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: Apr 19 2025 at 8:02 AM PDTNext Issuance: Apr 20 2025 at 9:00 AM PDT
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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Day:  
Year:  
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To view other verification locations, use our Historical Graphical River Forecast Interface.
Historical Stage/Flow Data
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2023
24,500
52.24
Mar 27, 2023
2022
1,190
33.41
Dec 31, 2021
2021
1,770
34.50
Feb 1, 2021
2020
3,120
37.40
Oct 2, 2019
2019
11,800
45.31
Jun 5, 2019
 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
1938*
--
50.50
Jun 13, 1938
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)
Tonight: Clear. Lows 46 to 52. Northwest winds up to 10 mph.

Sunday: Sunny. Highs 74 to 82. Northwest winds up to 10 mph.

Sunday Night: Clear. Lows 47 to 53. Northwest winds up to 10 mph.

Monday: Sunny. Highs 76 to 84. Northwest winds up to 10 mph.

Monday Night: Clear. Lows 50 to 58. Northwest winds up to 10 mph.

Tuesday: Mostly sunny. Highs 78 to 87.

Tuesday Night: Clear. Lows 47 to 53.

Wednesday: Sunny. Highs 72 to 81.

Wednesday Night and Thursday: Mostly clear. Lows 45 to 51. Highs 70 to 80.

Thursday Night: Partly cloudy. Lows 45 to 51.

Friday through Saturday: Mostly clear. Highs 64 to 74. Lows 45 to 51.
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.