Peakflow Forecasts Header

WALLA WALLA--NEAR TOUCHET
   State:  Washington    County:  WALLA WALLA
   Latitude:  46 2' 0" North    Longitude:  118 44' 0" West
   Elevation:  405 feet
   Supporting WFO:  Pendleton    
   Action Stage:  10'   Flood Stage:  13'   Moderate Flood Stage:  15'
   Major Flood Stage:  17'

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.

WALLA WALLA--NEAR TOUCHET   (TCHW1)
Forecasts for Water Year 2026
Ensemble Date: 2026-08-16
 Forecast Period: August 16 to December 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 3.15 102 2026-11-01
90 % 3.86 244 2026-11-03
70 % 5.01 642 2026-11-12
50 % 5.41 840 2026-11-21
30 % 6.41 1396 2026-11-25
10 % 8.06 2384 2026-11-28
05 % 8.38 2606 2026-11-30

Peakflow exceedence plot for TCHW1

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