A series of storms made for a long lasting winter storm over northern California. but lowered with time to some of the west side valley floors.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MFR wrote it up.
A series of storms made for a long lasting winter storm over northern California. At first the snow was limited to higher elevations...but lowered with time to some of the west side valley floors.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Medford, OR wrote its last area forecast discussion before the first event at Dec 23, 9:26 PM PST, 2 hours 4 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
926 PM PST WED DEC 23 2015
.DISCUSSION...EVENING UPDATE. THE LINE OF CONVECTION THAT HAS MOVED
ONSHORE WITH LIGHTNING IS NOT BEING HANDLED VERY WELL BY THE MODELS.
HOWEVER...THE NEXT LINE OF CONVECTION THAT IS MOVING IN FROM
OFFSHORE IS BEING HANDLED WELL BY THE MODELS AND HAVE UPDATED THE
QPF AND SNOW AMOUNTS TO THE LATEST MODEL RUNS. THE BIGGEST CONCERN
IS IF THE LINE OF CONVECTION IS ORGANIZED AND STRONG ENOUGH TO DROP
SEVERAL INCHES IN A SHORT PERIOD OF TIME AND REMAIN ON ROAD SURFACES
THROUGH THE DAY. WILL CONTINUE TO MONITOR AND UPDATE IF IT LOOKS
LINE A SOLID LINE COMING ONSHORE. SVEN
&&
.PREV DISCUSSION... /ISSUED 318 PM PST WED DEC 23 2015/
SHORT TERM...AN ACTIVE AND WET PATTERN CONTINUES THROUGH
CHRISTMAS DAY. THIS EVENING AND TONIGHT, AN UPPER TROUGH WILL
DROP DOWN THE PACNW COAST THEN SHIFT INLAND THURSDAY. IN ADDITION,
A SHORTWAVE AND WEAK SURFACE LOW WILL BRING A FRONT INLAND INTO
SOUTHERN OREGON AND NORTHERN CALIFORNIA TONIGHT AND THURSDAY
MORNING.
THIS FRONT WILL BRING LOW ELEVATION SNOW DOWN TO 800 TO
1500 FT ELEVATION. THIS WILL BRING SNOW ACCUMULATIONS TO WESTERN
VALLEYS AS WELL AS IN THE CASCADES, SISKIYOUS AND INTO NORTHERN
CALIFORNIA AND ACROSS THE EAST SIDE. ALSO THIS FRONT MAY LINGER
THROUGH THURSDAY MORNING ACROSS NORTHERN CALFIORNIA AND MAY BRING
GREATER SNOW IMPACTS TO SISKIYOU COUNTY. A PERIOD OF CONVECTIVE
ACTIVITY IS POSSIBLE WITH THE FRONTAL PASSAGE TONIGHT AND THIS MAY
BRING A BRIEF PERIOD OF MODERATE TO HEAVY SNOW. BEHIND THE FRONT,
EXPECT ADDITIONAL SHOWERS ON THURSDAY. GREATEST IMPACTS FROM SNOW
ARE EXPECTED TONIGHT THROUGH THURSDAY MORNING. OF CONCERN IS THAT
ALL MOUNTAIN PASSES ON INTERSTATE 5 AND ON OTHER AREA HIGHWAYS
WILL IMPACTED BY SNOW AND MANY WEST SIDE VALLEYS WILL BE IMPACTED
BY SNOW. SEE THE WSWMFR PRODUCT FOR DETAILS.
ALONG THE COAST, ALSO EXPECT A SLIGHT CHANCE FOR THUNDERSTORMS
WITH SMALL GRAUPEL TO CONTINUE AS THIS UPPER TROUGH MOVES INTO
PLACE THIS EVENING THROUGH THURSDAY.
MODELS SHOW ON WHETHER THERE WILL BE A BREAK IN SHOWER ACTIVITY
DURING THE DAY THURSDAY OR WHETHER THE AREA WILL CONTINUE TO SEE
SHOWERS. A SHORTWAVE WILL LIKELY BRING ADDITIONAL LIGHT SHOWER
ACTIVITY THURSDAY NIGHT INTO CHRISTMAS MORNING, MAINLY FOR AREAS
FROM THE CASCADES WEST. THE BEST CHANCE FOR ADDITIONAL SNOW
ACCUMULATIONS OF AN INCH OR MORE WILL BE IN THE COASTAL MOUNTAINS
THURSDAY NIGHT AND CHRISTMAS MORNING. SNOW LEVELS DURING THIS
PERIOD WILL BE DOWN 1000 FEET AND LOCALLY DOWN TO 500 FEET.
LINGERING VERY LIGHT SHOWERS DURING THE DAY FRIDAY WILL TAPER OFF
FRIDAY EVENING AS AN UPPER RIDGE BUILDS INTO PLACE.
LONG TERM....CHRISTMAS NIGHT THROUGH NEXT WEDNESDAY...12Z
MODELS ARE IN VERY GOOD AGREEMENT CHRISTMAS NIGHT THROUGH THE
WEEKEND WITH SUBTLE DIFFERENCES SHOWING UP FOR THE EARLY TO MIDDLE
PART OF NEXT WEEK.
WE'LL BE IN A COLD NORTHERLY FLOW ALOFT CHRISTMAS NIGHT BEHIND A
DEPARTING UPPER TROUGH WHICH WILL HEAD THROUGH THE GREAT BASIN
AND CLOSE OFF SOUTH OF THE FOUR CORNERS REGION ON SATURDAY. A
VERY COLD AIR MASS WILL SETTLE IN OVER THE MEDFORD CWA AS AN
UPPER RIDGE BUILDS IN. SATURDAY MORNING'S LOWS WILL BE GENERALLY
5 BELOW TO 5 ABOVE ZERO OVER THE EAST SIDE (EVEN COLDER...WHERE
CLEARING AND FRESH SNOW COVER COINCIDE). LOW TO MID 20S CAN BE
EXPECTED IN THE VALLEYS WEST OF THE CASCADES...THOUGH AREAS OF
FOG AND FREEZING FOG IN SOME LOCATIONS MAY ACTUALLY SERVE TO KEEP
TEMPERATURES A BIT HIGHER. FROST/FREEZE CONDITIONS ARE POSSIBLE
ALONG THE IMMEDIATE COAST AND WE MAY NEED A FREEZE WATCH THERE.
THE UPPER RIDGE WILL MOVE IN OVER THE AREA SATURDAY WITH DRY
WEATHER. BUT IT WILL PROBABLY RIVAL ONE OF THE COLDEST DAYS OF
THE SEASON SO FAR WITH WEST SIDE HIGHS ONLY IN THE MID 30S AND
EAST SIDE HIGHS IN UPPER TEENS AND LOW 20S. THE RIDGE AXIS WILL
SHIFT TO THE SOUTH AND EAST SATURDAY NIGHT, BUT ANOTHER COLD
NIGHT IS EXPECTED WITH LOWS ABOUT 5 TO 15 DEGREES BELOW AVERAGE,
COLDEST EAST OF THE CASCADES.
MODELS YESTERDAY WERE DIVERGENT IN THEIR SOLUTIONS WITH RESPECT
TO THE TIMING OF THE NEXT SYSTEM TO IMPACT THE AREA ON SUNDAY.
THEY ARE NOW IN AGREEMENT SHOWING PRECIPITATION REACHING THE
COAST SUNDAY MORNING, THEN SPREADING INLAND TO THE CASCADES BY
LATE AFTERNOON/EVENING. SNOW LEVELS LOOK TO BE ABOUT 2500-3000
FEET WHEN PRECIPITATION MOVES IN, WHICH WOULD KEEP ACCUMULATING
SNOW ABOVE THE I-5 PASSES NEAR SEXTON SUMMIT. HOWEVER, THE PASSES
THROUGH THE CASCADES AND SISKIYOU SUMMIT MAY SEE SOME WINTER
IMPACTS. THE FRONT WILL BE WEAKENING AS IT MOVES INLAND, SO BY
THE TIME PRECIPITATION REACHES BLACK BUTTE SUMMIT NEAR MOUNT
SHASTA, IT SHOULD BE ON THE LIGHT SIDE. THIS WILL BE A BUSY TRAVEL
DAY, SO TRAVELERS SHOULD KEEPING CHECKING THE FORECAST FOR THE
LATEST UPDATES.
THE ENERGY FROM THIS SYSTEM WILL DIG INTO THE DESERT SOUTHWEST
SUNDAY NIGHT INTO MONDAY, SO PRECIPITATION CHANCES WILL DIMINISH
INTO MONDAY NIGHT IN BETWEEN SYSTEMS.
BY TUESDAY, MODELS DIFFER WITH THE STRENGTH AND TIMING OF THE
NEXT UPSTREAM NORTH PACIFIC SHORT WAVE. THE ECWMF IS DEEPER AND
A BIT FARTHER SOUTH, WHILE THE GFS20 IS FASTER AND A BIT
WEAKER/FARTHER NORTH. DUE TO THE UNCERTAINTY, HAVE MAINTAINED
THE GOING FORECAST OF SLIGHT CHANCE TO CHANCE POPS, HIGHEST
ALONG THE COAST AND DIMINISHING INLAND, ESPECIALLY EAST OF THE
CASCADES. MODELS ARE HINTING AT SHORT WAVE RIDGING BY WEDNESDAY
OF NEXT WEEK. SPILDE
AVIATION...FOR THE 23/00Z TAF CYCLE...SHOWERS CONTINUE ACROSS THE
REGION. ANOTHER LINE OF SHOWERS AND PERHAPS SOME CONVECTION IS
EXPECTED NEAR THE COAST WITH MODEST INSTABILITY. SNOW LEVELS WILL
CRASH TONIGHT BRINGING SOME SNOW TO THE VALLEY FLOORS, SO MFR AND
RBG WILL PROBABLY SEE SOME SNOW ON THE RUNWAYS. OVERALL MVFR AND
IFR FLIGHT RULES THROUGH 18Z TOMORROW. BY THURSDAY AFTERNOON AND
EVENING, VFR CONDITIONS ARE POSSIBLE WITH A SINKING AIR MASS,
ALTHOUGH WE'LL HAVE TO WATCH OUT FOR FOG.
MARINE...UPDATED 630 PM PST WEDNESDAY 23 DEC 2015...HIGH AND
STEEP SWELL CONTINUES IN THE OUTER WATERS. AS THE NEXT WEATHER
SYSTEM COMES THROUGH THURSDAY MORNING AND AFTERNOON, STRONG WINDS
UNDER GALE THRESHOLDS ARE POSSIBLE IN THE OUTER WATERS SOUTH OF
CAPE BLANCO. HEADING INTO FRIDAY, EXPECTING SMALL CRAFT FOR
HAZARDOUS SEAS AS STEEP SEAS CONTINUE. WITH A THERMAL TROUGH
SETTING UP INTO THE WEEKEND, SEAS WILL BECOME RELATIVELY CALM.
-SMITH
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY FOR ORZ029>031.
WINTER STORM WARNING UNTIL 4 PM PST THURSDAY FOR ORZ027-028.
WINTER STORM WARNING UNTIL 4 PM PST THURSDAY ABOVE 2000 FEET FOR
FOR ORZ023-024-026.
HIGH SURF ADVISORY UNTIL 4 AM PST THURSDAY FOR ORZ021-022.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY ABOVE 3000 FEET
FOR FOR ORZ023-024-026.
WINTER STORM WARNING UNTIL 4 PM PST THURSDAY ABOVE 2500 FEET FOR
FOR ORZ025.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY ABOVE 1500 FEET
FOR FOR ORZ021-022.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY FOR ORZ027-028.
WINTER WEATHER ADVISORY UNTIL 7 PM PST THIS EVENING BELOW 2500
FEET FOR FOR ORZ025.
CA...WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY ABOVE 3000 FEET
FOR FOR CAZ080-081.
WINTER STORM WARNING UNTIL 4 PM PST THURSDAY ABOVE 2000 FEET FOR
FOR CAZ080.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY FOR CAZ082.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY FOR CAZ083>085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 10 AM THURSDAY TO 4
AM PST FRIDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING UNTIL 10 AM PST THURSDAY FOR
PZZ350-356-370-376.
CC/MAS/CZSThe national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
A spotter 2SSW Etna at 3500 feet reported 7.5 inches of snow in 10 hours ending at 24/0930 PST. Meanwhile, a spotter in Etna reported 5 inches of snow at 24/1018 PST.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2015Every state in 2015This day in weather historyWarnings in California, December 2015
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 609640.