116
AGUS74 KWCO 311506
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1006 AM CDT FRI OCT 31 2025

.Synopsis...
Isolated flooding impacts possible for the Pacific Northwest through
Saturday... Prolonged heavy rainfall event upcoming for the Mariana
Islands...

.Pacific Northwest...
Periods of moderate rainfall are expected through Saturday (day 2) across
western WA. This could lead to isolated urban and small stream flooding
impacts, in addition to isolated minor mainstem river flooding on rivers
draining the Olympics and western slopes of the Cascades in WA (NWRFC,
HEFS). Peak flows on most rivers are expected Saturday (day 2). Top layer
(0 - 10 cm) soils are moist (NASA SPoRT) and streamflows are running normal
to above normal (USGS) both in response to recent rainfall across the
region, increasing confidence in sufficient runoff for isolated nuisance
flooding impacts. A brief period of dry weather is expected across the
region ahead of the next surge of moisture across WA, OR, and northern CA
mid next week, which could bring a renewed flooding threat to the region,
but details are highly uncertain.

.Mariana Islands...
A prolonged heavy rainfall event is possible late this weekend into next
week for Guam, Rota, Tinian, and Saipan. Rainfall totals could exceed 3 -
7", which is expected to produce minor flooding impacts across the islands,
with flash flooding possible across Guam.

Additional National Water Center products are available at
www.weather.gov/owp/operations

This product will begin to be issued twice daily, with new issuance times,
beginning approximately 3 November 2025. The routine primary issuance time
of the product will be at 20 UTC, with routine daily updates to the
discussion being completed around 7 AM Central Time.

//JEC

$$