Peakflow Forecasts Header

JOHNSON CREEK--AT SYCAMORE
   State:  Oregon    County:  MULTNOMAH
   Latitude:  45 28' 40" North    Longitude:  122 30' 24" West
   Elevation:  228 feet
   Supporting WFO:  Portland    
   Action Stage:  10'   Flood Stage:  11'   Moderate Flood Stage:  13'
   Major Flood Stage:  14'

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.

JOHNSON CREEK--AT SYCAMORE   (SYCO3)
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 % 4.41 222 2026-02-09
90 % 4.41 222 2026-02-09
70 % 5.02 289 2026-02-20
50 % 6.34 456 2026-03-02
30 % 7.59 640 2026-03-17
10 % 9.39 942 2026-04-08
05 % 11.39 1334 2026-04-19

Peakflow exceedence plot for SYCO3

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