Inflow forecast
model output — not a measurementNOAA’s National Water Model, short-range run issued Sep 14, 4 PM MST, for the 3 gauged tributary reaches feeding Lake Powell. The model routes rainfall that has already fallen plus near-term forecast precipitation.
Gauged inflow now
—
cfs · measured
Peak next 18h
4,403
cfs · ~7 AM MST · modeled
Projected volume
6,474
acre-feet over 18h · modeled
If it all reached the lake
+0.05 ft
if it all reached Powell · inferred
Projected flow by tributary reach
Dashed = forecast. Values are at the gauges, not at the lake — water takes hours to a couple of days to travel downstream from the gauges to the lake. National Water Model via NOAA/NWS · public domain.
The “naive lake effect” spreads the projected inflow volume over the lake’s estimated current surface area, ignoring travel time, channel losses, upstream storage decisions, and releases — it is a scale reference, not a prediction of the actual lake level. During floods, watch the live dashboard instead.