Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
315 AM EST Fri Nov 13 2026

Day 1
Valid 12Z Fri Nov 13 2026 - 12Z Sat Nov 14 2026

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

Bann


Day 2
Valid 12Z Sat Nov 14 2026 - 12Z Sun Nov 15 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS NORTHWEST
WASHINGTON STATE IN THE AREA OF THE OLYMPIC PENINSULA...

00Z guidance continues to show the arrival of another round of
moderate to heavy rainfall across portions of northwest Washington
and the Olympic peninsla on Saturday. The two-day rainfall total ay
be enough to result in isolated flash- and areal-flooding. Rainfall
forecasts of an additional 1 inch to 3 inches, with locally
higher amounts, are expected through Saturday night or early Sunday
morning. Much of the rainfall is expected to occur in a 12-hr
window before the passage of a cold front late in the forecast
period.  This could send some of the river banks overflowing and
cause some local flood concerns, some of which could be flashy.
Still felt there was no fundamental changes needed with the latest
forecast.

Bann


Day 3
Valid 12Z Sun Nov 15 2026 - 12Z Mon Nov 16 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF EASTERN TEXAS AND WESTERN LOUISIANA SUNDAY...

Only minor adjustments to the Marginal Risk over eastern Texas and
western Louisiana were made this outlook cycle given continued
model signals for potentially excessive rainfall near the Gulf
coast. There was little resolution to the question whether the
heaviest rainfall stays off-shore or if makes its way inland. Consensus
of the preferred guidance still indicates the heaviest amounts are
likely to center near the upper Texas/southwestern Louisiana
coasts, Some models are showing amounts that would warrant an
upgrade along the coast as northern stream energy overtakes a
leading southern stream wave. That would provide providing the
necessary lift to support scattered convection. However, with
limited instability would likely temper rates to the north. However,
due to uncertainty regarding whether the heaviest rainfall will
develop offshore, held off from upgrading to a Slight Risk once
again.

Bann


Day 4 and Day 5

Valid 12Z Mon Nov 16 2026 - 12Z Wed Nov 18 2026

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

An upper-wave will continue eastward along the Gulf Coast Day
4/Monday. Strengthening high pressure to the north as well as
northerly flow in wake of the wave should help to drive a frontal
boundary across Texas southeastward into the Gulf. This should keep
greater moisture/instability and the focus for storms mostly
offshore compared to Sunday. Even if the boundary/storms were to
set up a bit further north along the coast, FFGs are high and would
require a much greater signal for widespread coverage/several inch
rainfall totals to raise a concern for flash flooding.

To the west, an upper-trough and accompanying cold front will
progress eastward from the West Coast into the Interior West
Monday-Tuesday. Increasing moisture along and with the frontal
passage will lead to scattered thunderstorms across the Desert
Southwest. However, limited instability should keep rates low and
the progressive nature of the system passage should limit rain
totals overall.

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