966
FXUS66 KSTO 151031
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
231 AM PST SUN DEC 15 2024
SYNOPSIS
DRY WEATHER FOR MOST OF THE DAY TODAY, FOLLOWED BY A WEAKER
SYSTEM WITH PRECIPITATION IMPACTS FOCUSED MAINLY IN SHASTA COUNTY,
THE SOUTHERN CASCADES/SIERRA, AND ADJACENT FOOTHILLS BEGINNING
LATE TONIGHT THROUGH TUESDAY MORNING. DRY WEATHER RETURNS BY
MIDWEEK, THEN WET WEATHER POTENTIALLY RETURNS BY THE END OF THE
WEEK.
DISCUSSION
YESTERDAY'S WEATHER SYSTEM IS CONTINUING TO MOVE OUT OF THE AREA
THIS MORNING, WITH THE RETURN OF MOSTLY CLEAR SKIES ACROSS THE
FORECAST AREA. WINDS HAVE WEAKENED AND RETURN TO GENERALLY BELOW
10 MPH ACROSS THE VALLEY FLOOR, AND WILL CONTINUE TO REMAIN
RELATIVELY CLAM THROUGH THE MORNING HOURS. COULD WAKE UP TO SOME
AREAS OF PATCHY FROST THIS MORNING, ESPECIALLY IN THE FOOTHILLS
BELOW THE SNOW LEVELS FROM THE WEEKEND'S STORM. THE RETURN OF
MORNING FOG WILL BE THE PRIMARY TALKING POINT FOR TOMORROW'S
WEATHER, AS THE HREF CONTINUES TO SHOW AROUND A 40-80% CHANCE OF
VISIBILITIES LESS THAN 1/2 MILE FROM REDDING TO MODESTO. WITH THE
RECENT RAINS, CLEAR SKIES, AND LIGHT WINDS, PATCHY DENSE FOG WILL
LIKELY DEVELOP SHORTLY AND CONTINUE THROUGH THE LATE MORNING
HOURS. THE AREA WILL REMAIN MOSTLY DRY AND CLEAR TOMORROW DURING
THE AFTERNOON, THEN AS WE MOVE INTO THE LATE EVENING HOURS, OUR
NEXT QUICK-HITTING WEATHER SYSTEM WILL ENTER THE AREA.
ENSEMBLES DEPICT A SHORTWAVE TROUGH EJECTING FROM A PARENT LOW IN
THE PACNW AND DIGGING INTO NORCAL LATE TONIGHT THROUGH EARLY
TUESDAY. CURRENT PROJECTIONS ON THE TROUGH'S PATH KEEP THE BULK
OF THE PRECIPITATION IN THE NORTHERN SACRAMENTO VALLEY, MAINLY IN
SHASTA COUNTY ALONG WITH THE FOOTHILLS AND SOUTHERN CASCADES AND
SIERRA. THE HIGHER SNOWFALL TOTALS WILL BE IN THE SHASTA COUNTY
MOUNTAINS AND LASSEN NATIONAL PARK, WITH FORECAST TOTALS OF AROUND
5-12 INCHES, LOCALLY UP TO 2 FEET OR MORE AT PEAKS. SNOW LEVELS
WILL BE AROUND 3000 FEET. WITH THE RECENT FORECAST UPTICK IN
SNOWFALL AMOUNTS, A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR
THE MOUNTAINS OF SHASTA AND WESTERN COLUSA COUNTY FROM 10 PM
TONIGHT UNTIL 4 AM TUESDAY. FOR THE REST OF THE AREA, VALLEY
RAINFALL LOOKS TO BE LIGHT COMPARED TO OUR PREVIOUS STORM, WITH
RAINFALL TOTALS OF AROUND 0.10" TO 0.75" INCHES, WITH THE HIGHER
TOTALS IN THE MOUNTAINS/FOOTHILLS AND SHASTA COUNTY. SIERRA SNOW
TOTALS HAVE TRENDED SLIGHTLY UP, WITH AROUND 2 TO 5 INCHES
EXPECTED LATE TONIGHT THROUGH TUESDAY AM. THINGS SHOULD START TO
CLEAR UP AROUND THE AREA AS WE HEAD INTO THE LATE AFTERNOON HOURS
TUESDAY, WITH ONLY A FEW LINGERING ISOLATED SHOWERS AND MOUNTAIN
SNOW SHOWERS POSSIBLE. AS THE SYSTEM VACATES THE AREA, PERIODS OF
BREEZY NORTHERLY WINDS WILL DEVELOP WITH GUSTS AROUND 10 TO 20
MPH POSSIBLE ACROSS THE REGION.
WEDNESDAY, WILL RETURN TO MOSTLY CLEAR AND DRY CONDITIONS ACROSS
INTERIOR NORCAL, AS UPPER LEVEL RIDGING DEVELOPS ONCE AGAIN OVER
THE WESTERN US. HIGH TEMPERATURES WILL CONTINUE TO CLIMB SLIGHTLY,
AND ARE FORECAST TO BE IN THE UPPER 50S TO LOW 60S FOR THE VALLEY.
AREAS OF MORNING FOG MAY REDEVELOP AGAIN MID-WEEK.
EXTENDED DISCUSSION (THURSDAY THROUGH SUNDAY)
THERE WILL BE A QUIET AND DRY WEATHER PATTERN IN STORE FROM MID
TO LATE NEXT WEEK AS BUILDING UPPER LEVEL RIDGING DOMINATES.
WHILE THE BUILDING RIDGE SHOULD SUPPORT GENERALLY CLEAR SKIES,
THIS MAY ALSO PROVIDE A GOOD ENVIRONMENT FOR FOG TO DEVELOP ALONG
WITH COOLER MORNING TEMPERATURES. THIS SHOULD ALSO ALLOW AFTERNOON
HIGH TEMPERATURES TO RISE TO SLIGHTLY ABOVE NORMAL. GENERALLY
LIGHT DIURNAL/TERRAIN DRIVEN WINDS ARE THEN EXPECTED THROUGH THE
REMAINDER OF THE WEEK. ENSEMBLES AND CLUSTERS ARE STILL VARYING
OVER THE RESOLUTION OF A POTENTIAL WEEKEND WEATHER SYSTEM MOVING
IN. THE ECMWF HAS PRECIPITATION MOVING IN LATE SATURDAY WHILE THE
WPC CURRENT QPF IS FOLLOWING THE NATIONAL BLEND OF MODELS (NBM)
RESOLUTION AND BRING PRECIPITATION LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING. EARLY INDICATIONS ARE ANOTHER QUICK-HITTING
SYSTEM, BUT WILL CONTINUE TO MONITOR AND UPDATE AS MOVE THROUGH
THE NEW WORK WEEK.
AVIATION
AREAS OF MVFR IN THE NORTHERN SACRAMENTO VALLEY CURRENTLY, WITH
LOWER CEILINGS PREVAILING. WIDESPREAD AREAS OF MVFR/IFR AND AREAS
OF LIFR AS AREAS OF BR AND FG RETURN AT VALLEY TAF SITES,
,WITH PROBABILITIES OF SURFACE VISIBILITIES LESS THAN 1/2 MILE
ARE AROUND 40-70% THROUGH 20Z TODAY. VFR CONDITIONS RETURN AROUND
20Z SUNDAY WITH LIGHT NORTHERLY WINDS LESS THAN 12 KNOTS.
STO WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 4 AM PST
TUESDAY FOR MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO WESTERN
COLUSA COUNTY-SHASTA LAKE AREA / NORTHERN SHASTA COUNTY.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page