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567
FXUS66 KSTO 190735
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1235 AM PDT Wed Jun 19 2024

.SYNOPSIS...
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Dry, seasonable weather today with slightly higher relative
humidity helped by onshore flow. A warming trend is expected from
late week and into the weekend.
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&&

Key Points
- Generally seasonable temperatures continue through Thursday,
  much warmer Friday into the weekend.
- Widespread Moderate HeatRisk is expected from Friday through
  Sunday, with some Major HeatRisk in the foothills and Shasta
  county on Saturday.

Short-Term Discussion (Today THROUGH Saturday)...
Ensembles and clusters indicate that weak upper level trough will
remain over NorCal through Thursday. Trough will weaken and
gradually transition into a ridge during the weekend, as upper
high strengthens over the Desert Southwest. This will keep Valley
high temperatures near normal levels today, warming to slightly
above normal Thursday in the 90`s, before heating up to well
above normal levels from the upper 90`s to low 100`s Friday and
Saturday.

Widespread Moderate HeatRisk is expected to start Friday and will
continue through the weekend. Currently probabilities of Sacramento
Valley locations (north of Sacramento metropolitan area) reaching
at least 100 degrees on Friday are 50 to 90%. From the Sacramento
metropolitan area and southward into the northern San Joaquin
Valley, chances are generally lower, at 15 to 50% probability.

Outside of the developing heat, winds will generally be light
helping to reduce critical fire weather conditions a bit, despite
lowering relative humidity Friday and especially Saturday.

&&

.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)...
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Desert SW high continues to build NW into NorCal over the weekend
resulting in widespread triple digit heat in the Central Valley
with 80s to around 102 in the mountains and foothills. Upper low
near VRISL early next week will lower heights some over NorCal
Mon/Tue with upper 90s to around 102 expected in the Central
Valley. Short wave trough progresses east Wednesday allowing high
temperatures to warm back up 2 to 4 degrees.
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&&

.AVIATION...
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VFR conditions over interior NorCal next 24 hrs. Sfc wind mainly
below 12 kts except vcnty of Delta SWly sfc wind 15-25 kts.
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&&

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

$$