Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
759 PM EST Tue Nov 10 2026

Day 1
Valid 01Z Wed Nov 11 2026 - 12Z Wed Nov 11 2026

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

Pereira


Day 2
Valid 12Z Wed Nov 11 2026 - 12Z Thu Nov 12 2026

...2030Z Update...

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

Wegman


Day 3
Valid 12Z Thu Nov 12 2026 - 12Z Fri Nov 13 2026

...2030Z Update...

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

Wegman


Day 4 and Day 5

Valid 12Z Fri Nov 13 2026 - 12Z Sun Nov 15 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF CENTRAL AND SOUTH TEXAS AS WELL AS THE OLYMPIC PENINSULA OF
WASHINGTON ON SATURDAY- SATURDAY NIGHT...

...2030Z Update...

The probability of rainfall exceeding flash flood guidance is less
than 5 percent on Day 4 (12Z Fri-12Z Sat).

...South Texas...

A plume of moisture riding a low level jet straight out of the
Caribbean will extend into portions of South Texas on Saturday.
This plume of moisture will be uplifted by an approaching upper
level shortwave, allowing for more widespread shower and
thunderstorm development across this region. The shortwave will be
quite fast-moving, going from the Rio Grande to Mississippi/Alabama
in 24 hours. Thus, the window where the heaviest rains will fall
will be relatively short. Once the shortwave goes by, the relative
lack of forcing should diminish the coverage and intensity of
convection across the region. Soils over all of South Texas are
near saturation from recent rains. Between now and Saturday,
however, much of that time will be dry, allowing for significant
draining of the soils. Thus, by the time of this event, at least
some of the rainfall should soak into the ground before any
flooding threat emerges. The inherited Marginal was largely
maintained as there is good continuity among the guidance as to
where the heaviest rains will set up...from roughly Victoria, TX to
the southern Hill Country northwest of San Antonio. With less
certainty as to the northeastern extent, the portion of the Houston
Metro in the previous Marginal risk was removed with this update.

...Western Washington...

A new Marginal Risk was added in coordination with SEW/Seattle, WA
forecast office with this update. Much of the Olympic Peninsula
will see 5 consecutive days of rain between now and Saturday. Thus,
by Saturday, soils across this region will be well-saturated.
Maximum rainfall amounts on the windward side of the Olympics will
exceed 2 inches for the day, which when added to the prior days'
rainfall could result in isolated instances of flash flooding from
the coast to the crest of the Olympics. Considering how well this
area handles large amounts of rain, this remains a low-end Marginal
Risk threat, that may be removed if forecast rainfall amounts
decrease.

Wegman


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