Inflow forecast

modeled

NOAA’s National Water Model, short-range run issued Sep 29, 9 AM MDT, for the 1 gauged tributary reach feeding Jordanelle Reservoir. The model includes rain that has already fallen plus the near-term rain forecast.

Gauged inflow now

cfs · measured

Peak next 18h

120

cfs · ~Wed 1 AM MDT · modeled

Projected volume

156

acre-feet over 18h · modeled

Net lake effect

−0.12 ft

after 278 cfs out · inferred

Projected flow by tributary reach

Forecast inflow, next 17 hours, all gauged reaches: starts at 61 cfs, peaks at 120 cfs Wed 1 AM (modeled)
Hour	Total (cfs)	Provo (cfs)
Tue 10 AM	61	61
Tue 11 AM	68	68
Tue 12 PM	76	76
Tue 1 PM	84	84
Tue 2 PM	93	93
Tue 3 PM	101	101
Tue 4 PM	107	107
Tue 5 PM	111	111
Tue 6 PM	114	114
Tue 7 PM	116	116
Tue 8 PM	118	118
Tue 9 PM	119	119
Tue 10 PM	119	119
Tue 11 PM	119	119
Wed 12 AM	120	120
Wed 1 AM	120	120
Wed 2 AM	120	120
Wed 3 AM	120	120

ProvoTotal (all gauged reaches)

Dashed lines are forecast. Values are at the gauges; water takes hours to a couple of days to get from there to the lake. Flows are forecast to rise noticeably. National Water Model via NOAA/NWS · public domain.

The “net lake effect” is the forecast inflow volume minus the water leaving the lake now (278 cfs, Provo River below the dam, right now), held steady over the forecast period and spread over the lake’s estimated current surface area (before releases it would be +0.07 ft). It ignores travel time, channel losses and any change the dam operators make, so it gives a sense of scale, not a prediction. During floods, watch the main page instead.