Peakflow Forecasts Header

COWLITZ--AT PACKWOOD
   State:  Washington    County:  LEWIS
   Latitude:  46 37' 0" North    Longitude:  121 40' 59" West
   Elevation:  1048 feet
   Supporting WFO:  Seattle    
   Action Stage:  8.2'   Flood Stage:  10.5'   Moderate Flood Stage:  11'
   Major Flood Stage:  12'

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.

COWLITZ--AT PACKWOOD   (PACW1)
Forecasts for Water Year 2026
Ensemble Date: 2026-05-13
 Forecast Period: May 13 to September 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 3.23 3203 2026-05-14
90 % 3.23 3203 2026-05-14
70 % 3.23 3203 2026-05-14
50 % 3.23 3203 2026-05-14
30 % 3.23 3203 2026-05-14
10 % 3.98 4573 2026-06-04
05 % 4.59 5852 2026-06-08

Peakflow exceedence plot for PACW1

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