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.
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*
4,710
13.18
Feb 04, 2025
2024*
5,290
14.07
Feb 04, 2024
2023*
7,150
16.71
Jan 9, 2023
2022*
7,560
16.82
Oct 24, 2021
2021*
178
2.26
Jan 27, 2021
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
1942
11,800
14.60
Feb 06, 1942
1965
11,800
14.96
Jan 05, 1965
* 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
Disastrous 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 Feet
Major Flood Stage. Major flooding throughout the upper Napa Valley with most roads inundated, making travel extremely difficult and unsafe.
20.0 Feet
Moderate 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 Feet
Minor 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 Feet
Monitor 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: Showers and a slight chance of thunderstorms. Lows in the upper 40s to mid 50s. South winds 10 to 20 mph with gusts to around 40 mph.
Saturday: Breezy. Showers and a slight chance of thunderstorms. Highs in the 50s. South winds 20 to 30 mph.
Saturday Night: Showers and a slight chance of thunderstorms. Lows near 50. South winds 10 to 20 mph with gusts to around 35 mph.
Sunday: Showers and a slight chance of thunderstorms in the morning, then showers likely in the afternoon. Highs in the 50s. Southwest winds 10 to 20 mph.
Sunday Night: A chance of showers in the evening, then showers after midnight. Lows in the mid 40s to lower 50s. South winds 5 to 15 mph.
Monday: Showers. Highs in the upper 40s to mid 50s.
Monday Night: Patchy fog. Showers likely. Lows in the 40s.
Tuesday: Mostly cloudy. Patchy fog. A slight chance of showers. Highs in the upper 40s to mid 50s.
Tuesday Night and Wednesday: Mostly cloudy. A chance of showers. Lows in the 30s to upper 40s. Highs in the upper 40s to mid 50s.
Wednesday Night: Partly cloudy. A slight chance of showers. Lows in the mid 30s to lower 40s.
Thursday: Sunny. Highs in the upper 40s to mid 50s.
Thursday Night and Friday: Mostly clear. Areas of frost. Lows in the 30s to lower 40s. Highs in the 40s to mid 50s.
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.
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