Projected Precipitation for Mariposa 0.50"- 1.00"
Projected Precipitation for Yosemite Valley 0.75"- 1.50"
August 20, 2023 - National Weather Service Hanford Office officials report atmospheric moisture associated with Hilary will move northward into Central California today and tonight.
Record rainfall will cause flooding of streams, creeks, and low-lying areas in the Kern County desert.
Flash flooding is likely in the Kern County mountains and Southern Sierra Nevada.
The heaviest rain will fall this afternoon and tonight.
Area Forecast Discussion
National Weather Service Hanford CA
144 AM PDT Sun Aug 20 2023
.SYNOPSIS...
More widespread precipitation is forecast for today, with the
heaviest amounts in Tulare and Kern County -- including the
Mojave Desert -- where catastrophic flash flooding is
conceivable. Rainfall associated with Hilary will mostly exit the
region by late Monday. A few residual showers and thunderstorms in
the Sierra Nevada are forecast Tuesday through the end of this
week.
&&
.DISCUSSION...
Scattered showers and thunderstorms will continue overnight
tonight in mainly southern and western portions of the Central
Valley and the mountains along the west side of the valley. By
sunrise, expect heavier precipitation due to the outer bands of
Tropical Storm Hilary to arrive into Kern County, including the
mountains and desert, while more precipitation will pass over the
southern San Joaquin Valley. Heavy rain with thunderstorms will
spread northward through the day today and last until at least
this evening. Gusty northerly winds will develop this afternoon
and continue overnight into Monday morning in the Kern County
desert, with gusts as high as 60 mph. The peak of this wind event
will be late afternoon through late evening as the central low
associated with TS Hilary moves just to the east. Winds will
initially be from the northeast this afternoon and will shift to
the northwest by later this evening.
Precipitation amounts for today will be highest over Kern County
and the Sierra Nevada into Tulare County. However, rainfall
amounts in the Sierra north of Tulare County will still be
significant. Probabilities of 2 inches of more range from 25 to 40
percent in the south valley to 50 to 80 percent in the Kern
County mountains and desert, as well as the Sierra in Tulare
County. The best chances for this much rain will be in the desert
zones, and there is up to a 40 percent chance that 3 inches of
rain will fall today into the evening.
Rainfall associated with Hilary will continue while decreasing on
Monday, as the peak of this event lasts until this evening. The
afternoon/evening shower and thunderstorm threat will persist
over the Sierra on Tuesday until at least Friday. Milder
temperatures will last until Tuesday before the drying and warming
occurs by Wednesday through Saturday. Afternoon highs will be
seasonably warm mainly in the 90's at the warmest locations
during this period.
&&
.AVIATION...
Areas of MVFR and local mountain obscuring IFR conditions in and
near showers and thunderstorms in the Sierra Nevada and adjacent
foothills. Showers and thunderstorms will also impact the
remainder of the Central CA interior with areas of MVFR. Northerly
winds with gusts around 50 kts in the Kern County desert during
23Z Sunday thru 07Z Monday. Otherwise, VFR conditions will
prevail through at least the next 24 hours.
&&
.AIR QUALITY ISSUES...
None.
&&
.CERTAINTY...
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.html for additional information
and/or to provide feedback.
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Monday evening for CAZ314-316-322-328>339.
High Wind Warning from 2 PM this afternoon to 5 AM PDT Monday
for CAZ337>339.
Source: NWS
