National Weather Service California Nevada River Forecast Center Department of Commerce National Oceanic and Atmospheric Administration National Weather Service

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SAN JOAQUIN RIVER - PATTERSON (PATC1)
Latitude: 37.49º NLongitude: 121.08º WElevation: 97 Feet
Location: Stanislaus County in CaliforniaBulletin Group: San JoaquinRiver Group: San Joaquin
Issuance Time: Nov 17 2025 at 8:28 AM PSTNext Issuance: Nov 17 2025 at 3:00 PM PST
Action/Monitor: 48.0 FeetMinor Flood: 54.7 FeetModerate Flood: 57.3 FeetMajor Flood: 58.3 Feet

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
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Raw streamflow data is provided by the California Department of Water Resources.
View California Department of Water Resources Data for this station location.

Verification - Historical Graphical RVF
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To view other verification locations, use our Historical Graphical River Forecast Interface.
Historical Mean Daily Stage/Flow Data
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2025* 3,474 37.43 Mar 23, 2025
2024* 5,740 41.64 Mar 7, 2024
2023* 24,500 52.24 Mar 27, 2023
2022* 1,190 33.41 Dec 31, 2021
2021* 1,770 34.50 Feb 1, 2021
 Historical High Stage/Flow Events (Period of Record - Oct 1969 to Present) - Ranked by Flow
1983* 28,700 51.26 Mar 4, 1983
2006* 27,612 50.97 Apr 10, 2006
2017* 25,600 51.71 Feb 22, 2017
1980* 24,900 50.57 Feb 25, 1980
2023* 24,500 52.24 Mar 27, 2023
1986* 23,000 49.65 Mar 18, 1986
* Discharge affected by regulation or diversion
** Most recent continuous record back to Oct 1969 with segmented periods back to Apr 1938
Location Photographs
ESRI™ Locator Map
Flood Impacts
58.3 FeetStages above 58.3 feet result in flooding outside the levee. Top of levee.
Official 7 Day National Weather Service Forecast   (CAZ019)
Today: Rain showers early in the morning, then a chance of rain showers in the late morning and afternoon. A slight chance of thunderstorms late in the afternoon. Highs 52 to 60. South winds 10 to 15 mph. Gusts up to 35 mph decreasing to 25 mph in the afternoon.

Tonight: Mostly cloudy. A slight chance of rain showers in the evening. Lows 42 to 48. South winds up to 10 mph.

Tuesday: Mostly cloudy in the morning then becoming partly cloudy. Highs 53 to 61. Light winds.

Tuesday Night: Mostly clear. Lows 43 to 49. Light winds.

Wednesday: Partly cloudy. Highs 54 to 62. Light winds.

Wednesday Night: Mostly cloudy with a chance of rain showers. Lows 46 to 52.

Thursday: Mostly cloudy with a chance of rain showers. Highs 54 to 60.

Thursday Night: Mostly cloudy with a chance of rain showers. Lows 43 to 49.

Friday: Partly cloudy. Highs 56 to 62.

Friday Night through Sunday: Mostly clear. Lows 40 to 47. Highs 57 to 63.
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.