Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 192126
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
226 PM PDT Sun Oct 19 2014
High pressure will provide dry weather and seasonable temperatures
Sunday. Frontal system will provide cooler temperatures and
precipitation chances Monday and Monday night.
Ridge of high pressure will shift eastward overnight.
A weak cold front will move into the coastal range Monday morning
and spread through the interior during the day. The southern end
of the front will move through Sacramento during the afternoon
hours. The front this far south appears like it wont hold together
but may bring some showers this far south. Further north looks
like the better changes of rain. The central core of the low will
move through the interior Monday evening to keep a threat of
showers in the forecast. Once the low moves into the Great Basin
more stable air will filter in behind the system. Instability does
not look that great with this system but any thunderstorms would
likely be limited to the evening hours as the core of the low
moves inland and probably not that widespread.
Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
A large low will form in the Gulf of Alaska by Wednesday.
By Wednesday night some light rain may spread at times across the
far northern interior areas around Shasta county otherwise expect
dry conditions to prevail for most everyone.
.Extended Discussion (Thursday through Sunday)
A trough over the Eastern Pacific and onto the West Coast for the
later part of the week. There is still low confidence in the
extended forecast due to the models varying with the timing and
strength of waves and the trough moving onto the West Coast. The
GFS is still wetter and more progressive than the ECMWF and moves
the trough through on Saturday. The forecast leans more to the
GFS with the threat of precipitation mainly over the Northern
Sacramento valley and surrounding mountains as weak waves may
brush by the north and as the trough moves inland. Temperatures
are expected to remain near to a little above normal with highs in
the mid 70s to low 80s in the Valley and 50s and 60s in the
mountains on Thursday and Friday then a little cooling over the
weekend with the trough moving inland.
Generally VFR conditions tonight with increasing clouds and stronger
southerly winds aft 12z as front moves through the area Monday.
Clouds and precipitation may being local MVFR conditions in the
Valley and MVFR conditions with local IFR over the Mountains after
12z Monday. ISOLD TSRA possible Monday afternoon and evening.