Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
337 AM EDT Fri Aug 7 2026
Day 2
Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR THE
SOUTHWEST, PORTIONS OF THE MIDWEST, AND MUCH OF THE EASTERN
SEABOARD...

Monsoonal moisture across the Southwest will continue on Saturday,
especially across Arizona. As usual, the greatest rainfall will be
along the Mexican border where the Gulf of California's influence
is greatest, as well as along the Mogollon Rim. There appears to be
little rain in between in the populated areas. Lack of signal for
more organized heavy rain should preclude a Slight Risk upgrade.

Across the Midwest, specifically Iowa, an overnight Saturday night
MCS is expected to impact much of Iowa and small portions of the
neighboring states. While guidance has come into better agreement
on the areas likely to be affected, there remains a broad variety
of solutions as to how much rain will fall across much of central
and eastern Iowa. Thus, for now the area remains in a Marginal, but
will continue to be monitored for a Slight risk upgrade with future
updates.

Signals for heavy rain across much of the Eastern Seaboard remain
very diffuse again on Saturday. Similar to Friday, there remains
plentiful moisture all up and down the Atlantic coast. Somewhat
better forcing from a negatively tilted trough north of the Great
Lakes should allow for more widespread storms, but they will remain
quite progressive. Further south, there will be more moisture, but
a lack of forcing. Most of the heaviest rains look to be from north
Florida through coastal South Carolina.

Wegman


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