Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 262124
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
124 PM PST Thu Feb 26 2015
A weather system will move into the area on Friday, leading to
cooler and wetter weather into the weekend. The potential exists
for snow impacting some travel in the mountains above 3500 feet,
and more so above 6000 feet.
Latest model runs are in good agreement with incoming system and
therefore no major changes were made to going forecast. System
will move into northern CA late tonight and spread south
throughout the day Friday. Precipitation looks to be convective
in nature which makes overall forecast a bit tricky with QPF and
snow amounts very hit or miss. This line of thinking is mirrored
by latest hires NAM and ARW guidance. Highest totals of half inch
to one inch will be confined to the mountains with generally less
than a tenth of an inch in the valley, outside of any thunderstorm
that does pop up. Isolated thunderstorms still a possibility
(northern valley and mountains on Friday, valley/foothills on Saturday)
given steepening lapse rates and mid-level cooling. Isntability is
marginal though so not expecting anything widespread. Biggest
threat from any thunderstorm will be the possibility of small
hail/graupel. Snow totals still look to be in the 4-8 inch range
above 5500 feet with up to a foot possible at highest elevations.
Snow showers should roll into the mountains during the Friday
afternoon- evening timeframe with snow continuing off and on
through late Saturday. While expected snow totals are on the lower
end, have issued a winter weather advisory above 5000 ft from 1pm
Friday thru 1pm Saturday. Snow will impact what is typically a busy
Friday evening commute into the mountains and snow levels should
be the lowest we`ve seen so far this winter. Chain controls and
travel delays are likely. System begins to move out overnight
Saturday into Sunday with precip tapering off across most areas. A
few showers may linger into Sunday morning across the central
Sierra. Clearing skies and drier weather should rule for the rest
of Sunday. Temperatures will cool with this system with highs in
the valley in the low 60s and mid 30s to 50s in the mountains.
.Extended Discussion (Monday through Thursday)
Models drop another short wave south into the area Monday into
Monday night with minor differences in the track. Given over land
trajectory in northerly flow aloft, QPF looks limited with best
chances for showers over the foothills and mountains with snow
levels around 3000 to 3500 feet. Only a slight chance of showers
expected in the Central Valley. A few lingering showers possible
over the eastern mountains Tuesday otherwise drier weather
expected into the middle of next week as area comes under the
influence of upper ridging.
NWly flow alf as Pac fntl sys drops into Intr NorCal Fri. VFR
conds thru abt 18z Fri then areas MVFR/IFR with lcl LIFR in shwrs
Fri aftn thru Sat. Sn lvls arnd 055 Fri aftn lwrg to arnd 035 Sat.
Isold -TSRAGS poss Fri aftn.
winter weather advisory from 1 pm friday to 1 pm pst saturday
above 5500 feet in the west slope northern sierra nevada...
western plumas county/lassen park.