FXUS66 KSTO 062122
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
122 PM PST Thu Mar 6 2025
SYNOPSIS...
Lingering showers through the early afternoon then dry weather
returns for Friday through Sunday with northerly flow. Active
weather then returns next week bringing periods of major travel
impacts from rain, wind and mountain snow impacts across Northern
CA.
.DISCUSSION
...
Isolated showers continued this morning with lingering chain
controls over the Sierra. As we progress through the day,
conditions will continue to dry and see the inevitable end to our
Winter Weather Advisory later today. Looking past this event, we
can expect dry weather through the weekend with temperatures
getting into the mid 60s to low 70s by Sunday. Friday will see
breezy winds with gusts up to 15-25 MPH in the Valley but no
significant impacts expected.
We continue to look next week for more active weather bringing
periods of moderate to very heavy snowfall, rain, gusty winds, and
possible isolated thunderstorms. Be sure to check the latest
update at weather.gov/sto as we get closer to the event.
.EXTENDED DISCUSSION
(Monday THROUGH Thursday)...
Ensemble guidance and cluster analysis continue to exhibit high
confidence in an active weather pattern returning to the forecast
over the extended forecast period with multiple weather systems
moving through Monday and again Tuesday through Thursday bringing
along rain, wind and mountain snow impacts to interior northern
California. Here is a look at some 72 hour probabilities from the
National Blend of Models (NBM) ending 5 AM Thursday:
Probability of Rain > 1 inch: 55-95%
Probability of Rain > 2 inches: 15-30% (Valley), 45-80%
(foothills)
Probability of Mountain Snow > 48 inches: 40-85%
Probability of Mountain Snow > 60 inches (N of I-80): 40-70%
Probability of Mountain Snow > 60 inches (S of I-80): 15-45%
Probability of Wind Gusts > 40 mph: 50-85% (Valley/Foothills)
Probability of Wind Gusts > 55 mph: 45-75% (Foothills/Mountains)
In addition to the higher probabilities from the NBM, the Extreme
Forecast Index (EFI) is also highlighting the potential for these
impacts, especially in the middle of next week. Although there is
still some uncertainty in exact details such as snow levels,
precipitation amounts and wind speeds, confidence is high in the
active weather over the extended forecast period for Interior
NorCal. Stay tuned for more information as we get closer and plan
ahead for wet, cool and windy weather!
(Listed Snow Probs are for above 5000 feet but still fair amount
of uncertainty regarding exact snow levels!)
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