Forecast Accuracy

I’ve been tracking accuracy of my forecasts for a few years but have never actually posted it online.  After getting tired of the “you guys are ALWAYS wrong” calls and emails, I figured it’s time to post the stats online:

The criteria:  I track low/high forecast temp for PDX (Portland International Airport), a central location in the metro area.  I track just my forecasts which are generally Monday-Friday.  The forecast must be within 3 degrees of the actual temp for the following calendar day.  For rainfall it’s a bit more straightforward;  if rain is forecast and it is too little to get measured at PDX I’m wrong.  Same with a no rain forecast and rain actually arrives.  In the comments section I give my thoughts and grade myself down if the numbers down seem to represent reality.  For example:  I say it’s going to rain tomorrow by late morning.  Then let’s say the rain doesn’t arrive until 11pm, leaving the day “rainy” in the climate stats, but to any normal person it didn’t REALLY rain.  Got to mark myself down some for that.  Or there is no category for “major screwups” (2-7″ unexpected snowfall 12/2009), which don’t really fall into rain/clouds or temp columns.

Chief Meteorologist Mark Nelsen









11 Responses to Forecast Accuracy

  1. Evelyn Fuller says:

    Hey y’all, on ur weather broadcast last week and today u have wrong info Damascus is in Gresham’s place on the map. Pleadease fix it. Thank you!

  2. sajtsajt says:

    Your percentages are great, because weather predictions more then 2 days are with low accuracy.

  3. William T. Matthews says:

    There was a snow storm on March 15 2002 with hugh snow flakes
    in Columbia county, we know this as a fact because this was our first date almost 10 years ago. There was a motor vehicle accident that night 2 miles south of Rainier, Oregon due to snow.

  4. gidrons says:

    Do you track accuracy 3 days out?

  5. I am totally delighted with your weather predictions!!! .This gal has been tracking seismic activity and a quake is forecasted for the 10th by the geological service and she agrees and shows why. I thought it deserved a look!!! Please look at the video? Tx, Della

  6. bobby says:

    how long is it going to rain today???

  7. bobby says:

    great call on the no rain we are receiving right now missed that one genius!

  8. Timmy_Supercell (Hillsboro) says:

    Nice one! I agree with the percentages so far…

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