Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
237 AM EDT Mon Apr 22 2024

Day 1
Valid 12Z Mon Apr 22 2024 - 12Z Tue Apr 23 2024

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Roth


Day 2
Valid 12Z Tue Apr 23 2024 - 12Z Wed Apr 24 2024

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Roth


Day 3
Valid 12Z Wed Apr 24 2024 - 12Z Thu Apr 25 2024

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

...In and near OK...
The combination of return flow from the Gulf of Mexico and
convergence along an incoming front should be able to spark showers
and thunderstorms as it marches southward. Temperatures at 700 hPa
strongly imply an uncapped atmosphere. Diffluent 1000-500 hPa
thickness exists here, implying that thunderstorm complexes would
be theoretically possible. CAPE is expected to build to 1000-2000
J/kg. Precipitable water values rise into the 1.25-1.5" range.
Currently, the guidance still shows a bit of spread in position,
which in the southern Plains is problematic as areas north of
southern OK need quite a bit of rainfall to reach flash flood
guidance values due to recent dryness, while areas closer to the
OK/TX border do not due to recent heavy rainfall. The overlap that
exists is across east- central OK, which was spared from the recent
heavy rainfall. Only the 00z ECMWF has enough rainfall to imply a
flash flood threat at the moment. The uncertainty in placement and
amounts keeps the risk of excessive rainfall under 5 percent. But,
if the guidance trends southward and wetter, which is quite
possible based on the expected uncapped atmosphere and placement of
the diffluent thickness in the 00z GFS guidance, a risk area could
prove useful down the road. Stay tuned.

Roth


Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt