Clearing skies and a cold air mass allowed temperatures to fall below freezing in some areas along the coast.
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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.
Clearing skies and a cold air mass allowed temperatures to fall below freezing in some areas along the coast.
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 30, 9:15 PM PST, 3 hours 45 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
915 PM PST SUN DEC 30 2012
.DISCUSSION...EVENING UPDATE. FOG IS RE-ESTABLISHING IN THE WEST
SIDE VALLEYS THIS EVENING...CURRENTLY IN THE I-5 CORRIDOR FROM THE
WILLAMETTE VALLEY TO GRANTS PASS AND INTO THE ILLINIOS VALLEY.
EXPECT FROST TO FORM IN THE VALLEYS EAST AND WEST...WITH
TEMPERATURES THEN RISING AS FOG THICKENS. CURRENT FORECAST LOOKS ON
TRACK AND WILL NOT UPDATE THIS EVENING.
PREVIOUS DISCUSSION...WEAK UPPER RIDGING IS BUILDING INTO THE
FORECAST AREA THIS AFTERNOON WITH THE RIDGE AXIS MOVING OVERHEAD
TONIGHT. THIS WILL BRING DECREASING CLOUD COVER THIS EVENING WITH
CLEAR TO MOSTLY CLEAR SKIES TONIGHT. THIS COMBINATION ALONG WITH
LIGHT WINDS AND SNOW PACK EAST OF THE CASCADES AND HIGHER TERRAIN
WEST OF THE CASCADES WILL BRING THE COLDEST OVERNIGHT LOWS SO FAR
THIS SEASON. EVEN THE COAST WILL NOT BE IMMUNE TO NEAR FREEZING OR
BELOW FREEZING TEMPERATURES. AS A RESULT A FREEZE WARNING AND FROST
ADVISORY HAS BEEN ISSUED FOR THE COASTAL ZONES. MANY LOCATIONS EAST
OF THE CASCADES WILL HAVE LOWS BELOW ZERO TO SINGLE DIGITS.
TEMPERATURES WEST OF THE CASCADES WILL BE IN THE MID TO UPPER 20S
AND LOW TO MID 30S NEAR AND AT THE COAST. FREEZING FOG IS EXPECTED
TO DEVELOP FOR MOST OF THE WESTSIDE VALLEY LOCATIONS TONIGHT INTO
MOST OF MONDAY MORNING. NOT CONFIDENT IF WE'LL BREAK OUT IN THE
AFTERNOON. IF IT DOES IT MAY ONLY BE FOR AN HOUR OR TWO BETWEEN 4
AND 5 PM PST.
THE RIDGE AXIS QUICKLY SHIFTS EAST MONDAY MORNING AND A WEAK UPPER
TROUGH WILL MOVE IN FROM THE NORTHWEST MONDAY AFTERNOON. THE NAM AND
GFS DIFFER WITH THE TRACK OF THE TROUGH. THE GFS TRACKS IT FARTHER
WEST...THE NAM EAST. THE BIG QUESTION WILL BE THE AMOUNT OF IF ANY
PRECIPITATION....ESPECIALLY WEST OF THE CASCADES. CONFIDENCE IS
HIGHER THE NORTHERN CASCADES AND NORTHERN KLAMATH COUNTY STAND THE
BEST CHANCE OF GETTING PRECIPITATION. WEST OF THE CASCADES THERE IS
MORE UNCERTAINTY. THE NAM SUGGEST NOTHING WILL HAPPEN WHILE THE GFS
SHOWS LIGHT AMOUNTS LATE MONDAY AFTERNOON AND EVENING. THOUGHT THE
BEST WAY TO GO WAS TO GO WITH A SLIGHT CHANCE MAINLY NORTH OF THE
UMPQUA DIVIDE AND NORTHERN CASCADES.
THE UPPER LOW MOVES SOUTH OF THE FORECAST AREA MONDAY NIGHT UPPER
RIDGING AND OFFSHORE FLOW DEVELOPING. SKIES SHOULD CLEAR OUT
AGAIN AND WELL SEE COLD TEMPERATURES OVER MOST OF THE AREA WITH
SINGLE DIGIT READINGS EAST OF THE CASCADES. THE UPPER RIDGE SHIFTS
EAST WEDNESDAY AFTERNOON AND NIGHT AS AN UPPER LOW APPROACHES THE
OREGON COAST. THE NET RESULT WILL BE INCREASING HIGH AND MID CLOUDS
BUT REMAINING DRY. -PETRUCELLI
LONG-TERM...THURSDAY THROUGH MONDAY...MODELS DISAGREE FROM THE
GET-GO IN TERMS OF DETAILS IN THE EXTENDED FORECAST. NAEFS OUTPUT
SHOWS SIGNIFICANT VARIANCE AMONGST ENSEMBLE MEMBERS FROM FRIDAY
ONWARD. THE HOWEVER...THE GENERAL IDEA OF NO MAJOR STORMS THROUGH
SUNDAY IS CONSISTENT ACROSS THE MODELS.
WEATHER IMPACTS IN THE EXTENDED ARE EXPECTED TO BE MINIMAL...MAINLY
IN THE FORM OF FREEZING FOG. WE HAVE FAVORED A BLEND OF THE ECMWF
AND THE GFS...WITH THE ECMWF BEING THE WETTER OF THE TWO WHILE THE
GFS GENERALLY FEATURES RIDGING THE ENTIRE PERIOD. ALL THIS IS
REFLECTED IN TWO PERIODS OF INCREASED CHANCES OF PRECIPITATION OVER
THE WEST SIDE...THURSDAY AND THURSDAY NIGHT...AS WELL AS SATURDAY
INTO SUNDAY. REFORECAST ANALOGS SUGGEST THE EAST SIDE WILL REMAIN
DRY THURSDAY AND FRIDAY...SO HAVE LIMITED POPS THERE. TO HIGHLIGHT
HOW DIFFERENT THE MODELS ARE...THE ECMWF HAS A 553DM CLOSED UPPER
LOW AT THE OREGON COAST THURSDAY NIGHT WHILE THE GFS AND GEM FEATURE
570DM RIDGING. IN SUMMARY...THERE IS LOW CONFIDENCE IN THE DETAILS
OF THE EXTENDED FORECAST. SK
&&
.AVIATION...A DRY AIR MASS IS AFFECTING THE REGION THIS
AFTERNOON...PROVIDING A RELATIVELY GOOD FLYING DAY ACROSS THE WEST
SIDE COMPARED TO RECENT DAYS. MOSTLY VFR CONDITIONS EXIST WEST OF
THE CASCADES...ESPECIALLY ALONG THE COAST AND IN THE ROGUE VALLEY.
THERE ARE SOME LINGERING MVFR CEILINGS NEAR THE COAST RANGE AND
NORTH INTO ROSEBURG. EAST OF THE CASCADES A DECK OF MVFR STRATUS
CEILINGS WILL LIKELY REMAIN AT LEAST PARTIALLY INTACT THROUGH THE
AFTERNOON...BUT COULD CLEAR TONIGHT AS DRIER AIR MOVES INTO THE
AREA. TONIGHT ACROSS THE WEST SIDE...IFR CONDITIONS ARE LIKELY
AGAIN...WITH MODERATE CONFIDENCE IN LIFR FREEZING FOG CONDITIONS AT
MEDFORD LATE TONIGHT INTO MONDAY MORNING GIVEN AMPLE CLEARING THIS
AFTERNOON. SK
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY FROM 1 AM TO 8 AM PST MONDAY FOR ORZ021-022.
FREEZE WARNING FROM 1 AM TO 8 AM PST MONDAY FOR ORZ021-022.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS
FROM 4 AM MONDAY TO 4 AM
PST FRIDAY FOR PZZ350-356-370-376.The national radar mosaic for the moment the first event began.
1 frost/freeze. Local standard time, as filed.
Reported low temperatures ranged from 31 to 34 degrees.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2012Every state in 2012This day in weather historyWarnings in Oregon, December 2012
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: 421235.