Peakflow Forecasts Header

OKANOGAN--NEAR TONASKET
   State:  Washington    County:  OKANOGAN
   Latitude:  48 37' 57" North    Longitude:  119 27' 28" West
   Elevation:  861 feet
   Supporting WFO:  Spokane    
   Action Stage:  14'   Flood Stage:  15'   Moderate Flood Stage:  17'
   Major Flood Stage:  18'

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.

OKANOGAN--NEAR TONASKET   (TONW1)
Forecasts for Water Year 2026
Ensemble Date: 2026-07-10
 Forecast Period: July 10 to November 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 4.79 986 2026-07-10
90 % 4.79 986 2026-07-10
70 % 4.79 986 2026-07-10
50 % 4.79 986 2026-07-10
30 % 5.55 1576 2026-10-17
10 % 6.92 2993 2026-10-31
05 % 8.34 4900 2026-11-01

Peakflow exceedence plot for TONW1

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