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023
FXUS66 KSTO 252008
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
108 PM PDT Tue Jun 25 2024

.SYNOPSIS...
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Isolated showers and thunderstorms will remain possible across
interior NorCal through early this evening. Seasonable, dry, and
periodically breezy weather then persists through the remainder of
the week into the weekend.
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&&

Key Points
- Areas of Moderate HeatRisk today, becoming primarily Minor
  HeatRisk mid-week into the weekend.
- Slight chance of isolated thunderstorms through this evening, best
  chances over the Sierra Crest south of Highway 50.
- Potential for another warming trend by early next week.

Short-Term Discussion (Today THROUGH Friday)...

As of early this afternoon, GOES-West satellite imagery continues to
depict a few plumes of mid level moisture ejecting across interior
NorCal. Resultant radar imagery is showing some scattered convection
across the region as well, but given the height of the moisture
aloft, little, if any, precipitation is reaching the ground. A few
updrafts have been strong enough to produce a few isolated lightning
strikes across the Valley and foothills though. As a result, there
remains a 10 to 15% chance of isolated thunderstorm activity in the
Valley and foothills through the early evening hours.

At this time, the strongest instability on the order of a few
hundred J/kg remains confined along the Sierra, generally south of
the I-80 corridor. This will be the primary corridor for additional
thunderstorm development this afternoon and evening, with a 15 to
30% probability of thunderstorm development. These mountain
thunderstorms will have a better chance at some light rainfall
accumulation and small hail production, but the primary hazards will
be gusty and erratic winds as well as potential for new fire starts
from lightning.

Otherwise, high temperatures today are expected to settle in the
upper 80s to 90s throughout the Valley and foothills, with 70s to
80s at higher elevations. An upper level trough is then expected to
eject through the Pacific Northwest toward the Intermountain West
from Wednesday into the end of the week. This will bring lowering
heights aloft and generally cooler, near normal temperatures through
the end of the week and into the weekend. Cooler is still relative,
however, as afternoon high temperatures are still expected to reach
the 80s to mid 90s in the Valley and foothills, with 70s to 80s
persisting at higher elevations. Given the relative stability in the
flow pattern aloft, breezy to occasionally gusty, late day south to
west winds are expected to persist as well.

&&

.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)...

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Latest cluster analysis continues to show rather uniform
agreement on another trough ejecting through the Pacific Northwest
over the weekend. This will work to keep temperatures steady and
seasonable, while onshore flow and breezy late day winds persist
through the weekend at this time. The aforementioned trough does
look to take a slightly further southward track compared to its
predecessor. Additionally, ensemble guidance is indicating that
ridging aloft will begin to build in across the eastern Pacific,
inducing a period of northwesterly flow and height rises aloft
moving into early next week. A resultant warming trend is
anticipated during this time frame, with some signals at a period
of breezy to gusty north- northwesterly winds on Monday as well.
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&&

.AVIATION...

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VFR conditions expected to prevail across interior NorCal next 24
hours. Isolated showers and thunderstorms possible through 03z,
with highest chances along the Sierra. Otherwise, breezy south to
west surface winds, with occasional gusts to 20 kts in the Valley
through 03z and gusts to 25 kts in the Delta and vicinity
persisting overnight.
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&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$