590
AGUS74 KWCO 011500
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT SAT NOV 1 2025

.Synopsis...
Isolated flooding impacts possible for the Pacific Northwest and Northern
California... Flooding impacts possible for American Samoa and the Mariana
Islands... Localized flooding possible in Puerto Rico...

.Pacific Northwest and Northern California...
Moderate rainfall will persist through today across portions of western WA
and may bring isolated urban and small stream flooding impacts. Isolated
river flooding is also forecast across portions of western WA, particularly
on rivers draining the Olympics and western slopes of the Cascades in WA.
Topsoils are wet across the region (NASA SPoRT) and streamflows are running
above normal (USGS) in response to recent rainfall, increasing confidence
for isolated flooding impacts.

A brief period of dry weather is forecast for Sunday and Monday (days 2 and
3), before the next surge of moisture brings additional precipitation to
the Pacific Northwest and into Northern California starting on Tuesday (day
4). Flooding concerns will return across portions of the area in response
to the return in precipitation, with urban and small stream flooding
possible during mid-to-late week.

.American Samoa...
Flash flooding and landslides are possible through Sunday as a nearby
trough brings periods of showers and thunderstorms to the islands.

.Mariana Islands...
Invest 99W is expected to bring heavy rainfall to the islands starting
Sunday night through at least Thursday night. Rainfall amounts of 3 - 7"
are expected to produce minor flooding across the islands, with flash
flooding possible in Guam.

.Puerto Rico...
Periods of showers and thunderstorms may elicit localized flooding impacts
through the rest of today across the island as a tropical wave moves across
the region.

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.

//JAW

$$