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STILLAGUAMISH--NEAR ARLINGTON
   State:  Washington    County:  SNOHOMISH
   Latitude:  48 12' 13" North    Longitude:  122 7' 41" West
   Elevation:  65 feet
   Supporting WFO:  Seattle    
   Action Stage:  12.5'   Flood Stage:  14'   Moderate Flood Stage:  17.5'
   Major Flood Stage:  19'

Forecasts are calculated from a forecast time series that approximates flow at a 6 hour time step interval. Observed instantaneous peaks can be higher than model forecast peaks.

STILLAGUAMISH--NEAR ARLINGTON   (ARLW1)
Forecasts for Water Year 2026
Ensemble Date: 2026-08-16
 Forecast Period: August 16 to December 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 5.20 6888 2026-10-09
90 % 6.39 10104 2026-10-19
70 % 9.28 18780 2026-11-04
50 % 12.23 28687 2026-11-12
30 % 13.40 32911 2026-11-18
10 % 17.50 48490 2026-11-26
05 % 21.75 66007 2026-11-29

Peakflow exceedence plot for ARLW1

 Click to download runoff traces used in forecast.  Click for comma delimited data used in plot.csv icon