Scientific Forecaster Discussion
fxus66 khnx 151045
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
245 am PST Fri Dec 15 2017
Synopsis...an area of high pressure off the West Coast
will dominate the weather pattern across central California
for several more days. A cold frontal passage early Saturday
morning could bring a few snow showers to the Sierra crest.
Otherwise, dry weather will prevail over the district through
at least Tuesday night.
Discussion...a dry airmass will continue over the region today,
although the ridge of high pressure now present over the
southwestern U.S. Will give way to a low pressure system that is
expected to arrive during the evening into Saturday morning. This
feature will allow cooler air to filter into central California
from the north with breezy conditions. A few showers are possible
along the Sierra Nevada crest towards Yosemite. Otherwise, dry
conditions will prevail as this system passes over central
California. Daytime highs will lower to closer to average for the
weekend, while overnight lows will also be a bit colder by Sunday
morning, at least in some areas in the mountains that have been
experiencing mild mornings the past several days. Meanwhile,
another upper-level ridge of high pressure will build off the West
The ridge of high pressure will briefly move inland by Monday, so
high temperatures will rise back to above average, similar to
what has been occurring this week. An offshore flow will briefly
return, although it is not expected to be as strong compared to
what has been happening this week. However, overnight lows will
remain quite chilly, especially in the San Joaquin Valley and Kern
County desert areas, as the airmass will be sufficiently dry.
This pattern will continue until Tuesday evening before another
A low pressure system will move over the Great Basin and bring a
slight chance for showers over the Sierra Nevada crest on
Wednesday, although moisture appears limited over this area.
Breezy to locally gusty conditions are possible during Wednesday
afternoon into Thursday. This will allow another episode of cool
northerly flow into central California as the ridge of high
pressure will return to just off the West Coast. Models are in
decent agreement with this pattern overall; however, solutions
continue to differ greatly beyond the next seven days.
widespread MVFR visibility in haze and mist will persist in the San
Joaquin Valley, with areas of IFR and local LIFR/vlifr in fog
developing until 18z Friday. Otherwise, VFR conditions will
prevail over the central California interior during the next 24 hours.
Air quality issues...
on Friday December 15 2017... unhealthy for sensitive groups in
Fresno... Kern... Kings... Madera and Tulare counties.
Fireplace/wood stove burning status is: no burning unless
registered in Fresno... Kern... Kings... Madera... Merced and
Further information is available at valleyair.Org
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.
red flag warning until 8 PM PST this evening caz295>297.