Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
306 AM EST Wed Nov 11 2026

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

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

Kleebauer


Day 2
Valid 12Z Thu Nov 12 2026 - 12Z Fri Nov 13 2026

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

Kleebauer


Day 3
Valid 12Z Fri Nov 13 2026 - 12Z Sat Nov 14 2026

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

Kleebauer


Day 4 and Day 5

Valid 12Z Sat Nov 14 2026 - 12Z Mon Nov 16 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF TEXAS AND THE WESTERN GULF COAST AS WELL AS THE OLYMPIC
PENINSULA OF WASHINGTON...

...Southern/eastern Texas and western Gulf Coast...

Strong high pressure over the eastern U.S. and an approaching
southern stream upper-wave will help to lift a lingering frontal
boundary back northward over portions of southern Texas and the
western Gulf Coast day 4/Saturday and day 5/Sunday. This will allow
for southeasterly moist Gulf return flow and set the stage for a
renewed round of thunderstorms with the potential for locally heavy
downpours. One complicating factor will be the timing and track of
the initial southern stream upper-wave day 4 as well as a complex
split-flow pattern upstream, with additional energy likely to
translate eastward into the day 5 timeframe. This leads to
significant differences in the latest global guidance, with highly
variable QPF coverage/amounts both day 4 and day 5. However, when
taken as a whole, the guidance does agree on the potential for
heavy totals into the 2-4" range with locally higher amounts
possible each day. For now, have opted to make only modest changes
to the Marginal on day 4 (an eastward extension from south-
central/southern Texas along the western Gulf Coast) as well as
introduce a broad Marginal on day 5 a bit further east across
portions of eastern Texas and the western Gulf Coast into western
Louisiana given the uncertainty. These areas roughly cover where
the heavier QPF amounts tend to cluster in those pieces of guidance
that show heavier amounts for each day, respectively. Further
areal adjustments are likely with subsequent forecast updates and a
categorical upgrade may ultimately be needed once there is greater
confidence in the location of heaviest rainfall.

...Western Washington...

A second weak Atmospheric River is expected to impact western
portions of Washington in the day 4/Saturday time frame. Wet
antecedent conditions will be in place following an initial
Atmospheric River mid- to late week, with the additional rainfall
possibly leading to isolated flooding, particularly from the coast
to the windward side of the Olympics. The latest guidance generally
agrees on totals in the 1-3" range which are on the lighter side
impact- wise for the region, and amounts with the initial
Atmospheric River have trended downward a bit as well, so the risk
may ultimately not materialize if current trends continue.

Putnam


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