Peakflow Forecasts Header

PILCHUCK--NEAR SNOHOMISH
   State:  Washington    County:  SNOHOMISH
   Latitude:  47 56' 6" North    Longitude:  122 4' 18" West
   Elevation:  0 feet
   Supporting WFO:  Seattle    
   Action Stage:  16'   Flood Stage:  18'   Moderate Flood Stage:  20'
   Major Flood Stage:  22'

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.

PILCHUCK--NEAR SNOHOMISH   (PILW1)
Forecasts for Water Year 2026
Ensemble Date: 2026-09-10
 Forecast Period: September 10 to January 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 12.75 1379 2026-10-30
90 % 13.10 1627 2026-11-12
70 % 13.84 2243 2026-11-25
50 % 14.47 2830 2026-12-10
30 % 15.38 3753 2026-12-15
10 % 16.08 4505 2026-12-26
05 % 17.52 6207 2026-12-30

Peakflow exceedence plot for PILW1

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