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 2027
Ensemble Date: 2026-10-05
 Forecast Period: October 5 to February 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 3.99 179 2026-11-20
90 % 5.14 303 2026-11-26
70 % 7.64 648 2026-12-09
50 % 9.92 1041 2026-12-26
30 % 11.40 1336 2027-01-10
10 % 13.34 1869 2027-01-23
05 % 14.28 2248 2027-01-30

Peakflow exceedence plot for SYCO3

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