CNRFC - Hydrology - River Guidance - Graphical RVF

*** IMPORTANT *** Week of June 16 - Website Data Outage - Due to a major computer upgrade the week of June 16, nearly all data on the CNRFC web site will not be updated. We anticipate the down time to be approximately 4 days. The latest deterministic hydrologic forecasts for official forecast points will continue to be available at the National Water Prediction Service during this time.

Location:

SAN JOAQUIN RIVER - VERNALIS (VNSC1)

Latitude: 37.68º N	Longitude: 121.27º W	Elevation: 35 Feet
Location: San Joaquin County in California		Bulletin Group: San Joaquin		River Group: San Joaquin

Issuance Time:

Jun 14 2025 at 7:23 AM PDT

Next Issuance:

Jun 15 2025 at 9:00 AM PDT

Action/Monitor: 24.5 Feet

Minor Flood: 29.0 Feet

Moderate Flood: 32.0 Feet

Major Flood: 37.3 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
Water Year	Peak Discharge (cfs)	Stage (feet)	Date
Most Recent 5 Years
2024*	10,300	18.12	Mar 6, 2024
2023*	34,400	29.82	Mar 19, 2023
2022*	2,600	10.83	Dec 29, 2021
2021*	2,470	10.76	Jan 31, 2021
2020*	6,130	14.29	Dec 9, 2019
Historical High Stage/Flow Events (Period of Record - Jul 1922 to Present) - Ranked by Flow
1951*	79,000	27.75	Dec 09, 1950
1997*	75,600	34.88	Jan 05, 1997
1969*	52,600	34.55	Jan 27, 1969
1938*	51,200	26.64	Mar 16, 1938
1956*	50,900	26.89	Dec 25, 1955
1983*	45,100	31.49	Mar 07, 1983
* Discharge affected by regulation or diversion

Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Flood Impacts
37.29 Feet	Stages above 37.3 feet results in flooding outside the levees. Top of levee.
29.6 Feet	Homes along east bank of river on Airport Court in Manteca experience flooding.
26.0 Feet	Severe seepage occurs outside the levees. The area covered by seepage will increase as the river stage rises.
24.5 Feet	Monitor Stage - water reaches the toe of levee.
21.0 Feet	Seepage begins into crop area outside of levees.

Official 7 Day National Weather Service Forecast (CAZ019)

Tonight: Clear. Lows 50 to 58. Northwest winds up to 10 mph with gusts to around 20 mph.

Sunday: Sunny. Highs 85 to 93. Northwest winds up to 10 mph.

Sunday Night: Clear. Lows 50 to 58. Northwest winds up to 10 mph with gusts to around 20 mph.

Monday: Sunny. Highs 83 to 91. Northwest winds up to 10 mph with gusts to around 20 mph.

Monday Night: Clear. Lows 51 to 57. West winds up to 15 mph.

Tuesday: Sunny. Highs 87 to 94.

Tuesday Night: Clear. Lows 57 to 63.

Wednesday and Wednesday Night: Clear. Highs 92 to 100. Lows 55 to 63.

juneteenth and Thursday Night: Clear. Highs 86 to 94. Lows 52 to 62.

Friday through Saturday: Clear. Highs 79 to 89. Lows 50 to 57.

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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To view other verification locations, use our Historical Graphical River Forecast Interface.