A low pressure system situated off the coast of Oregon spread moisture into parts of Southeast Oregon and Southwest Idaho with areas of heavy snow.
Every event with a place to put it; 3 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 BOI wrote it up.
A low pressure system situated off the coast of Oregon spread moisture into parts of Southeast Oregon and Southwest Idaho with areas of heavy snow.
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 Boise, ID wrote its last area forecast discussion before the first event at Nov 30, 8:07 PM PST, 4 hours 53 minutes earlier.
Area Forecast Discussion
National Weather Service Boise ID
907 PM MST Sat Nov 30 2019
.DISCUSSION...The next strong winter system continues to approach
the forecast area, with radar beginning to show some returns in
southeastern Oregon. As the system approaches overnight,
conditions will begin to deteriorate from west to east, with the
strongest impacts expected across eastern Oregon, especially
around Burns, Ontario, and over portions of Baker County in Oregon.
Snowfall will spread into southwestern Idaho overnight. Roadway
impacts are anticipated with this system, with another instance of
hazardous travel for holiday travelers, especially on Sunday.
Winter weather highlights remain for eastern Oregon into the
Treasure Valley of Idaho, and into the Owyhee Mountains through
Sunday evening. Periods of gusty to breezy wind may accompany the
system as it moves through, with south to southeast wind
increasing through the morning hours. Periods of snowfall may
last into Monday before weakening, especially for southwestern
Idaho. Current forecast remains on track, and will continue to be
monitored for any product adjustments as the system moves further
into the area.
&&
.AVIATION...Anticipate snow to increase over SE Oregon by 01/09Z,
and into SW Idaho by 01/14Z...resulting in VFR through 01/09Z, then
areas of MVFR/IFR and localized LIFR/VLIFR in vis/ceilings.
Mountains obscured. Surface winds: E to SE 5-15 kts tonight,
becoming 10-20 kts with gusts to 25 kts Sunday morning and
afternoon. KJER will be capable of wind gusts to 35 kts between
01/08Z-23Z. Winds aloft at 10Kft MSL: SW 25-40 kts.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Monday...A weak upper ridge and
accompanying dry conditions will shift east tonight as a low
pressure system off the coast spreads moisture into the region.
Southwest flow aloft will bring snow to eastern Oregon late
tonight and southwest Idaho Sunday morning. Highest snowfall
totals of 3 to 6 inches are expected in portions of southeast
Oregon, 2 to 4 inches in far western Idaho, and up to 2 inches for
the remainder of the area through Sunday evening. Winter Storm
Warnings and Advisories are in effect. Travel will be impacted,
especially in eastern Oregon Sunday morning. Moisture with
embedded disturbances within a southwest flow aloft will result in
a chance of precipitation Sunday night and Monday. Snow levels
will rise to above valley floors by Monday afternoon. Temperatures
will trend warmer, to near normal on Monday.
LONG TERM...Monday Night Through Thursday...Lingering showers
mainly in the north will end early Tuesday morning with snow
levels 4000 to 5000 feet. A brief dry period will last from Tue
afternoon through Wed morning as weak ridging moves in aloft. Flow
aloft will strengthen late Wed and small impulses embedded in
southwest the flow will bring increasing chances of precipitation
through Thursday. Snow levels will range from around 3500 to 4500
feet late Wed into Thursday. Temperatures will be close to normal
Tuesday through Thursday.
Thursday night through Saturday night...Showery and breezy are
the conditions expected as a strong, moist, and unstable low
pressure system nears the region. Look for snowfall along the
mountains and rain in the major valleys with a mix along the
foothills. Models are in agreement with the heaviest precipitation
occurring from late Friday night through Saturday afternoon as the
system moves through the region. However, initial wind shadowing
affects will help keep precipitation amounts lower in the
Treasure and Magic Valleys until Saturday. Precipitation amounts
are expected to gradually diminish as the low pressure system
starts its exit eastward. Highs are expected to measure in around
3 to 5 degrees above normal while overnight lows drop down to
around 2 degrees below normal.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory from 5 AM to 11 PM MST Sunday
IDZ012-014-029-033.
OR...Winter Storm Warning from 2 AM MST /1 AM PST/ to 11 PM MST /10
PM PST/ Sunday ORZ061>064.
&&
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DISCUSSION...KB
AVIATION.....SH
PREV SHORT TERM...BW
PREV LONG TERM....SP/WHThe national radar mosaic for the moment the first event began.
3 heavy snow. Local standard time, as filed.
Trained spotters reported 6 to 9 inches of new snow across Harney County.
The COOP observer in Halfway reported 6 inches of new snow and a trained spotter at Huntington reported 9 inches.
The COOP observer at Ontario reported 5 inches of new snow and trained spotters reported from 4 to 7 inches across Malheur County.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2019Every state in 2019This day in weather historyWarnings in Oregon, December 2019
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: 870296, 870295, 870297.