Nipinnawassee, California Weather Forecast Discussion

274
FXUS66 KHNX 210930
AFDHNX
Area Forecast Discussion
National Weather Service Hanford CA
230 AM PDT Sun Sep 21 2025
.KEY MESSAGES...
1. Temperatures warm back up early this week.
2. A slight chance of showers and thunderstorms continues
this weekend in the higher elevations of the Sierra Nevada.
3. More widespread precipitation is in store for the mountains
and desert by Tuesday. There is also a chance of rain returning
to the San Joaquin Valley on Tuesday into Wednesday with a 20 to
40 percent chance of a tenth of an inch of rain.
4. There is at least a 5% chance of excessive rainfall across
Central California on Wednesday and Thursday.
&&
.DISCUSSION...
Lingering moisture and weak instability should be enough for
afternoon showers with a 15%-25% chance of thunderstorms across
the Sierra Nevada. Otherwise, will expect the warming trend in
temperature to continue through the early part of this week. At
this point, a ridge pattern over the area will dominate Central
Californias weather, as we heat up. Yet, an upper low off the
California Coast will support another surge of moisture and
precipitation returns to area around the mid-week period.
Probability of Measurable Precipitation increases toward mid-
week as widespread precipitation will be observed. The pattern
toward Sierra Nevada showers returns toward the end of the week.
Latest ensemble precipitation analysis has the onset of
widespread precipitation starting on Tuesday. A majority of the
probabilistic analysis confines measurable precipitation to the
south-end around Kern County. By Wednesday, 24 hour rain
probabilities show amounts reaching 0.50 (half an inch) with
some extreme values reaching up to 0.75. Therefore, with
probabilities reaching high values, there is at least a 5%
chance of experiencing excessive rainfall on Wednesday. The
northward surge of moisture will present similar conditions on
Thursday as the probability of excessive rainfall continues.
By Friday, the passage of the upper low through Southern
California will change the flow pattern toward a drier one with
a change toward cooler conditions. Probability of Exceedance of
reaching 95 degree by Friday remains at less than 30%. These
percentages increases confidence in high temperatures that are
near normal for this time of year. At the same time, lingering
moisture from the second push of moisture will allow for the
continuation of convection across the Sierra into next weekend.
&&
.AVIATION...
12Z Update:
Across the Sierra Nevada, there is a 10 to 20 percent chance of
thunderstorms from 20Z today through 03Z Monday. MVFR
conditions are possible until 17Z today due to haze, especially
in the eastern San Joaquin Valley. Otherwise, VFR prevails for
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...
None.
&&
$$
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aviation....Molina
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NWS HNX Office Area Forecast Discussion