall, and both the 18z HREF and REFS showing
over a 40% chance of locally exceeding 5". By later tonight
convection will grow upscale and likely develop a stronger cold
pool resulting in a southward acceleration of convection. High
rainfall rates could still result in a localized flash flood threat
after this faster southward propagation occurs...but the coverage
and magnitude of the threat should be lower by then. Thus the
greater risk is this evening into tonight when convection should
be slower moving and backbuilding...and do consider this a higher
end Slight risk centered over central OK. Scattered flash flooding
is probable, some of which could be locally significant.

...Upper Midwest...
A Marginal risk was maintained across portions of far southeast SD
into IA. Seeing a recent expansion of slow moving convection near
a stationary front which could result in localized flash flooding
through the evening hours.

...Central Montana...
Convection over portions of central and eastern MT will continue
to pose an isolated flash flood risk into the overnight hours.
Recent HRRR runs are likely under doing rainfall amounts over this
area. Recent RRFS runs may be overdone, but likely do have a
better handle on the repeat nature of convection that should
continue into tonight. Impressive CAPE/Shear profiles will
continue to support convective clusters and supercells, and with
PWs over 1", heavy rainfall rates will be likely. Localized
rainfall upwards of 2-3" is possible through the overnight hours.

Chenard


Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt