CNRFC - Hydrology - River Guidance - Graphical RVF

Location:

TUOLUMNE RIVER - MODESTO (MDSC1)

Latitude: 37.63º N	Longitude: 120.99º W	Elevation: 60 Feet
Location: Stanislaus County in California		Bulletin Group: San Joaquin		River Group: San Joaquin

Issuance Time:

Dec 26 2025 at 9:01 AM PST

Next Issuance:

Dec 26 2025 at 3:00 PM PST

Action/Monitor: 50.5 Feet

Minor Flood: 55.0 Feet

Moderate Flood: 66.0 Feet

Major Flood: 67.0 Feet

Plot Type:

Please Note:
1) Each individual timeseries plotted on the graphical river forecast can be toggled on and off by clicking the legend entry above. If the "Observed (Raw Data)" contains bad data and is toggled off, the plot will scale to the remaining timeseries.

2) At extremely low river flows, the "Observed (Raw Data)" may show readings below the lower end of the available rating table, while the "Observed (Simulated)" will only show values at the bottom of the rating table, creating a potential discrepancy between the two readings.

Observed Data Credit
	Raw streamflow data is provided by the US Geological Survey (USGS). View US Geological Survey (USGS) Data for this station location.

Historical Stage/Flow Data
Note: Water Year 2025 is currently showing peak daily mean values. These will be updated to instantaneous peaks in the coming months.
Water Year	Peak Discharge (cfs)	Stage (feet)	Date
Most Recent 5 Years
2025*	1,420	40.56	Mar 19, 2025
2024*	5,750	48.86	Mar 3, 2024
2023*	10,800	54.79	Mar 31, 2023
2022*	1,710	41.32	Apr 17, 2022
2021*	2,220	42.45	Apr 16, 2021
Historical High Stage/Flow Events (Period of Record - February 1895 to Present)** - Ranked by Flow
1951*	57,000	69.19	Dec 9, 1950
1997*	55,800	71.21***	Jan 4, 1997
1956*	37,600	66.43	Dec 25, 1955
1969*	32,600	65.42	Jan 27, 1969
1895	19,600	20.70	Feb 13, 1895
1940*	18,200	63.10	Mar 27, 1940
* Discharge affected to unknown degree by regulation or diversion Most recent continuous record back to 1943 with segmented periods back to Feb 1895 * Backwater effect caused by debris on railroad trestle 1500 ft downstream of gage

Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Flood Impacts
67.0 Feet	Extensive flooding occurs. Flows in excess of 40,000 cfs could cause extensive damage to residential, industrial and commercial development in Modesto downstream of gage.
55.0 Feet	This is channel capacity through downtown Modesto.

Official 7 Day National Weather Service Forecast (CAZ019)

Today: Mostly cloudy. Rain showers likely and a slight chance of thunderstorms early in the morning, then a chance of rain late in the morning. A chance of rain showers and a slight chance of thunderstorms early in the afternoon, then a chance of rain late in the afternoon. Some thunderstorms may produce heavy rainfall early in the morning. Some thunderstorms may produce heavy rainfall early in the afternoon. Highs 50 to 58. Southeast winds 10 to 20 mph with gusts to around 35 mph.

Tonight: Mostly cloudy with a chance of rain. Lows 41 to 46. Southeast winds 10 to 15 mph with gusts to around 25 mph.

Saturday: Partly cloudy. Highs 48 to 53. Southwest winds up to 10 mph shifting to the northwest in the afternoon.

Saturday Night: Mostly cloudy in the evening then clearing. Patchy fog after midnight. Lows 36 to 41. Northwest winds up to 10 mph.

Sunday: Mostly cloudy in the morning then clearing. Patchy fog in the morning. Highs around 48. Light winds.

Sunday Night: Mostly clear. Lows around 37.

Monday: Mostly cloudy. Highs around 48.

Monday Night: Partly cloudy. Lows around 38.

Tuesday: Mostly cloudy. Highs 47 to 53.

Tuesday Night: Mostly clear. Lows around 39.

Wednesday: Mostly cloudy. Highs 47 to 53.

Wednesday Night: Mostly cloudy with a slight chance of rain. Lows around 42.

New Years Day: Mostly cloudy with a chance of rain. Highs around 50.

Product Disclaimer

This river graphic is not intended to serve as a substitute for official flood watches, warnings, advisories, or statements issued by the NWS Sacramento Weather Forecast Office. Observations are preliminary and subject to change. River levels identified as "forecast" should be consistent with those contained in official NWS products. River levels identified as "guidance" have significant uncertainty due to future weather or reservoir regulation and are provided for planning purposes only.

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Verification - Historical Graphical RVF
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