Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
665 FXUS66 KSTO 142027 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 127 PM PDT Wed Aug 14 2024 .SYNOPSIS... Near to slightly below normal temperatures persist alongside periodically breezy diurnal winds heading into the weekend. && .Discussion... GOES-West visible satellite imagery reveals mostly clear skies overhead much of interior northern California on this pleasant summer afternoon. Only indication of clouds would be some cumulus starting to bubble up around Lassen National Park, extending north into Oregon. Additionally, some areas of smoke can be observed in far northern California. Dry conditions are largely forecast for the region this afternoon, exception being far northern Shasta County where there is a 10-15% chance of afternoon showers and thunderstorms. This potential increases traveling north into Siskiyou and Oregon. Highs this afternoon will land in the low/mid-90s for most Valley communities, equating to about 2-6 deg F below mid-August climatology. Weak upper-level shortwave along the California-Nevada coast will push inland overnight and into Thursday. This will promote renewed onshore flow over the coming days. A deeper longwave trough will dig behind along the 130 W meridian towards the end of the work week. Temperatures will remain near or slightly below normal as a result, along with increasing onshore winds by Saturday. While minimum afternoon relative humidity values are expected to be in the 25-35% range, will still need to keep a close eye on winds around active wildfires. Along with the ECMWF Extreme Forecast Index highlighting for winds, the National Blend of Models is advertising a 50-70 percent chance of wind gusts exceeding 25 mph in the central/northern Sacramento Valley on Saturday, including near the Park Fire. The approaching trough will also increase thunder chances on Saturday to 15-20 percent for north/west portions of Shasta and Tehama Counties. // Rowe && .EXTENDED DISCUSSION (Sunday THROUGH Wednesday)... Upper level trough will remain along the West Coast with continued periods of onshore breezy winds expected for the second half of the weekend. Through the middle of next week, cluster analysis of the ensembles suggests that this trough will remain quasistationary offshore as it battles with a strengthening, back- building ridge over Texas. Positioning of these synoptic features will ultimately determine potential warming in the extended, but right now, the Climate Prediction Center`s 6-10 day temperature outlook probabilistically favors below-normal to near-normal temperatures for the northern third of California, and increased likelihood of above-normal for southern and eastern California into the Desert Southwest. // Rowe && .AVIATION... VFR conditions will prevail for the next 24 hours, except local MVFR in vicinity of the Park Fire. Surface winds generally below 12 knots, except in the Delta and Sierra Nevada where 15-25 knot winds. Period of breezy to gusty surface winds at Valley sites from around 00Z-06Z with surface gusts 20-25 knots possible. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$