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FGUS76 KSEW 152205
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WAC009-027-029-031-033-035-041-045-053-055-057-061-067-073-161800-

Hydrologic Outlook
National Weather Service Seattle WA
305 PM PDT Fri Aug 15 2025

...THREAT OF IMPACTS FROM HEAVY RAINFALL LATE TONIGHT THROUGH
SATURDAY FOR MOST OF WESTERN WASHINGTON...

A frontal system will move across the area Friday into Saturday
across western Washington. Through Saturday afternoon, 3-5 inches of
rain are expected across the mountains, with 0.5-1.5 inches expected
through the lowlands.

Very dry antecedent conditions has left the area soils dry and hard.
This amount of rainfall in one storm will not have much time to soak
into the very dry soil, which will result in heavy surface runoff.
Impacts are uncertain due to how much moisture will be able to be
absorbed by the soil. Several different threats are expected with
this storm, which are detailed below.

*Urban and urban-like flooding will be possible in flat areas and
roadways.

*Some small streams and creeks may become swollen due to rapid
runoff while others may remain lower if the channel bed is able to
absorb the water efficiently.

*Rivers will not flood, but will undergo rapid rises to unusually
high levels for this time of year, some of which may reach daily
record crests. This will pose a threat to those engaged in
recreational activities in and along river channels.

*Burn scars will have the potential to undergo impacts, but the
probability is low. Impacts may include flash flooding, debris
flows, rock falls, and other falling debris.

*Those engaging in recreational activities in the mountains may face
challenges to where high water may make forest roads and trails
difficult to traverse.

Please monitor the latest forecasts from the National Weather
Service for additional information.
$$

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