Rosemont, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

176
FXUS66 KSTO 241206
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
406 AM PST Sun Nov 24 2024


.SYNOPSIS...
Brief lull in precipitation for most areas through this
afternoon. Periods of rain and moderate to heavy mountain snow
return tonight through early Wednesday morning with locally
breezy southerly winds. Mostly dry conditions expected on
Thanksgiving continuing into the weekend. Locally breezy northerly
winds by mid-week. Areas of morning frost possible by mid-week.

*Winter Storm Warning: Until 4 AM Wednesday for elevations above
 5500 feet along the Sierra/ Southern Cascades including
 Interstate 80 and Highway 50.

.DISCUSSION...
Latest radar imagery shows generally quiet conditions prevailing
across interior NorCal early this morning. HREF suggest the
potential for some fog across portions of the Valley this morning
(20-40% probability) given mostly clear skies and light winds.
Brief lull in precipitation is expected for most areas through
this afternoon ahead of the next wave of precipitation. Models
show the next round of precipitation approaching the Coastal Range
later this afternoon, then gradually moving across interior
NorCal tonight into early Wednesday morning. Precipitation totals
for the Valley through early Wednesday morning are roughly
0.50-1.25", with 1-2.5" across the foothills.

Periods of moderate to heavy mountain snow return tonight through
early Wednesday morning for the northern Sierra and Southern
Cascades. The National Blend of Models (NBM) suggests a 50-95%
probability of snow amounts greater than 12 inches through early
Wednesday morning across the southern Cascades and northern Sierra
Nevada. Snow levels will initially be around 4000-5000 feet,
increasing to around 5000-6500 feet on Monday, lowering to
4000-5000 feet on Tuesday. Additional snow accumulations of 1 to 3
feet are expected, with up to 4 feet along higher peaks. As a
result, the Winter Storm Warning has been extended through 4 AM
Wednesday above 5500 feet. Snow-covered roads, chain controls and
travel delays are likely which will result in very difficult
travel at times above 5500 feet.

A few lingering mountain showers are expected through Wednesday
morning. Otherwise, drier conditions return to interior NorCal by
mid-week as ensembles depict an upper level ridging building in.
Locally breezy northerly winds develop by mid-week. NBM indicates
a 40-75% probability of wind gusts greater than 25 mph on
Wednesday. NBM projects Wednesday morning lows in the mid 30s
across portions of the northern and central Sacramento Valley,
with the potential for some areas of frost.

.EXTENDED DISCUSSION (Thursday THROUGH Sunday)...

Thanksgiving Day is expected to be dry with light, breezy north
winds as ensembles show an area of broad upper-level ridging and
northwesterly flow aloft over Northern California. Cold low temperatures
may lead to localized patches of frost along the eastern half of
the Valley early Thursday morning. The National Blend of Models
(NBM) indicates a 30 to 60% chance of low temperatures less than
36 deg F. However, breezy north winds developing overnight into
the early Thursday morning hours will keep low temperatures in the
mid to upper 30s along western half of the Valley. Additionally,
Thursday early morning temperatures in the mountains are forecast
to be in the upper teens to mid 20s. Be sure to dress for the
cooler morning weather, and ensure pets and livestock are
protected from the colder temperatures.

NBM attempts to bring in slight chances of rain (15-30%) to areas
south of Interstate 80. Non-impactful very light rain to
sprinkles will be possible over the mountains late Thursday night
into Friday morning. Little to no accumulations are expected.
Otherwise conditions will be mainly dry with daytime temperatures
will remain slightly below normal through Sunday as upper-level
ridging amplifies over the Pacific Northwest.

&&

.AVIATION...

Low stratus and areas of fog may bring periods of MVFR/IFR/LIFR
to portions of the Valley through 17z today. A few low clouds and
fog may still linger across Valley through 22z. VFR conditions
return by 21z. Southerly surface winds will mainly be less than 12
kts. Gusts 15 to 20 kts from the south are expected in the
central and northern Sacramento Valley from 18z today through 11z
Monday. Periodic southerly gusts 15 to 25 kts over the Sierra
through 12z Monday. Scattered showers (60 to 90% chance) may lead
to areas of MVFR/IFR around the northern/central Sacramento Valley
between 23z Sunday-06z Monday.


&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 4 AM PST Wednesday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

$$