Inflow forecast
model output — not a measurementNOAA’s National Water Model, short-range run issued Sep 13, 3 PM MDT, for the 1 gauged tributary reach feeding Jordanelle Reservoir. The model routes rainfall that has already fallen plus near-term forecast precipitation.
Gauged inflow now
38.8
cfs · measured
Peak next 18h
95
cfs · ~7 AM MDT · modeled
Projected volume
119
acre-feet over 18h · modeled
Net lake effect
-0.11 ft
after 238 cfs out · 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. Flows are projected to rise meaningfully. National Water Model via NOAA/NWS · public domain.
The “net lake effect” nets the projected inflow volume against the water currently leaving the lake (238 cfs — Provo River below the dam, right now), held constant over the horizon, spread over the lake’s estimated surface area (before releases it would be +0.05 ft). It ignores travel time, channel losses, and any change the dam operators make — a scale reference, not a prediction. During floods, watch the live dashboard instead.