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NF STILLAGUAMISH--NEAR ARLINGTON
   State:  Washington    County:  SNOHOMISH
   Latitude:  48 15' 38" North    Longitude:  122 2' 51" West
   Elevation:  89 feet
   Supporting WFO:  Seattle    
   Action Stage:  10.7'   Flood Stage:  13'   Moderate Flood Stage:  14'
   Major Flood Stage:  15'

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.

NF STILLAGUAMISH--NEAR ARLINGTON   (ARGW1)
Forecasts for Water Year 2026
Ensemble Date: 2026-06-05
 Forecast Period: June 5 to October 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 2.77 777 2026-06-10
90 % 2.77 777 2026-06-10
70 % 3.32 1303 2026-07-12
50 % 3.81 1938 2026-08-26
30 % 4.21 2598 2026-09-21
10 % 6.20 6643 2026-09-29
05 % 6.94 7995 2026-10-01

Peakflow exceedence plot for ARGW1

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