Inflow forecast

modeled

NOAA’s National Water Model, short-range run issued Sep 29, 10 AM CDT, for the 1 gauged tributary reach feeding Canyon Lake. The model includes rain that has already fallen plus the near-term rain forecast.

Gauged inflow now

cfs · measured

Peak next 18h

cfs · ~Wed 2 AM CDT · modeled

Projected volume

122

acre-feet over 18h · modeled

Net lake effect

−0.01 ft

after 154 cfs out · inferred

Projected flow by tributary reach

Forecast inflow, next 17 hours, all gauged reaches: starts at 77 cfs, peaks at 84 cfs Wed 2 AM (modeled)
Hour	Total (cfs)	Guadalupe (cfs)
Tue 11 AM	77	77
Tue 12 PM	78	78
Tue 1 PM	78	78
Tue 2 PM	79	79
Tue 3 PM	80	80
Tue 4 PM	80	80
Tue 5 PM	81	81
Tue 6 PM	82	82
Tue 7 PM	82	82
Tue 8 PM	83	83
Tue 9 PM	83	83
Tue 10 PM	83	83
Tue 11 PM	84	84
Wed 12 AM	84	84
Wed 1 AM	84	84
Wed 2 AM	84	84
Wed 3 AM	84	84
Wed 4 AM	84	84

GuadalupeTotal (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 (154 cfs, Guadalupe at Sattler, right now), held steady over the forecast period and spread over today’s surveyed surface area (TWDB) (before releases it would be +0.02 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.