Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
737 PM EST Mon Nov 24 2025
Day 1
Valid 01Z Tue Nov 25 2025 - 12Z Tue Nov 25 2025

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE LOWER MISSISSIPPI VALLEY INTO NORTHEAST TEXAS...

...01Z Update...

The primary changes to the ERO risk areas this evening were to trim
the west and northwestern portions of the risk areas in Texas and
Arkansas, as the steadiest, heaviest rains have ended in the
trimmed areas. Elsewhere, the ERO remains unchanged. A slow moving
front is drawing sufficient Gulf moisture northeastward from
eastern Texas into portions of the southern Tennessee Valley. Along
this corridor of moisture, prodigious lightning producing storms
are also peaking in intensity with rainfall rates topping 2 inches
per hour. In the areas where this heavy rain is falling, flash
flooding has been occurring. Fortunately storms reaching an
intensity capable of this intensity of rainfall have been quite
isolated among the larger complex of storms. The Slight Risk area
continues to highlight the area where enough rainfall has been
falling that should a storm move over those areas with heavier
rainfall rates, then resultant flash flooding is likely.

Slow moving storms associated with the southern end of the line
will likely impact the Houston metro later tonight. Much of the
CAMs guidance have suggested that by then the storms will be in a
progressive line, limiting the amount of time heavy rain is
occurring over the flood-sensitive metro.
On the other end of the Slight, storms with embedded moderate to
briefly heavy rainfall are also moving into northern Mississippi.
Guidance suggests moderate rain will continue over this area for
much of the night. This too could result in widely scattered
instances of flash flooding. Since by late tonight instability will
be waning, most of Mississippi other than the northwestern-most
counties remain in a Marginal Risk. Thus, it should be noted that
both these areas are in the higher end of the Marginal Risk threat.

Wegman

...Previous Discussion...

The overall forecast philosophy remains on track for this update.
Areas of showers and thunderstorms are expected to redevelop from
southwest to northeast within an 850mb low-level jet axis extending
from near Austin, TX through the ArkLaTex. Some of the convection
will interact with left over low-level boundaries from this
morning's convection, further enhancing rainfall potential and
resulting in localized 2-4 inch daily totals. The greatest risk of
these enhanced rainfall totals will focus around northeast Texas
into northwest Louisiana and vicinity.

The overall convective scenario should translate eastward toward
the Lower Mississippi Valley through the overnight hours and become
increasingly displaced from surface-based buoyancy focused across
southeast Texas/southwest Louisiana. Flash flooding should remain
possible, but gradually decrease in coverage with eastward extent.

Risk areas across Oklahoma, northern/central Arkansas, and parts of
west-central Texas were trimmed as ongoing convective trends
suggest that any remaining flash flood threat has lessened for the
remainder of the forecast period.

Cook


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