Peakflow Forecasts Header

CHEHALIS--AT PORTER
   State:  Washington    County:  GRAYS HARBOR
   Latitude:  46 56' 21" North    Longitude:  123 18' 50" West
   Elevation:  24 feet
   Supporting WFO:  Seattle    
   Action Stage:  45.5'   Flood Stage:  48'   Moderate Flood Stage:  50'
   Major Flood Stage:  52'

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.

CHEHALIS--AT PORTER   (CRPW1)
Forecasts for Water Year 2026
Ensemble Date: 2026-09-10
 Forecast Period: September 10 to January 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 39.69 7900 2026-11-13
90 % 41.07 9408 2026-11-23
70 % 45.84 16200 2026-11-30
50 % 47.12 19482 2026-12-10
30 % 48.34 24809 2026-12-17
10 % 49.69 34481 2026-12-29
05 % 50.02 37609 2026-12-31

Peakflow exceedence plot for CRPW1

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