Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1001 AM EST Sat Dec 13 2025
Day 2
Valid 12Z Sun Dec 14 2025 - 12Z Mon Dec 15 2025

..THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
WESTERN WASHINGTON STATE LATE SUNDAY NIGHT/EARLY MONDAY MORNING...

Maintained the Marginal Risk area over parts of the Olympic and
northern Cascade Ranges in Washington as the next push of moisture
approaches late Sunday night into the early morning hours of
Monday. The models have shown some run to run differences with QPF
but no real clear trend. One consistent signal is that the
orientation of the moisture plume remained more southwest-northeast
than the event that just ended a couple of days ago. That still
points to the idea that rainfall may not increase in coverage or
intensity until late in the Day 2 period. Based on the expected IVT
plume increasing to over 600 at about the time that the flow
reaches the coast and begins to take on more of an on- shore
component...am inclined to follow the ensemble idea of 0.75 inches
to locally 1.5 inches of precipitation focused in the terrain. The
area is sensitive given the nearly week-long excessive rainfall
event...so any additional rainfall is expected to bring renewed
hydrologic concerns. Given a fairly tight window of opportunity for
rainfall during the outlook period...and at least some questions
about timing of the onset....still think a Marginal Risk is
sufficient for now although later shifts can adjust if needed.

Bann

Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt