Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
405 AM EDT Fri Apr 18 2025
Day 1
Valid 12Z Fri Apr 18 2025 - 12Z Sat Apr 19 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR NORTHEASTERN
OKLAHOMA THROUGH CENTRAL MISSOURI...

A persistent southerly low-level jet transporting deep tropical
moisture into the Texas Gulf Coast and along a very slow moving
frontal zone draped across the Plains to the upper Great Lakes will
lead to the development of convection during peak heating. However,
the strongest of the storms will likely be during the late evening
and overnight hours. The strong cold front to the north will run
into opposing flow from the LLJ, causing its progression south and
east to slow as it approaches Oklahoma and Missouri from the
northwest. This will act as a wall, resulting in the LLJ air mass
to ride up and into the front, then track along the frontal
interface to the northeast. This setup will be favorable for
training of thunderstorms and some of the individual cells may
advance quickly to the northeast as the low-level jet intensifies
to 50 kt over northwestern Arkansas Friday night.

The rain will be somewhat offset from the area of greatest
historic rainfall from 2 weeks ago, and the smaller streams and
creeks have fully drained from that event, but the bigger rivers,
including the Missouri, Arkansas, and Mississippi continue to
drain, and this new influx of rainfall could back up as the new
rainfall meets already full rivers. The bulk of the event will
focus into the Day 2 period. With greater instability available
for the storms to produce heavy rainfall during this period, it's
likely that where the storms are most persistent, there will be
widely scattered instances of flash flooding, especially near the
Tulsa and Joplin metros. A Marginal Risk area spans from the
vicinity of the Oklahoma/Texas border northeastward to
Illinois/Indiana. The Slight Risk was adjusted a small amount to
the west than the previous forecast.

Campbell

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