Very strong downslope winds occurred along the base of the blue mountains early in the morning. One mesonet site near Cayuse measured a wind gust of 82 (MPH).
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 PDT wrote it up.
Very strong downslope winds occurred along the base of the blue mountains early in the morning. One mesonet site near Cayuse measured a wind gust of 82 (MPH). Damage reports from the city of Weston that shingles had been blown off a roof and some power lines were down.
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 Pendleton, OR wrote its last area forecast discussion before the first event at Dec 9, 9:25 PM PST, 3 hours 35 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
925 PM PST WED DEC 9 2015
.UPDATE...THE LATEST RADAR WAS SHOWING AN AREA OF CLOUDS AND SHOWERS
ENTERING THE COAST OF OREGON AND IS FORECAST TO RAPIDLY MOVE EAST
AND EFFECT OUR WESTERN ZONES TONIGHT. THE SHOWERS WILL MOVE INTO THE
REMAINDER OF THE AREA OVERNIGHT ALONG WITH BREEZY TO WINDY
CONDITIONS BY THE MORNING RUSH HOUR. MEANWHILE COLDER AIR LINGERS
ALONG THE EAST SLOPES OF THE WASHINGTON CASCADES AND PERIODS OF SNOW
IS EXPECTED WITH ACCUMULATIONS BETWEEN 3 TO 5 INCHES. OTHERWISE THE
TEMPS AND SKY CONDITIONS WERE ADJUSTED AND THE PRESENT SHORT TERM
FORECAST APPEARS ON TRACK FOR NOW.
&&
.AVIATION...LCL MVFR CONDITIONS WILL BECOME AREAS OF MVFR AND LCL
IFR CONDITIONS ESPECIALLY IN AND NEAR SHOWERS AFTER 08Z FOR TAF
SITES KRDM AND KBDN. THESE CONDITIONS CAN BE EXPECTED AFTER 10Z FOR
THE REMAINDER OF THE SITES. IN ADDITION BREEZY TO WINDY CONDITIONS
CAN BE EXPECTED WITH GUSTS APPROACHING 40 KTS AFTER 12Z AND
CONTINUING THROUGH THURSDAY.
&&
.PREV DISCUSSION... /ISSUED 211 PM PST WED DEC 9 2015/
SHORT TERM...TONIGHT THROUGH SATURDAY...FORECAST AREA IS BETWEEN
SYSTEMS AT THIS TIME FOLLOWING THE PASSAGE OF A COLD FRONT THIS
MORNING. THE NEXT SYSTEM WILL ARRIVE LATE TONIGHT AND EARLY THURSDAY
AS A WARM FRONT FOLLOWED QUICKLY BY A COLD FRONTAL PASSAGE. IT WILL
ALSO USHER IN SOME WINDY SOUTHERLY WINDS OVER PORTIONS OF THE AREA
OVERNIGHT AND THURSDAY. SOME COLD AIR POOLED ALONG THE EAST SLOPES
OF THE CASCADES WILL LOWER SNOW LEVELS TO AROUND 2000 FEET SO
EXPECTING SOME ACCUMULATING SNOW OF 3 TO 5 INCHES.
FOLLOWING THE COLD FRONT WE WILL SETTLE INTO A COOLER AND UNSETTLED
WEATHER PATTERN AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
REGION PRODUCING OCCASIONAL SHOWERS FROM PASSING SYSTEMS. SNOW
LEVELS WILL BE DROPPING DOWN TO AROUND 3000 FEET AND THERE WILL BE
SOME ACCUMULATING SNOW IN THE MOUNTAINS. THE NEXT WELL ORGANIZED
SYSTEM WILL ARRIVE LATE SATURDAY AS ANOTHER WARM FRONT ARRIVES.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...WIND AND MODERATE
PRECIPITATION WILL LIKELY CONTINUE UNDER WESTERLY FLOW SATURDAY
EVENING INTO SUNDAY...WITH BEST CHANCES OVER THE MOUNTAINS. BY
SUNDAY AFTERNOON AND EVENING THE FLOW WILL SHIFT TO A MORE NORTHERLY
TRACK AS A TROUGH OF COLD AIR DEEPENS OVER THE WESTERN CONUS. SNOW
LEVELS WILL QUICKLY DROP OVER A 24 HOUR PERIOD FROM ABOUT 4000FT MSL
TO AROUND 1500FT BY MONDAY AFTERNOON. COLD AIR WILL CONTINUE
THROUGH THE REST OF THE EXTENDED...AN FROM THIS POINT THE SNOW
LEVELS WILL LIKELY REACH THE BASIN FLOOR BY TUESDAY AFTERNOON
ONWARD. THERE MAY BE A FEW ISOLATED SPOTS ALONG THE COLUMBIA RIVER
THAT STAY JUST WARM ENOUGH TO RECEIVE A VERY COLD RAIN OR RAIN/SNOW
MIX.
POPS WILL BE THE CHALLENGE AS MODELS HAVE STRUGGLED WITH WHERE THEY
WANT PRECIPITATION AND HOW MUCH...AS WELL AS EMBEDDED DISTURBANCES
THAT COULD PROVIDE ENHANCED PRECIPITATION.
OVERALL...WILL CONTINUE THE TREND OF SLIGHT CHANCE OVER THE LOWER
ELEVATIONS...AND CHANCE TO LIKELY OVER THE MOUNTAINS. ALTHOUGH IT'S
TOO SOON TO TELL...SOME MODELS HAVE HINTED AT ENOUGH PRECIPITATION
TO ALLOW FOR 3+ INCHES OF SNOW OVER SHORTER DURATIONS (LESS THAN 6
HOURS) FOR THE EXTENDED. WILL HAVE BETTER ESTIMATES AS WE APPROACH
THE NEAR TERM AND START ADDING QPF TO THE FORECAST. WEBER
AVIATION...00Z...VFR CONDITIONS EXPECTED TO PREVAIL FOR FOR THE
NEXT 24 HOURS...WITH BREEZY CONDITIONS PERSISTING AT MOST TAF SITES
THROUGH THIS EVENING. WIND GUSTS WILL STILL RANGE FROM 25 TO 35 KTS
AT TIMES. THERE WILL STILL BE SOME AREAS OF RAIN AFTER 06Z THAT
COULD ALLOW FOR LOCAL MVFR/IFR CIGS/VIS BUT WILL AMEND TAFS AS
NECESSARY FOR CONDITIONS. WEBER
HYDROLOGY...THE YAKIMA AND NACHES RIVERS WILL CONTINUE TO RISE
TONIGHT AT UPPER LOCATIONS AND THEN THE FLOOD CREST SHOULD BE
TRAVELING DOWNSTREAM TO THE PARKER AND KIONA FORECAST POINTS
THURSDAY AND FRIDAY. WITH THE 3-5 INCHES OF RAIN LAST NIGHT...THE
SMALLER STREAMS IN WESTERN KLICKITAT, KITTITAS AND YAKIMA COUNTIES
ARE ALSO SEEING SOME FLOODING. AREAL FLOOD ADVISORIES AND WARNINGS
WILL REMAIN IN EFFECT OVERNIGHT FOR THOSE AREAS. THE LOWER SNOW
LEVELS EXPECTED LATE TONIGHT AND FOR THURSDAY WILL HELP ALLEVIATE
THE FLOODING ON THE SMALLER STREAMS. FLOOD WARNINGS FOR THE YAKIMA
AND NACHES RIVER FORECAST POINTS WILL CONTINUE OVER THE NEXT SEVERAL
DAYS. ML
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 41 51 37 46 / 60 80 20 20
ALW 45 53 40 49 / 30 100 20 20
PSC 41 51 35 46 / 40 100 10 10
YKM 36 47 32 42 / 60 100 10 10
HRI 41 51 36 47 / 60 80 10 10
ELN 33 41 30 40 / 50 100 10 10
RDM 38 47 33 44 / 100 40 30 20
LGD 36 46 33 41 / 70 100 20 30
GCD 38 45 34 40 / 100 70 30 20
DLS 40 50 36 48 / 100 80 20 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...WINTER WEATHER ADVISORY FROM 3 AM TO 3 PM PST THURSDAY FOR
WAZ520.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
97/99/The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2015Every state in 2015This day in weather historyWarnings in Oregon, 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: 604254.