259 FXUS66 KSTO 140956 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 156 AM PST Tue Jan 14 2025 .SYNOPSIS... Dry weather with near to above normal high temperatures continue. North to east winds weaken across the Valley and foothills, lingering gusts in the mountains through Wednesday. Colder overnight low temperatures with areas of frost expected this week. && .DISCUSSION... Mostly clear conditions across interior NorCal this morning, with high stratus being observed across the northern Sierra and a thin layer reported at SMF. Winds have generally calmed around the region as well, with wind gusts generally below 20 mph except in the foothills/mountains, where Jarbo Gap is observing gusts of 39 mph currently. North to east wind gusts will continue, although weaker than yesterday`s winds, in the mountains, with forecast speeds sitting around 20-45 mph. Upper level pattern looks to remain on track to previous forecasts, as ridging remains firmly in place in the PacNW, and a closed cut-off low is present off-shore SoCal. Resultant Rex Block pattern will remain in place until at least Friday, where the closed low will move inland and phase with a trough near the Rockies. In this pattern, we will continue to see mostly dry and clear conditions across interior NorCal, with generally light north winds. The biggest sensible weather impact will be cold overnight/morning low temperatures across the Valley. This morning through Friday morning, Valley lows are forecast to be in the mid to upper 30s. The probabilities of reaching freezing (32 F) remain relatively low, with the NBM advertising around a general 25% chance tonight through Friday morning. With the cold overnight/morning temperatures and lighter winds in the forecast, areas of patchy frost may develop in the Valley through the short term forecast period. High temperatures look to remain seasonable to slightly above climatological normal, with Valley highs forecast to be in upper 50s to mid 60s through Thursday. As the closed low moves further inland and the Rex Block pattern breaks on Friday, temperatures will cool slightly to the 50s across the Valley, and cooler 30s to low 50s for the higher elevations. && .EXTENDED DISCUSSION (Saturday THROUGH Tuesday)... High amplitude EPAC upper ridging continues off the West Coast through the weekend. Ridge axis shifts inland Monday, then weak short wave moves through it Tuesday. Areas of gusty north to east wind possible, late Sunday into Monday. Dry weather expected with near normal high temperatures. && .AVIATION... Mainly VFR conditions over interior NorCal next 24 hrs. Sfc wind generally below 12 kts except areas of N-E sfc wind 15-25 kts in N and E foothills/mountains thru 20z Wed. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$