Peakflow Forecasts Header

S YAMHILL--NEAR WILLAMINA
   State:  Oregon    County:  POLK
   Latitude:  45 2' 49" North    Longitude:  123 30' 10" West
   Elevation:  236 feet
   Supporting WFO:  Portland    

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.

S YAMHILL--NEAR WILLAMINA   (WLAO3)
Forecasts for Water Year
2026
Ensemble Date: 2026-02-06
Forecast Period: February 6 to June 1
Exceedence
Probability
Stage
feet
Discharge
CFS
Probable
Date of Peak
95 % 4.74 1274 2026-02-12
90 % 5.00 1601 2026-02-19
70 % 6.00 2353 2026-02-26
50 % 6.00 3127 2026-03-11
30 % 8.00 4943 2026-03-20
10 % 11.00 8182 2026-04-03
05 % 11.00 9293 2026-04-08

Peakflow exceedence plot for WLAO3

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