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: 2026-05-07
 Forecast Period: May 7 to September 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 10.50 213 2026-05-07
90 % 10.50 214 2026-05-14
70 % 10.88 339 2026-05-28
50 % 11.28 503 2026-06-08
30 % 11.92 838 2026-06-14
10 % 12.47 1200 2026-07-14
05 % 12.74 1404 2026-08-05

Peakflow exceedence plot for PILW1

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