Peakflow Forecasts Header

WILLAPA--NEAR WILLAPA
   State:  Washington    County:  PACIFIC
   Latitude:  46 39' 3" North    Longitude:  123 39' 7" West
   Elevation:  4 feet
   Supporting WFO:  Portland    
   Action Stage:  20'   Flood Stage:  21'   Moderate Flood Stage:  22'
   Major Flood Stage:  24'

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.

WILLAPA--NEAR WILLAPA   (WILW1)
Forecasts for Water Year 2027
Ensemble Date: 2026-10-10
 Forecast Period: October 10 to February 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 8.57 1974 2026-11-20
90 % 11.44 3481 2026-11-23
70 % 15.14 5814 2026-12-07
50 % 17.34 7484 2026-12-20
30 % 20.48 11226 2027-01-06
10 % 23.15 15074 2027-01-24
05 % 23.60 17150 2027-01-29

Peakflow exceedence plot for WILW1

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