275
FXUS66 KSTO 020929
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
229 AM PDT Thu May 2 2024

.Synopsis...
Dry and warm weather through Friday with breezy northerly winds.
Active weather returns this weekend as a weather system drops down
bringing showers, mountain snow, isolated thunderstorms, gusty
winds and much cooler temperatures.

&&

Current GOES-West infrared satellite imagery shows a few mid to
high levels clouds passing over interior northern California this
morning. Temperatures are currently in the mid 50s to low 60s in
the Valley, mid 40s to mid 50s in the foothills, and 30s to 40s in
the mountains, valid at 215 AM PDT. Breezy northerly winds will
linger across the area today and into Friday, with wind gusts of
15 to 30 mph. Dry and warm weather continues through Friday. High
temperatures are forecast to be in the 70s to low 80s in the
Valley and foothills, with 50s to 70s in the mountains.

Confidence is increasing for a weather system to drop down from
the Gulf of Alaska, bringing active weather over the weekend.
Widespread precipitation is in the forecast, in the form of
Valley/foothill showers and mountain snow. QPF has trended
higher, and the current guidance from WPC shows amounts of 0.50"
to 1.50" in the Valley, 1" to 2" in the foothills, and 1.50" to 3"
in the mountains from Friday night into Sunday morning. For snow,
the National Blend of Models (NBM) shows a 40 to 80 percent
probability of 6 inches of snow above 6000 feet, with a 45 to 75
percent probability of 8 inches of snow above 6500 feet from
Saturday into early Sunday. Snow levels will initially be high,
around 6000 to 8000 feet late Friday night or early Saturday
morning. As cold air moves in, snow levels will lower through the
day Saturday and then drop to around 3500 to 4000 feet Saturday
night into early Sunday morning. A few lingering showers will be
possible on Sunday, however the majority of precipitation is
expected to fall on Saturday.

Isolated thunderstorms can also be anticipated for Saturday, with
a 15 to 25 percent probability of thunderstorm development. Best
chances would be in the afternoon and evening hours. Expect small
hail, gusty winds, lightning and brief heavy rain with any
thunderstorms that develop. Gusty southwest winds will also develop
across the area on Saturday. Strongest winds will be in the
northern/central Sacramento Valley, northeast foothills, and in
the mountains. The NBM shows a 35 to 75 percent probability of
wind gusts greater than 40 mph in the Valley/foothills, and a 65
to 95 percent probability in the mountains. Much cooler
temperatures return to the area this weekend as the system moves
through, with highs dropping to the 50s and 60s in the Valley and
foothills.

&&

.EXTENDED DISCUSSION (Monday THROUGH Thursday)...
Series of weak embedded vorticity maxima within NWly flow aloft
progged through interior NorCal Monday into Thursday. This will
result in a chance of light showers at times in the northern and
eastern foothills and mountains. NBM showing gradual warming trend
through the extended period with high temperatures near to
slightly above normal Wednesday into Thursday. Areas of gusty
north to east wind will be possible at times next week.

&&

.AVIATION...
VFR conditions over interior NorCal thru 00z Sat. In Central Vly,
areas Nly sfc wind up to 17 kts with lcl gusts to 25 kts possible
til 02z Fri. In foothills/mtns areas N-E sfc wind gusts 20-30 kts
possible next 24 hrs.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$