Forest Ranch, California Weather Forecast Discussion

427
FXUS66 KSTO 272002
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
102 PM PDT Sat Sep 27 2025
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.SYNOPSIS...
Cooler temperatures with widespread wetting rain early through
mid this upcoming week across interior NorCal, with the highest
chances within the Coastal Range, southern Cascades, and northern
Sierra. Drier and warmer conditions heading into next weekend.
&&
.KEY MESSAGES...
*  TODAY AND SUNDAY:
- Lingering moisture and forcing from an upper level low brings
   the chance for isolated showers and storms along the Sierra
   Crest south of Highway 50 on Saturday, and Interstate 80 on
   Sunday.
- Cooling trend for daytime highs begins today, with below normal
   temperatures starting Sunday.
* MONDAY THROUGH FRIDAY:
- Good agreement between ensembles that a trough will deepen over
   the eastern Pacific Monday through Wednesday, with increasing
   moisture and forcing across northern California. This trough
   will bring widespread wetting rain potential across interior
   northern CA starting early Monday, and continuing through
   Wednesday.
- Two big pushes of moisture with this upcoming system: the first
   starting early Monday through Tuesday evening, and the second
   continuing overnight Tuesday and through Wednesday. Overall
   forecasted totals have trended down slightly.
- Lingering showers are possible Thursday morning, though there
   is still some uncertainty in the timing of the end of this
   system and any totals for Thursday.
- Probability of 0.25 inches or more of rain between Monday &
   Wednesday:
- In the mountains: 75-95%
- In the Sacramento Valley: 50-85%
- In the northern San Joaquin Valley: 25-45%
- Probability of 1 inch or more of rain between Monday &
   Wednesday:
- In the Coast Range and southern Cascades: 60-85%
- In the northern Sierra: 30-50%
- In the northern Sacramento Valley: 30-60%
- Elsewhere in the Valley: Less than 15%
- With the first push of moisture and forcing on Monday, the
   northern Sacramento Valley, foothills, and mountains all see
   chances for thunderstorms (10-30%) on Monday afternoon and
   evening. Highest chances exist along the Sierra Crest south of
   I-80 (25-30%).
- Friday sees a return to dry weather and a slight warming trend
  into the weekend, with daytime highs reaching closer to normal.
.AVIATION...
VFR conditions prevail through the TAF period, with light winds
and gusts mostly at or below 12 kts until about 18z Sunday.
Southerly winds will pick up at this point, gusting periodically
through 06z Monday up to 20 kts in the central and northern
Sacramento Valley, and up to 15 kts in the southern Sacramento
Valley. Sky coverage begins to increase overnight, with some
uncertain chances for ceilings around 1000 to 2000 ft in the
Sacramento Valley between 10z and 20z Sunday. Otherwise, VFR
conditions throughout the area.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS STO Office Area Forecast Discussion