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 2025
Ensemble Date: 2025-06-30
 Forecast Period: June 30 to October 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 0.97 31 2025-07-16
90 % 0.99 34 2025-07-24
70 % 1.10 48 2025-08-21
50 % 1.21 62 2025-09-10
30 % 1.28 74 2025-09-22
10 % 1.58 142 2025-09-30
05 % 2.00 278 2025-10-01

Peakflow exceedence plot for LGNO3

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