Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
756 PM EDT Sat Jul 25 2026
Day 1
Valid 01Z Sun Jul 26 2026 - 12Z Sun Jul 26 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE SAVANNAH
RIVER VALLEY AND SOUTHWEST...

...Southeast through the Lower Mississippi and Tennessee Valleys...
Deep moisture will continue to pool along and near a stalled
frontal boundary, has led to extensive moisture from the southern
Appalachians across SC. A couple rounds of heavy rainfall are
expected -- one early across SC and one later on in and near the
Southern Appalachians over lower flash flood guidance/more rugged
terrain -- led to a rearrangement of the Slight Risk area across
the region. Hourly amounts to 2.5" can't be ruled out.

Scattered thunderstorms across Florida early, and then near the
Southwest coast and Keys late, could also cause localized heavy
rain. Reconfigured the Marginal Risk area somewhat to account for
the 18z HREF/12z REFS probabilities in this area.


...Southwest...
Monsoonal moisture/instability has led to convection across the
region this afternoon. An MCV in the vicinity still appears to be
a key player in enhancing the rainfall which leads to
greater/higher rain rates. Based on radar reflectivity/HREF and
REFS probabilities of 0.5"+ through 12z, some reductions were made
to the Marginal and Slight Risk areas across CO and NM while the
Marginal Risk area was expanded into the Lower Deserts/towards the
Lower CO River where an outflow boundary and some preceding
convection could lead to cell mergers early this evening.


...South Dakota...
Convection across the state hasn't shown much alignment as of yet,
but there is some risk for repeat convection in the near term based
on recent radar reflectivity data. The region has been dry, so
left out any risk areas for the time being. Isolated flash flooding
can't be ruled out completely if cells manage to train/align.

Roth


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