Peakflow Forecasts Header

GRANDE RONDE--NEAR PERRY
   State:  Oregon    County:  UNION
   Latitude:  45 21' 15" North    Longitude:  118 11' 29" West
   Elevation:  2950 feet    Gage Datum:  
   Supporting WFO:  Pendleton    
   Action Stage:  5.8'   Flood Stage:  6.6'   Moderate Flood Stage:  7.5'

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.

GRANDE RONDE--NEAR PERRY   (LGNO3)
Forecasts for Water Year 2026
Ensemble Date: 2025-11-16
 Forecast Period: November 16 to March 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 1.22 70 2025-11-27
90 % 1.52 134 2026-01-10
70 % 2.01 290 2026-02-02
50 % 2.52 525 2026-02-15
30 % 2.82 708 2026-02-22
10 % 4.10 1866 2026-03-01
05 % 4.66 2558 2026-03-01

Peakflow exceedence plot for LGNO3

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