Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
302 PM EDT Wed Jun 3 2026
Day 2
Valid 12Z Thu Jun 04 2026 - 12Z Fri Jun 05 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
EASTERN NEBRASKA AND WESTERN IOWA...

...21Z Outlook Update...
A Slight Risk was introduced for portions of eastern Nebraska and
western Iowa for this update. Models are in general concensus that
a weak mid-level wave will track northeastward from Kansas during
the afternoon and evening hours. Convection will become scattered
to widespread across the Slight Risk area as low-level flow
increases downstream of a surface dryline and low over central
NE/KS. Some negatives are apparent in the overall flash flood
scenario, including modest/dry soil moistures and some lingering
uncertainty with respect to specific axes of heaviest rainfall.
Nevertheless, areas of 2-4 inch rainfall totals are likely --
locally higher where convective training/backbuilding can
materialize. Flash flood could occur on an isolated to scattered
basis in that regime.

Elsewhere, the Marginal Risk in eastern South Dakota has been
expanded northward and westward across the remainder of the state.
Scattered storms should develop in western South Dakota (where FFGs
are locally low) and migrate eastward, focusing along a surface
front in northeastern portions of the state. Lingering uncertainty
regarding the extent of convection precludes a Slight Risk upgrade
for that area in this outlook.

Some consideration for removal of Marginal Risk was considered for
portions of Oklahoma. Convective coverage seems to be a mitigating
factor for flash flood potential in that area. The remainder of
Marginal Risk areas were kept in place for this outlook, with
scattered thunderstorm activity expected across southern New
Mexico, west Texas, and near populated areas of southeastern
Florida.

See the previous discussion below for more details.

Cook

...Previous Discussion...

...Plains to Upper Midwest...
The cold front is expected to set up across Minnesota into the
Plains during the period, acting as the focus for organized
convection. A ramp up in the low-level jet late in the period will
likely be the primary concern for training/repeating rounds of
heavy rainfall as daytime convection should be mainly progressive
and more discrete in nature. The deterministic guidance remains
disperse and ensemble probabilities low to provide confidence for
any upgrade to Slight Risk at this time, but areas from southwest
Minnesota into portions of Iowa and eastern South Dakota are of
concern. For now, the Marginal Risk was maintained and adjusted to
the latest trends, trimming some from the western to northern
boundary.

Further south into the Plains and Texas, the continued moist
southeasterly flow and approaching mid level system out of Mexico
will bring a greater coverage of thunderstorms and the threat of
locally heavy rainfall. Overall organization of the convection is
expected to be on the lower side, but the PW anomalies support
potential for locally intense rain rates and the Marginal Risk.

...South Florida...
Frontal boundary stalling in the vicinity of the area will remain
the focus for scattered to numerous showers and thunderstorms
capable of producing intense rain rates and locally heavy rainfall
over the highly urbanized corridor. The risk for Thursday shifts a
bit further south across South Florida, mainly centering across the
Miami metro.

Taylor


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