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

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NAPA RIVER - SAINT HELENA (SHEC1)
Latitude: 38.51º NLongitude: 122.45º WElevation: 195 Feet
Location: Napa County in CaliforniaBulletin Group: Russian NapaRiver Group: Russian Napa
Issuance Time: Feb 08 2025 at 8:27 AM PSTNext Issuance: Feb 09 2025 at 9:00 AM PST
Action/Monitor: 16.0 FeetMinor Flood: 18.0 FeetModerate Flood: 20.0 FeetMajor Flood: 22.0 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 US Geological Survey (USGS).
View US Geological Survey (USGS) 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 Stage/Flow Data
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2023*
7,150
16.71
Jan 9, 2023
2022* 7,560 16.82 Oct 24, 2021
2021*
178 2.26 Jan 27, 2021
2020*
696
4.31
Dec 7, 2019
2019*
9,570
19.50
Feb 27, 2019
 Historical High Stage/Flow Events (Period of Record - Jun 2000 to Present)* - Ranked by Flow
2006*
18,300
23.61
Dec 31, 2005
1986
16,900***
18.52
Feb 17, 1986
1997 13,100 17.70 Jan 1, 1997
1956
12,600
15.17
Dec 22, 1955
1963 12,300 15.30 Jan 31, 1963
* Discharge affected by regulation or diversion
** Most recent continuous record back to Jun 2000 with segmented periods back to Oct 1929
*** Flood of record at old gage site
Location Photographs
ESRI™ Locator Map
Flood Impacts
24.0 FeetDisastrous Flooding. Widespread flooding across upper Napa Valley with travel essentially impossible. The peak water level during the flood of 12/31/2005 measured 23.6 feet.
22.0 FeetMajor Flood Stage. Major flooding throughout the upper Napa Valley with most roads inundated, making travel extremely difficult and unsafe.
20.0 FeetModerate Flood Stage. Moderate flooding of the lower portions of Silverado Trail along the reach. Inundation of low lying residential areas along the east river bank in the vicinity of Pope Street Bridge. Secondary and many primary roads inundated; most major cross roads inundated and unsafe to pass.
18.0 FeetMinor Flood Stage. Minor flooding of low lying agricultural areas along river begins. Low lying rural residential areas immediately adjacent to the river and some secondary roads affected.
16.0 FeetMonitor Stage. WFO Monterey may issue a Flood Watch-based products to cover Napa Valley regional flood potential at this stage.
Official 7 Day National Weather Service Forecast   (CAZ506)
Rest of Tonight: Clear. Areas of frost and patchy fog after midnight. Lows in the upper 20s to lower 40s. Northwest winds 5 to 10 mph.

Sunday: Sunny. Widespread frost and patchy dense fog in the morning. Highs in the 50s to lower 60s. Northwest winds 5 to 10 mph.

Sunday Night: Mostly clear. Areas of frost and patchy fog after midnight. Lows in the upper 20s to lower 40s. North winds up to 5 mph.

Monday: Partly cloudy. Widespread frost in the morning. Highs in the 50s. Northeast winds up to 5 mph and becoming southwest in the afternoon.

Monday Night: Partly cloudy. Areas of frost and patchy fog after midnight. A slight chance of drizzle and very light freezing drizzle after midnight. Lows in the 30s to lower 40s. Northwest winds 5 to 10 mph.

Tuesday: Partly cloudy. Areas of frost. A slight chance of drizzle and very light freezing drizzle. Highs in the upper 40s to mid 50s.

Tuesday Night: Mostly cloudy. A chance of rain and light freezing rain. Lows in the 30s to lower 40s.

Wednesday: Rain and a chance of light freezing rain. Highs in the upper 40s to mid 50s.

Wednesday Night and Thursday: Rain. Lows in the 30s to upper 40s. Highs in the 50s.

Thursday Night: Patchy fog. Drizzle likely and rain. Lows in the 30s to upper 40s.

Friday: Mostly cloudy. Patchy fog. A chance of rain. Highs in the 50s to lower 60s.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Patchy fog. A slight chance of rain. Lows in the upper 30s to mid 40s.

Saturday: Mostly cloudy. Areas of fog. A chance of rain. Highs in the mid 50s to lower 60s.
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 San Francisco Bay Area-Monterey 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.