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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: 2026-04-15
 Forecast Period: April 15 to August 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 5.69 8156 2026-04-15
90 % 5.69 8156 2026-04-15
70 % 5.69 8156 2026-04-15
50 % 6.13 9359 2026-05-08
30 % 6.73 11064 2026-05-28
10 % 8.25 15555 2026-06-22
05 % 9.02 17936 2026-07-12

Peakflow exceedence plot for ARLW1

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