024
FXUS66 KSTO 172118
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
118 PM PST TUE DEC 17 2024
SYNOPSIS
DRY WEATHER AND FOGGY MORNINGS ARE EXPECTED THROUGH THE REMAINDER
OF THE WEEK. AN UNSETTLED WEATHER PATTERN IS THEN FORECAST FOR
THE WEEKEND AND INTO THE HOLIDAY WEEK.
DISCUSSION
SOME UPPER LEVEL CLOUD COVER LINGERS OVER INTERIOR NORCAL EARLY
THIS AFTERNOON, WITH FOG FROM THIS MORNING BEGINNING TO LIFT INTO
A WELL DEFINED STRATUS DECK SPANNING PORTIONS OF THE DELTA,
SOUTHERN SACRAMENTO VALLEY, AND NORTHERN SAN JOAQUIN VALLEY. WITH
NORTHERLY WINDS BECOMING BREEZY THROUGH THE AFTERNOON, THIS
STRATUS DECK SHOULD CONTINUE TO SEE SOME GRADUAL NORTH TO SOUTH
EROSION THROUGHOUT THE DAY, BUT THE EXACT EXTENT OF THIS EROSION
REMAINS A LITTLE UNCERTAIN. THIS POTENTIALLY PERSISTENT CLOUD
COVER WILL LIKELY LIMIT DAYTIME HEATING OVERALL, WITH HIGH
TEMPERATURES CLOSER TO THE MID 50S WHERE STRATUS LINGERS.
ELSEWHERE THROUGHOUT THE DELTA, VALLEY, AND FOOTHILLS, HIGH
TEMPERATURES IN THE UPPER 50S TO LOW 60S ARE ANTICIPATED, WITH 40S
TO LOW 50S AT HIGHER ELEVATIONS.
THE AFOREMENTIONED BREEZY NORTHERLY WINDS AT THIS TIME ARE THE
RESULT A SLIGHT PRESSURE GRADIENT REMAINING AS LARGE SCALE RIDGING
CONTINUES TO BUILD IN BEHIND THE DEPARTING SHORTWAVE FROM
YESTERDAY. AS A RESULT, WINDS ARE EXPECTED TO DIMINISH INTO THE
EVENING AND OVERNIGHT HOURS, WITH GENERALLY LIGHT NORTH TO EAST
DAYTIME WINDS AND BREEZY OVERNIGHT/EARLY MORNING DOWNSLOPE WINDS
PREVAILING THROUGH THE REMAINDER OF THE WEEK. THIS STAGNATING
SURFACE PATTERN UNDERNEATH AMPLIFYING RIDGING ALOFT WILL CONTINUE
TO INTRODUCE MORNING FOG POTENTIAL ACROSS PORTIONS OF THE DELTA,
SACRAMENTO VALLEY, AND NORTHERN SAN JOAQUIN VALLEY THROUGH FRIDAY
MORNING. CURRENT HREF PROBABILITIES OF VISIBILITY LESS THAN 0.5
MILES IN THESE AREAS SIT AROUND 60% TO 80% FOR WEDNESDAY MORNING.
SIMILAR TO TODAY, ANY MORNING FOG DEVELOPMENT MAY GRADUALLY LIFT
INTO A STRATUS DECK BY THE AFTERNOON HOURS, WHICH COULD FURTHER
INHIBIT HIGH TEMPERATURES ACROSS AREAS WHERE FOG/STRATUS OCCUR.
OTHERWISE, NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES AND DRY
WEATHER LOOK TO PERSIST ACROSS THE REMAINDER OF THE WEEK, WITH
MORE ACTIVE WEATHER CURRENTLY CONFINED TO THE EXTENDED FORECAST
PERIOD.
EXTENDED DISCUSSION (SATURDAY THROUGH TUESDAY)
THIS WEEKEND WILL LIKELY BE WET, WITH ENSEMBLES AND CLUSTER
ANALYSIS COMING INTO AGREEMENT ON A TROUGH MOVING QUICKLY THROUGH
NORTHERN CALIFORNIA ON SATURDAY. THIS SYSTEM WILL BE FAIRLY WARM,
WITH SNOW LEVELS GENERALLY STAYING ABOVE 6500 TO 7000 FEET. THE
MAJORITY OF PRECIPITATION WILL FALL AS RAIN, WITH THE NBM SHOWING
A 40 TO 65% PROBABILITY OF 1 INCH OR MORE OF RAIN ON SATURDAY IN
THE NORTHERN SACRAMENTO VALLEY, ADJACENT FOOTHILLS, AND NORTHERN
SIERRA/SOUTHERN CASCADES. ELSEWHERE IN THE VALLEY WILL SEE A 20 TO
50% PROBABILITY OF 0.5 INCHES OR MORE. SNOW WILL BE FAIRLY
LIMITED, WITH PROBABILITIES ONLY AT 10 TO 20% FOR 2 INCHES OR MORE
ABOVE 6000 FT. SHOWERS WILL LINGER INTO SUNDAY AS THIS FIRST
TROUGH PROGRESSES EASTWARD OUT OF THE AREA.
CONFIDENCE CONTINUES TO INCREASE IN FURTHER UNSETTLED WEATHER
CONTINUING INTO NEXT WEEK. WHILE DETAILS ARE UNCERTAIN, IT
CURRENTLY LOOKS LIKE MOST OF MONDAY WILL SEE A LULL IN
PRECIPITATION, WITH A NEW TROUGH PROGRESSING INTO NORCAL LATE IN
THE EVENING. THIS WILL BRING RENEWED PRECIPITATION CHANCES TUESDAY
AND FURTHER INTO THE HOLIDAY WEEK. SNOW LEVELS ON MONDAY AND
TUESDAY AT LEAST, REMAIN ABOVE PASS LEVEL, THOUGH THIS MAY CHANGE
LATER NEXT WEEK AS THE TROUGH MOVES ONSHORE, AND COULD POTENTIALLY
IMPACT HOLIDAY TRAVEL. CHECK BACK IN FOR UPDATES AS DETAILS COME
BETTER INTO FOCUS!
AVIATION
SOME MVFR CONDITIONS DUE TO LOW STRATUS/BR/FG FROM SACRAMENTO
SOUTHWARD LINGER THROUGH 23Z. MVFR/IFR AND AREAS OF LIFR
CONDITIONS IN BR/FG ARE THEN EXPECTED TO RETURN AFTER 05Z
WEDNESDAY. SURFACE WINDS GENERALLY LESS THAN 12 KNOTS.
STO WATCHES/WARNINGS/ADVISORIES
NONE.
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