Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
228 AM EST Sun Nov 2 2025

Day 1
Valid 12Z Sun Nov 02 2025 - 12Z Mon Nov 03 2025

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

Churchill

Day 2
Valid 12Z Mon Nov 03 2025 - 12Z Tue Nov 04 2025

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

Churchill


Day 3
Valid 12Z Tue Nov 04 2025 - 12Z Wed Nov 05 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHWESTERN CALIFORNIA AND FAR SOUTHWESTERN OREGON...

The next strong landfalling atmospheric river (IVT > 750 kg/ms)
looks to impact coastal portions of northern CA/far southwestern OR
come Tuesday afternoon, likely peaking in strength in the evening
to overnight period. Initial low-level flow earlier in the day
looks more ideally directed perpendicular to the coast/mountains,
but by the time higher IVT sets in veering to the SW-SSW may
mitigate the effectiveness of the topographic lift (with otherwise
limited instability as MUCAPE of less than 250 J/kg is forecast).
Even still, this is a relatively warm system (with the cold core
staying offshore until beyond Day 3) and PWATs of 1.2-1.4" are in
the vicinity of the 90th percentile climatologically. Rainfall
totals of 2-4" are generally expected (and may locally exceed 4"),
and much of that could occur in a 6-12 hour period. The inherited
Marginal Risk is sufficient (in-line with the latest GEFS-driven
machine learning first guess field) and has been maintained (with
only minor adjustments based on the latest models QPF footprint).
Any flash flood impacts are most likely where relatively high
rainfall rates (0.25"+/hr) coincide with sensitive burn scars.

Churchill


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