Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
415 AM EDT Sat Apr 27 2024
Day 3
Valid 12Z Mon Apr 29 2024 - 12Z Tue Apr 30 2024

...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS ACROSS PORTIONS OF
THE LOWER MISSISSIPPI VALLEY...

The convective and heavy rain threat shifts eastward into the lower
MS Valley on Monday. Still seeing an impressive combination of
mid/upper forcing, low level convergence, instability and moisture
to support a flash flood risk. At this time these ingredients look
a bit more progressive than previous days, which should result in
quicker cell motions and an overall lowered flash flood threat.
Nonetheless, rainfall rates should still be quite high given the
instability and moisture in place, so 2"+/hr remains probable in
spots. This should be enough to drive an isolated to scattered
flash flood risk, especially over urban areas.

Models are in pretty good agreement on the axis of heaviest
rainfall, generally trending a bit further east compared to
previous runs. The greater uncertainty lies with where to place
the northern end of the Slight risk. The ECMWF remains further
north than the GFS, GEM reg and UKMET. For now will keep the
northern edge of this Slight risk over western TN, as this better
aligns with the model consensus, with even the machine learning EC
AIFS further south than the deterministic ECMWF.

Chenard