Good Afternoon,
The NWRFC updated its 120 day forecast (STP) at 12:58 PM (Pacific) this afternoon. As the title suggests, this is a bearish forecast.
Energy Scorecard
- BOM – Down 1500 aMW
- Nov – Up 450 aMW
- Dec – Up 800 aMW
- Jan – Up 1200 aMW
- Feb – Up 1200 aMW
These are material changes in their outlook, before attempting to assess their reasonableness let’s examine the daily energy:
The front contains the greatest deltas to last week and merely reflects the reality of today’s water. The first week of Nov is unchanged from last week’s forecast but beginning on Nov 8 (election day, Trump conspiracy, rigged forecast ???) the forecast begins a long and bearish deviation from last week; in fact, every day, through Feb 20, of this week’s forecast is higher than last week.
What do we know different than what we knew last week? We know that last week had net builds in precip:
But the big builds were on the west side and west side does not matter as far as energy goes; those plants run mostly at hydraulic capacity during this period, to move the energy meter you need east side precip/snow. The MidC received some, Kalispell was up 0.60″, Spokane a bit more, 0.80″, and Boise 0.66″. None of those cities received anything close to what was realized in the preceding week (W1 – W2). So we don’t get it, and this is too much energy to claim its a regulation change.
Before casting further dispersions let’s compare the forecasts to historicals, beginning by day of year:
In this plot we compare energy by date for each of the last four years using the same week of year forecast. Today’s release date was Oct 24, we find the “Oct 24s” for each of the previous three years and compare energy. Clearly 2016 is sailing off into uncharted waters by sporting 2000 MW more dailiy energy until Dec 7, when the 2014 forecast went aberrant. Still, these are material changes and the question one needs to ask is ….”are these reasonable?” Let’s go to snow to answer that:
Huge positive anomalies in the upper Snake, Flathead, and Kootenai but not off the charts as past years realized equivalent big numbers. Also note the Clark Fork is below normal, as is the Salmon. Clearly current snow is not big enough, this early, to warrant the types of energy projections we’re seeing the in this week’s STP.
This chart compares the energy by month using the same “Oct 24” forecast for each of the years. Also, the 5 year average (red column) returns the average of every forecast for that period, not just the same week. The plot suggests November through February will generate the more energy than any of the prior three years.
We think the forecast may be over done but that will depend on how much additional water arrives via rain/snow; what has arrived is not nearly enough to warrant the energy associated with this forecast.