Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Sacramento California
1007 PM PDT Fri may 22 2015
warmer temperatures with scattered mountain showers expected this
weekend into next week.
mountain showers continue this evening over the Sierra will keep
shower chances going overnight. Skies are mostly cloudy over the
area with a moderate onshore flow and winds gusting to 20 mph
Delta to srn SAC/nrn sj valleys. Likely to see another layer of
status cloudiness towards morning srn/SAC valley. Current forecast
is on track no update needed.
a longwave trough remains situated along the West Coast, with
embedded closed upper low now over the Desert Southwest. Showers
and a few thunderstorms have again developed across the interior
northern mountains. Low clouds and fog blanketed the mountains
today, which limited surface instability. Coupled with the fact
that forcing isnt as strong as yesterday, we're not seeing the
level of convective activity as we've seen the last several days.
The short-range, hi-res models (arw, nmm, and hrrr), all suggest a
possibility of showers from the Shasta-trinitys and Mendocino
reaching the Sacramento Valley floor this evening. Otherwise, dry
weather is in store for the lower elevations the next several days
as a more stable airmass comes into place. The mountains will
continue to see showery activity, although Sunday and Memorial Day
may not be quite as widespread as Saturday.
Seasonably cool temperatures will continue today under a moist
airmass. However, a slow and gradual warming trend is expected
through the Holiday weekend. Temperatures should generally be
within a few degrees of normal for the weekend.
Extended discussion (tuesday through friday)
The unsettled weather pattern continues into the extended period,
though there are signs of a break late Thursday and Friday as
shortwave ridging builds in. There is just a slight chance of
showers and thunderstorms along the crest Thursday, with mainly
dry conditions on Friday. High temperatures are expected to warm
from near normal levels on Tuesday to several degrees above normal
by fhursday and Friday. This means locations in the northern
Sacramento Valley could be in the low 90s, with the rest of the
valley in the upper 80s. Whether the ridging can hold into next
weekend is uncertain. Ek
General VFR conditions expected next 24 hours except areas of MVFR
with local IFR conditions over the mountains in the vicinity
showers. Local westerly wind gusts 20-25 kts in the Delta and
northern San Joaquin Valley through around 12z Saturday, and again
returning after 20z.