Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1152 AM EDT Mon Apr 27 2026
Day 2
Valid 12Z Tue Apr 28 2026 - 12Z Wed Apr 29 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE ARKLATEX
INTO THE MID SOUTH...

A favorable environment will exist for numerous organized
thunderstorms over the southern U.S. on Tuesday, with a broad warm
sector containing very strong instability (CAPE over 3000 j/kg),
deep moisture (PW climbing into the 1.6 to 2.0 inch range), and
strong deep layer shear (0-6km bulk shear 40-60 knots). In that
sort of environment, rain rates should reach 2 inches per hour. The
open question is what sort of mesoscale boundaries may exist to
focus convective development, and whether or not some of these will
be oriented in a west-east fashion (parallel to the bulk shear
vectors). Any prominent boundaries that are favorably oriented
could easily focus a corridor of significant rainfall and flash
flooding in this sort of environment. However, an equally plausible
scenario would be more scattered clusters and lines of
thunderstorms that can produce localized heavy rainfall and flash
flooding, but fail to focus the convection in a way that leads to
more significant totals. For now, it seems reasonable to maintain
the broad Slight Risk and wait for greater confidence in the
mesoscale details.

Lamers

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