Inflow forecast

modeled

NOAA’s National Water Model, short-range run issued Sep 29, 11 AM EDT, for the 2 gauged tributary reaches feeding Lake Lanier. The model includes rain that has already fallen plus the near-term rain forecast.

Gauged inflow now

254

cfs · measured

Peak next 18h

263

cfs · ~Wed 3 AM EDT · modeled

Projected volume

383

acre-feet over 18h · modeled

Net lake effect

−0.02 ft

after 613 cfs out · inferred

Projected flow by tributary reach

Forecast inflow, next 17 hours, all gauged reaches: starts at 254 cfs, peaks at 263 cfs Wed 3 AM (modeled)
Hour	Total (cfs)	Chattahoochee (cfs)	Chestatee (cfs)
Tue 12 PM	254	184	70
Tue 1 PM	254	183	71
Tue 2 PM	253	181	72
Tue 3 PM	252	179	73
Tue 4 PM	252	177	75
Tue 5 PM	253	176	77
Tue 6 PM	254	175	79
Tue 7 PM	255	174	81
Tue 8 PM	256	173	83
Tue 9 PM	258	173	85
Tue 10 PM	259	173	87
Tue 11 PM	260	173	88
Wed 12 AM	261	173	89
Wed 1 AM	262	173	89
Wed 2 AM	263	173	90
Wed 3 AM	263	173	90
Wed 4 AM	263	172	91
Wed 5 AM	263	172	91

ChattahoocheeChestateeTotal (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. National Water Model via NOAA/NWS · public domain.

The “net lake effect” is the forecast inflow volume minus the water leaving the lake now (613 cfs, Chattahoochee below Buford Dam, right now), held steady over the forecast period and spread over the lake’s estimated current surface area (before releases it would be +0.01 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.