Dunlap, California Weather Forecast Discussion

734
FXUS66 KHNX 240830
AFDHNX
Area Forecast Discussion
National Weather Service Hanford CA
130 AM PDT Wed Sep 24 2025
.KEY MESSAGES...
1. Precipitation is in store as showers and thunderstorms will
exist across Central California with the best chance over the
western portion of the area. There is a 15-25 percent chance of
a tenth of an inch of rain over the western side of Central
California.
2. There is at least a 5% chance of excessive rainfall across
Central California today and across the Sierra Nevada on
Thursday.
3. Cooler temperatures starting today and through the weekend.
&&
.DISCUSSION...
The complexities of the closed upper low proved itself this
Tuesday as the trajectory was just west enough to keep most of
the heavier precipitation away. While High-Res Short-range
ensemble had a very good handle on the storm track, uncertainty
in closed lows kept precipitation accumulation to between the
mean value and the 75th percentile. Even with a conservative
approach to precipitation, that proved to be on the high side.
Yet, with ensemble upper-air analysis now showing the closed low
shifting more onshore. Therefore, the onshore push will shift
the plume of higher precip-water toward Central California and
increase the probability of measurable precipitation on
Wednesday.
While the onshore shift of the upper low will push marine air
into Central California and cool things down, the upper low will
increase instability and lift across Central California.
Ensemble average onset of precipitation is around 5AM PDT
(11UTC-12UTC) with widespread precipitation just after sunrise
at 7AM PDT. While heavier precipitation has better chances on
the west side of Central California, will expect widespread
coverage over the Sierra Nevada due to orographic lift under a
more westerly flow aloft. Probability of Precipitation will
shift from the west to the northern portion of Central
California as the upper low transitions through the region. With
the 75th percentile showing 24 hour precipitation in the range
of a quarter to half and inch and at least a 5% of excessive
rain, confidence is high in measurable precipitation for
Wednesday (compared to Tuesday). The upper low is progged to
shift south as wrap-around moisture will present similar
conditions on Thursday as the probability of excessive rainfall
continues. Yet, with the upper low dropping south, will expect
most of the precipitation over the Sierra Nevada.
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:
A 5-15 percent chance of thunderstorms between 20Z today and
03Z Thursday will exist across the San Joaquin Valley and
Sierra Nevada. Otherwise, VFR conditions expected 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.
&&
$$
Public/Aviation....Molina
weather.gov/hanford

NWS HNX Office Area Forecast Discussion