Herndon, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

029
FXUS66 KHNX 091801
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
1101 AM PDT Wed Jul 9 2025


.KEY MESSAGES...
1. Temperatures near season averages across the region today before
a gradual warm up into the triple digits later this week.

2. Low RH values 15 to 25 percent will stretch across much of the
San Joaquin Valley and Sierra Nevada with values 5 to 10 percent in
the Mojave Desert. RH will decrease over the region later in the
week with warming temperatures.

&&

.DISCUSSION...
Upper level disturbance riding over Northern California is now
pushing into the Great Basin and out of the area. This shift
will allow the ridge of high pressure over the Desert Southwest
to retrograde and shift back toward the West Coast in the coming
days. While the ridge of high pressure will build over the West
Coast by the end of the week, the ridge is expected to remain
flat with minimal amplification. Therefore, while triple digit
heat toward the end of the week, the intensity of the heat will
be such that values will remain well below any records for the
period. In addition, the flow around the flat ridge will prevent
any significant monsoonal moisture push to surge toward Central
California as the region remains dry during the upcoming heat
event. Therefore, by the start of the weekend, a heat wave will
reach Central California with some overnight recovery as minimum
temperatures bottom out in the mid 60s. Little change in seen
as the ridge pattern will remain into early next week.

While the ridge pattern builds back onto the West Coast,
ensemble Probability of Exceedance (PoE) of reaching 100 degrees
remains below 30% today. Thursday marks the transition period
at which time the PoE jumps up to a range between 50% and 90%,
with the higher end on the west side of the San Joaquin Valley
along the Interstate-5 corridor. At that point, triple digits
are mostly scattered with less of a chance over the Highway-99
corridor. Also, by Thursday, the Kern Desert maxs out its PoE
with values above 90% for the duration of the period. Friday
shows both the San Joaquin Valley and Kern Desert having
probabilities in the 90% and above range. At that point,
confidence in widespread triple digits increases for the start
of the next heat wave. While Thursday will see some highs
reaching 100 degrees, Friday has a higher likelihood of having
values reach the 103 degree and above mark. By Friday and the
weekend, PoE of 103 degrees is in the range of 70% to 90% which
increases confidence in having a heat wave. Little change in PoE
values is observed through early next week as triple digit
temperatures will exist through day 7.

The ridge pattern solution will favor some heat as the flow
around the ridge will hinder monsoonal moisture from reaching
Central California. Therefore, dry and hot will be the main
message during the short term as light diurnal winds will also
be seen during the period.

&&

.AVIATION...
18Z Update:

VFR conditions will prevail for the next 24 hours across the Central
California Interior.

&&

.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