043 FXUS66 KSTO 232021 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 121 PM PDT Mon Jun 23 2025 .DISCUSSION... .SYNOPSIS... Mountain shower and thunderstorm chances from Interstate 80 southward this afternoon lead into a shift toward seasonable temperatures accompanied by dry weather and periodically breezy onshore winds through the remainder of the week. A warming trend with areas of Moderate HeatRisk is then anticipated heading into the weekend. && .KEY MESSAGES... * The Week Ahead: -Areas of elevated fire weather concerns across the northern Sacramento Valley from low humidity and periodically breezy winds. -Slight 10-15% chance of isolated mountain thunderstorms this afternoon from Interstate 80 southward. -Seasonable temperatures expected, with Delta, Valley, and foothills high temperatures in the 80s to 90s and 70s to 80s at higher elevations. * The Weekend: -Warming trend into the weekend with high temperatures across the Delta, Valley, and foothills in the 90s to lower triple digits and 80s to low 90s expected at higher elevations. --Areas of Moderate HeatRisk on Saturday become widespread by Sunday. -Dry weather continues with lessening onshore flow. --Daytime minimum humidity in the teens to low 20s with more limited overnight recovery, especially across foothills and higher terrain .Changes from previous forecast... -No changes from the previous forecast && .AVIATION... VFR conditions persist at TAF sites next 24 hours. North to west winds become predominantly south to west by 00z Tuesday generally remaining 12 kts or less, although some gusts to 20 kts in Delta and vicinity 00z to 08z. Isolated mountain shower/thunderstorm chances after 21z from Interstate 80 southward. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$