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FGUS76 KMTR 312019
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CAZ502>506-010830-

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1219 PM PST Fri Jan 31 2025

...LIGHT TO MODERATE RAINFALL WILL RESULT IN AN INCREASED
POTENTIAL FOR RAPID RIVER RISES ON NORTH BAY CREEKS AND STREAMS...

* WHAT...The first significant atmospheric river of the calendar
  year is forecast to impact Northern California over the next 5
  days. While uncertainty exists, the probabilities of exceeding
  flood thresholds have increased across several rivers in the
  North Bay. The current forecast brings unsettled weather along
  with periods of light to moderate rainfall to the region through
  the first half of next week with the biggest impact expected
  over the North Bay. The first storm that is currently moving
  into the North Bay is expected to prime the soils over the
  weekend resulting in quicker and more noteworthy rises of area
  streams and creeks for the second round of rain that is progged
  to impact the North Bay Monday into Tuesday. The higher
  elevations of the North Bay will likely see around 8 to 9 inches
  of (storm total) precipitation while North Bay valleys see
  around 4 to 6 inches of (storm total) precipitation.

  Mainstem rivers are forecast to remain below flood stage,
  however the exceedance probabilities (of rising above flood
  stage) for reaching flood thresholds are increasing Tuesday and
  Wednesday across the North Bay. The Russian River at Guerneville
  - GUEC1 has a 34% probability of exceeding the Action/Monitor
  stage, a 25% probability of exceeding the Minor Flood stage, and
  a 10% probability of exceeding the Moderate Flood stage. SHEC1-
  Napa near Saint Helena has a 27% probability of exceeding the
  Action/Monitor stage and a 16% probability of exceeding the
  Minor Flood stage. APCC1- Napa near Napa has a 30% probability
  of exceeding the Action/Monitor stage, 14% probability of
  exceeding the Minor Flood stage, and a 10% probability of
  exceeding the Moderate Flood stage . A few other rivers to keep
  an eye on that show higher probability of reaching
  Action/Monitor or Minor flood stage according to the latest
  CNRFC forecast are CTIC1 - Laguna De Santa Rosa at Stony Pt Rd
  near Cotati has a 89% probability of reaching Action/Monitor
  Stage and a 60% probability of reaching Minor flood stage. MWEC1
  - Mark West Creek at Mirabel Heights now has a 93% probability
  of reaching Action/Monitor Stage and a 52% probability of
  reaching Minor flood stage. GEYC1 - Russian River at Geyserville
  has a 48% probability of reaching Action/Monitor Stage and a
  25% probability of reaching Minor flood stage.

* WHERE...Sonoma and Napa Counties. Latest model guidance
  suggests the North Bay will receive the greatest accumulation of
  precipitation with the heaviest rainfall expected over the
  North Bay coastal range and mountains.

* WHEN...Saturday through Wednesday. Light to Moderate rainfall
  expected over the North Bay Saturday through Wednesday. The
  heaviest rainfall accumulation is expected Monday into Tuesday
  with the greatest river rises expected Tuesday into Wednesday.

* ADDITIONAL DETAILS...In addition to the moderate rainfall and
  localized ponding of water in low-lying or poorly drained areas,
  such as freeway offramps. Locally strong and gusty winds may
  result in downed trees, and potential power outages.

Confidence is high that we will receive rainfall from this system
however, confidence is moderate with respect to the exact
location and timing of the most intense rainfall. Details
regarding this storm will likely change as the system nears.
Therefore, stay tuned to the latest forecast for the most up to
date weather information.

$$