Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
417 PM EDT Wed Apr 30 2025
Day 3
Valid 12Z Fri May 02 2025 - 12Z Sat May 03 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS FROM THE
SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY...

A flash flood event may be ongoing at the beginning of the period,
with convection developing on Thursday Night in southern Oklahoma
and continuing into Friday morning. This may continue beyond 12Z
Friday (into this Day 3 period) in SE OK and AR in the region of
strong upper-level divergence. The existing Slight Risk over TX was
expanded northward to account for this scenario. Whether that round
of convection wanes due to more extensive cloud cover and limited
daytime heating, or progresses southeast and becomes reinvigorated
during the afternoon, the threat of heavy rainfall and flash
flooding should expand southeast on Friday into the Lower
Mississippi Valley (S AR, N LA, W MS) and much of C and E TX. This
would be via progression of the early round of storms, or
redevelopment in the afternoon and evening hours.

Strong instability will remain over much of the warm sector with
CAPE values potentially in excess of 3000 j/kg in some areas, and
PW values are expected to increase above 1.5 inches as SSE flow
increases off the Gulf. The combination of strong instability and
high PWs will favor very heavy rain rates in organized convection,
and this is supportive of the broad Slight Risk on the new
outlook. At the moment, model guidance is showing the most
consistent signal for heavy rain from Texas Hill Country in C TX
east- northeast into the Piney Woods region of E TX. Given the
overall environment, it is possible an upgrade to a Moderate Risk
may be needed at some point.

Lamers

Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt