Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 282100
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
200 PM PDT FRI OCT 28 2016
Frontal system continues to move out of the area this afternoon and
evening with residual showers and isolated Thunderstorms in its
wake. Weak high pressure will temporarily move over the region on
Saturday before another system moves in on Sunday. This system will
be colder than the first and will produce advisory level amounts of
snow to the higher elevations of the Sierra Nevada.
Upper level trof pushing through Central California today with
the associated surface low currently near Carson City/Reno. Surface
analysis and visible satellite imagery show the cold front moving
east of the district with partial clearing already occurring. The
upper trof is still behind the surface low and expected to push
east of Central California tonight. In addition, a secondary
surface low continues to spin offshore with a further influx of
moisture from subtropical origins. With the clearing already
occurring, enough moisture and instability may exist this
afternoon for isolated to possibly scattered convection through
the early evening hours. Furthermore, enough upper level dynamic
support may exist to assist in this late afternoon/early evening
Weak ridging behind the trof on Saturday may allow for lingering
light showers to exist, mainly over the mountains, through the
first half of the day. While the dry period will be short lived,
current weather progs show a much colder system dropping in from
the Gulf of Alaska late Saturday into early Sunday morning. Being
a much deeper trof, models prog a better surge of subtropical
moisture ahead of the system with similar precipitation as those
seen with the latest storm event. The difference will be the
amount of cold air driving trough Central California this weekend.
Snow levels by Sunday Morning will drop to near 8000 feet and
possibly brief heavy snow over the higher terrain during the same
time. Issued a Winter Weather Advisory which will be valid from
late Saturday night through Sunday evening. While 6 to 12 inches
of snow will be common during the 24 hour period from Yosemite to
Kings Canyon, isolated spots could see a much as 17 inches during
the same time. In addition, models show strong winds possible over
the higher terrain during the storm event. This may produce
blowing snow and making travel difficult over the high country.
The strong winds support the issuance of the advisory.
Longer range model progs follow-up the deeper trof with a weaker
storm system pushing through on Tuesday. Models currently show
the best dynamics remaining over Northern California and skirting
the Merced County/Yosemite area. Will concentrate on the next
storm, which could also produce thunderstorms across the north
valley... north of Kern County...during the day on Sunday. By
midweek, models showing good consensus on dropping the weak
disturbance toward Yuma, AZ by Wednesday and placing the district
under a ridge pattern. Ensembles along with GFS mod-trend keeps
the district dry from Wednesday through Friday. Therefore, after
Tuesday`s event, the district may see a dry periods with fog
becoming the main concern for the later periods.
Local IFR/MVFR ceilings can be expected along the east side of the
San Joaquin Valley and adjacent foothills through 16z Saturday.
Areas of MVFR ceilings will also occur along the north facing
slopes of the Tehachapi mountains between 03z and 16z Saturday.
VFR conditions will prevail elsewhere across the central California
interior during the next 24 hours.
.AIR QUALITY ISSUES...
The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.
Winter Weather Advisory from 11 PM Saturday to 11 PM PDT Sunday
above 8000 feet for the Sierra Nevada from Yosemite to Kings