*** 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.
Napa River - Saint Helena (SHEC1)River Forecast Plot
Combination chart with 4 data series.
Forecast Posted: 06/03/2025 at 7:58 AM PDT ● Graphic Created: 06/03/2025 at 8:03 AM PDT
The chart has 1 X axis displaying Time. Range: 2025-05-29 15:00:00 to 2025-06-08 15:00:00.
The chart has 2 Y axes displaying Precipitation (In.) and Precipitation (In.).
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End of interactive chart.
Chart
Combination chart with 7 data series.
The chart has 1 X axis displaying Observation / Forecast Time (Pacific Local Time). Range: 2025-05-29 08:00:00 to 2025-06-08 08:00:00.
The chart has 2 Y axes displaying Stage (Feet) and Flow (Cubic Feet per Second).
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End of interactive chart.
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.
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
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 Today: Sunny. Highs in the upper 60s to lower 80s. Southwest winds 10 to 20 mph.
Tonight: Mostly clear in the evening then becoming partly cloudy. Patchy fog after midnight. Lows in the 40s to upper 50s. Southwest winds 10 to 20 mph.
Wednesday: Sunny. Highs in the lower 70s to mid 80s. Southwest winds 10 to 20 mph.
Wednesday Night: Mostly clear except patchy fog after midnight. Lows in the upper 40s to mid 50s. Southwest winds 10 to 20 mph.
Thursday: Mostly cloudy in the morning then becoming sunny. Patchy fog in the morning. Highs in the upper 60s to lower 80s. Southwest winds 10 to 20 mph.
Thursday Night: Mostly clear except patchy fog. Lows in the upper 40s to mid 50s.
Friday: Partly cloudy in the morning then becoming sunny. Highs in the lower 70s to mid 80s.
Friday Night: Mostly clear except patchy fog. Lows in the 40s to upper 50s.
Saturday and Saturday Night: Mostly clear. Highs in the 70s to 80s. Lows in the 40s to upper 50s.
Sunday: Partly cloudy in the morning then becoming sunny. Highs in the 70s to 80s.
Sunday Night: Mostly clear in the evening then becoming partly cloudy. Patchy fog. Lows in the 40s to upper 50s.
Monday: Partly cloudy in the morning then becoming sunny. Highs in the 70s to 80s.
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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