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NAPA RIVER - SAINT HELENA (SHEC1)

Latitude: 38.51º N	Longitude: 122.45º W	Elevation: 195 Feet
Location: Napa County in California		Bulletin Group: Russian Napa		River Group: Russian Napa

Issuance Time:

Dec 08, 2025 at 7:54 AM PST

Action/Monitor: 16.0 Feet

Minor Flood: 18.0 Feet

Moderate Flood: 20.0 Feet

Major Flood: 22.0 Feet

Please Note:

Ensemble forecasts produced by CNRFC only consider meteorological uncertainty and do not account for hydrologic uncertainty.

Threshold Exceedance Plot Product Information

CSV Ensemble Files (Data in kcfs): Forecast Group | SHEC1

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		Official Forecast (Deterministic)

		Prob. of Threshold Exceedance
		Model Traces

What information is considered in this forecast?

Verification / Historical Plots
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Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Flood Impacts
24.0 Feet	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)

Today: Mostly cloudy in the morning then becoming sunny. Areas of fog in the morning. Highs in the lower 50s to mid 60s. East winds up to 5 mph and becoming south in the afternoon.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Areas of fog. Lows in the 30s to upper 40s. North winds up to 5 mph.

Tuesday: Partly cloudy in the morning then becoming sunny. Areas of fog in the morning. Highs in the 50s to 60s. North winds up to 5 mph and becoming southwest in the afternoon.

Tuesday Night: Mostly clear in the evening then becoming partly cloudy. Areas of fog. Lows in the 40s to lower 50s. North winds up to 5 mph.

Wednesday: Partly cloudy in the morning then becoming sunny. Areas of fog in the morning. Highs in the upper 50s to lower 70s. Northeast winds around 5 mph and becoming northwest up to 5 mph in the afternoon.

Wednesday Night: Mostly clear in the evening then becoming partly cloudy. Areas of fog. Lows in the 40s to lower 50s.

Thursday and Thursday Night: Mostly clear. Areas of fog. Highs in the upper 50s to lower 70s. Lows in the 40s to lower 50s.

Friday: Partly cloudy in the morning then becoming sunny. Patchy fog. Highs in the upper 50s to lower 70s.

Friday Night and Saturday: Mostly clear. Areas of fog. Lows in the upper 30s to lower 50s. Highs in the mid 50s to upper 60s.

Saturday Night: Partly cloudy in the evening then becoming mostly cloudy. Areas of fog. Lows in the 40s to lower 50s.

Sunday: Mostly cloudy in the morning then becoming partly cloudy. Areas of fog. Highs in the 50s to mid 60s.

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