Area Forecast Discussion
FXUS66 KSTO [Sacramento/WFO CA] 042159 AFDSTO ∨
FXUS66 KSTO 042159 AFDSTO [HEAD]
National Weather Service Sacramento California 2:59pm PDT Fri Sep 4 2015 ∨
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 259 PM PDT FRI SEP 4 2015 [HEAD]
Synopsis. The chance of showers and/or thunderstorms to the northern mountains will diminish by Saturday morning, with Lassen Peak potentially seeing some light snow. Breezy north winds over the weekend warming to near normal by Sunday. A little warmer than normal next week under upper level high pressure. ∨
.SYNOPSIS... THE CHANCE OF SHOWERS AND/OR THUNDERSTORMS TO THE NORTHERN MOUNTAINS WILL DIMINISH BY SATURDAY MORNING, WITH LASSEN PEAK POTENTIALLY SEEING SOME LIGHT SNOW. BREEZY NORTH WINDS OVER THE WEEKEND WARMING TO NEAR NORMAL BY SUNDAY. A LITTLE WARMER THAN NORMAL NEXT WEEK UNDER UPPER LEVEL HIGH PRESSURE. [DISC]
Discussion (tonight through Monday). Upper trough passing through Northern California this afternoon with isolated showers and thunderstorms over Siskiyou County and into northern Shasta County. The thunderstorm threat will likely extend into the evening, while the shower threat continues overnight over the southern Cascades and the extreme northern Sierra (Shasta and Plumas Counties). The upper low will drop southward with enough instability and cold air to generate light snow over Lassen Peak tonight. The upper low is then projected to swing quickly eastward into the Great Basin Saturday inducing a northerly surface gradient behind the departing low that will bring breezy north to northeast winds to much of the forecast area over the weekend. Winds will be strongest down the west side the Sacramento Valley and adjacent foothills, and the overnight to mid morning hours down the Sierra. Monday begins the gradual building of the ridge with warming temperatures. (Jclapp) ∨
.DISCUSSION (TONIGHT THROUGH MONDAY)... UPPER TROUGH PASSING THROUGH NORTHERN CALIFORNIA THIS AFTERNOON WITH ISOLATED SHOWERS AND THUNDERSTORMS OVER SISKIYOU COUNTY AND INTO NORTHERN SHASTA COUNTY. THE THUNDERSTORM THREAT WILL LIKELY EXTEND INTO THE EVENING, WHILE THE SHOWER THREAT CONTINUES OVERNIGHT OVER THE SOUTHERN CASCADES AND THE EXTREME NORTHERN SIERRA (SHASTA AND PLUMAS COUNTIES). THE UPPER LOW WILL DROP SOUTHWARD WITH ENOUGH INSTABILITY AND COLD AIR TO GENERATE LIGHT SNOW OVER LASSEN PEAK TONIGHT. THE UPPER LOW IS THEN PROJECTED TO SWING QUICKLY EASTWARD INTO THE GREAT BASIN SATURDAY INDUCING A NORTHERLY SURFACE GRADIENT BEHIND THE DEPARTING LOW THAT WILL BRING BREEZY NORTH TO NORTHEAST WINDS TO MUCH OF THE FORECAST AREA OVER THE WEEKEND. WINDS WILL BE STRONGEST DOWN THE WEST SIDE THE SACRAMENTO VALLEY AND ADJACENT FOOTHILLS, AND THE OVERNIGHT TO MID MORNING HOURS DOWN THE SIERRA. MONDAY BEGINS THE GRADUAL BUILDING OF THE RIDGE WITH WARMING TEMPERATURES. JCLAPP [DISC]
Extended discussion (Tuesday through Friday) upper ridging over the Eastern Pacific will gradually build over interior Northern California through the extended forecast period. Dry weather will result with above normal temperatures. Highs temperatures in the Central Valley are expected from the mid 90s to around 100° in the north, with mostly 80s to low 90s for the mountains and foothills. ∨
.EXTENDED DISCUSSION (TUESDAY THROUGH FRIDAY) UPPER RIDGING OVER THE EPAC WILL GRADUALLY BUILD OVER INTERIOR NORTHERN CALIFORNIA THROUGH THE EXTENDED FORECAST PERIOD. DRY WEATHER WILL RESULT WITH ABOVE NORMAL TEMPERATURES. HIGHS TEMPERATURES IN THE CENTRAL VALLEY ARE EXPECTED FROM THE MID 90S TO AROUND 100 DEGREES IN THE NORTH, WITH MOSTLY 80S TO LOW 90S FOR THE MOUNTAINS AND FOOTHILLS. [DISC]
Aviation. VFR [Visual Flight Rules] conditions next 24 hours except for potential MVFR [Marginal Visual Flight Rules] ceilings in Shasta Mountains and extreme northern Sierra into tonight. Typical northerly winds develop Sat behind trough. (Jclapp) ∨
.AVIATION... VFR CONDITIONS NEXT 24 HRS EXCEPT FOR POTENTIAL MVFR CIGS IN SHASTA MOUNTAINS AND EXTREME NORTHERN SIERRA INTO TONIGHT. TYPICAL NORTHERLY WINDS DEVELOP SAT BEHIND TROUGH. JCLAPP [AVIA]
STO [Sacramento/WFO CA] Watches/Warnings/Advisories
.STO WATCHES/WARNINGS/ADVISORIES... NONE. [WARN]
04 Sep 8:02pm PDT
Tonight Mostly clear, with a low around 55°. Calm wind becoming east 5 to 8 mph after midnight.
Saturday Sunny, with a high near 73°. East wind around 8 mph becoming WSW in the afternoon.
Saturday Night Clear, with a low around 48°. WNW wind 6 to 10 mph becoming ENE in the evening.
Sunday Sunny, with a high near 79°. ENE wind 6 to 10 mph becoming SW in the morning.
Sunday Night Clear, with a low around 53°. West wind around 7 mph becoming ENE in the evening.
Labor Day Sunny, with a high near 82°.
Monday Night Clear, with a low around 55°.
Tuesday Sunny, with a high near 83°.
Tuesday Night Clear, with a low around 58°.
Wednesday Sunny, with a high near 84°.
Wednesday Night Clear, with a low around 61°.
Thursday Sunny, with a high near 86°.
Thursday Night Clear, with a low around 62°.
Friday Sunny, with a high near 85°.
Mostly clear, with a low around 55. Calm wind becoming east 5 to 8 mph after midnight.
Sunny, with a high near 73. East wind around 8 mph becoming west southwest in the afternoon.
Clear, with a low around 48. West northwest wind 6 to 10 mph becoming east northeast in the evening.
Sunny, with a high near 79. East northeast wind 6 to 10 mph becoming southwest in the morning.
Clear, with a low around 53. West wind around 7 mph becoming east northeast in the evening.
Sunny, with a high near 82.
Clear, with a low around 55.
Sunny, with a high near 83.
Clear, with a low around 58.
Sunny, with a high near 84.
Clear, with a low around 61.
Sunny, with a high near 86.
Clear, with a low around 62.
Sunny, with a high near 85.