A strong cold front brought strong winds to parts of northeast California.
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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.
A strong cold front brought strong winds to parts of northeast California.
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 19, 4:17 PM PST, 47 minutes earlier.
Area Forecast Discussion
National Weather Service Medford OR
417 PM PST Tue Dec 19 2017
.SHORT TERM...Today through Thursday...
To see a graphic of our detailed hazards, to include winter storm
warnings and winter weather advisories, please go to
www.wrh.noaa.gov/map/?wfo=mfr
The much anticipated strong front has come in a bit faster than
the consensus of the model guidance had suggested. However, winter
weather headlines for the lower elevations have been adjusted to
begin later in many areas to be consistent with forecast elements.
Also all winter weather headlines have been extended to 10 AM PST
Wednesday morning due to expected lingering snowfall impacts
associated with potentially locally heavy snow showers in the
morning. Snow levels are currently between 4000 and 4500 feet
across much of the forecast area, and are on track to fall this
evening, to the 1500 to 2000 foot range overnight.
Other adjustments to the forecast today were to lower the bottom
elevation of the winter weather advisory for the west side
valleys in Jackson, Josephine, and Douglas Counties to 1500 feet.
This elevation is consistent with our snow accumulation graphic where
1 inch of snow or more is expected. In short, most of the
snowfall early this evening will be above 2500 foot elevations.
Late this evening, overnight, and into Wednesday morning
precipitation will become showery. Model guidance indicates a
secondary impulse associated with the upper level cold core
moving in from the north-northwest tonight nearly strong enough
to produce lightning across the interior west side. Thunder has
not been added inland, as the probability of this occuring is less
than 20 percent. There is, however, reasonable consensus amongst
the model guidance for a burst of snowfall in Jackson County
between 4 AM and 8 AM PST Wednesday, so this has been worded for
in the winter weather advisory product.
During the afternoon tomorrow we expect showers to continue with
low snow levels, but road temperatures will warm and snow shower
intensity and coverage will diminish with time from west to east.
Skies will then begin to clear tomorrow evening setting the stage
for a cold night and a solid freeze up of any remaining moisture
and snow accumulations on untreated roadways across the forecast
area. Adjusted temperatures downward some for some interior
valleys for Thursday afternoon, as well, due to inversion
conditions that are expected to redevelop. BTL
.LONG TERM...Friday, Dec 22nd through next Tuesday, Dec 26th.
Models start in very good agreement Friday, and over the east stay
in agreement through the end of the extended. However, once again
over the west the ensemble plots devolve into a mess that makes
van Gogh's "The Starry Night" look like a photograph of a night
sky.
Friday sees a weak front slip down the backside of the upper ridge,
with light precipitation possible in the northern portions of the
forecast area through Friday night.
The upper ridge moves over the region Saturday, with offshore flow
spreading across the east side by Saturday afternoon. This upper
ridge shifts east Sunday ahead of the next system that brings a warm
front through in the afternoon. This is when the models begin to
show increasingly varying paths with decreasing confidence as the
ensemble plots increasingly looking like a handful of spaghetti
thrown at the wall over the west. With this variations in the
operational models confidence decreases to low as we head into mid
week on timing, strength, precipitation amounts, etc... as we head
into mid week next week. Sven
&&
.AVIATION...19/12Z TAF CYCLE...A strong front is moving inland this
afternoon and will shift east of the Cascades in the evening. Ahead
of this front expect gusty winds to develop. A period of low level
wind shear is also expected, mainly in the Umpqua this afternoon.
Gusty winds are expected to develop in the Rogue Valley and east of
the Cascades, including at KMFR and KLMT, this afternoon into early
this evening.
Moderate precipitation is expected ahead of and with the frontal
passage from the Cascades west this afternoon into this evening with
light precipitation east of the Cascades. MVFR cigs are expected to
develop from the Cascades west this afternoon with MVFR cigs also
continuing along the coast along with local IFR. East of the
Cascades expect mainly VFR through late this afternoon. A cold and
showery air mass will move into the area behind the front this
evening and tonight. Snow levels will fall fairly quick, and this
will bring in more widespread MVFR/IFR cigs/vsbys in rain and snow
showers across the area this evening through Wednesday morning. Snow
levels are expected down to 1200 feet elevation tonight and
Wednesday morning. Mountain obscurations will become widespread
from the Cascades west this afternoon, then spread east of the
Cascades this evening and tonight. Along the coast, expect
conditions to improve to VFR with areas of MVFR cigs/visibilities in
rain showers this evening through Wednesday morning. -CC
&&
.MARINE...Updated 200 PM PST Tuesday 19 Dec 2017...Gale force
southerly winds and very steep seas will continue over the coastal
waters this afternoon the as the front gradually inland. Winds will
shift to the west to northwest and decrease late this afternoon into
early this evening. Gusty west winds of around 20 to 30 kt are
expected this evening and tonight. Seas will remain high and very
steep due to a combination of short period wind seas and increasing
west to northwest swell. Winds will gradually lower on Wednesday.
Seas are expected to remain very steep and hazardous Wednesday
morning through Wednesday evening, with seas dominated by a 13 to 14
ft west swell at 11 seconds. Seas will gradually subside and winds
will turn northerly Wednesday night. These winds will persist into
the weekend with gradually subsiding seas. Another front will
approach the area Sunday night into Monday and expect increasing
seas as southwest and west swell builds into the area. -CC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 10 AM PST Wednesday for
ORZ029>031.
Wind Advisory until 4 AM PST Wednesday for ORZ030-031.
Winter Storm Warning until 10 AM PST Wednesday for ORZ029-030.
High Wind Warning until 4 AM PST Wednesday for ORZ031.
Winter Storm Warning until 10 AM PST Wednesday for ORZ027-028.
High Wind Warning until 4 PM PST this afternoon for ORZ021-022.
Winter Weather Advisory from 7 PM this evening to 10 AM PST
Wednesday for ORZ023>026.
Winter Storm Warning until 10 AM PST Wednesday for
ORZ023-025-026.
Winter Weather Advisory from 7 PM this evening to 7 AM PST
Wednesday for ORZ021-022.
Winter Weather Advisory until 10 AM PST Wednesday for
ORZ027-028.
CA...Winter Weather Advisory until 10 AM PST Wednesday for
CAZ084-085.
Winter Weather Advisory from 7 PM this evening to 10 AM PST
Wednesday for CAZ080>083.
Winter Storm Warning until 10 AM PST Wednesday for CAZ080.
Pacific Coastal Waters...Small Craft Advisory until 4 PM PST this afternoon for
PZZ356-376.
Gale Warning until 4 PM PST this afternoon for
PZZ350-356-370-376.
Hazardous Seas Warning until 10 PM PST Wednesday for
PZZ350-356-370-376.
BTL/SBN/CCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
327 PM PST TUE DEC 19 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0326 PM HEAVY RAIN 2 SSW OBRIEN 42.05N 123.71W
12/19/2017 M1.00 INCH JOSEPHINE OR TRAINED SPOTTER
1 INCH SINCE 10AM.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
328 PM PST TUE DEC 19 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0300 PM HEAVY RAIN 2 WSW OBRIEN 42.06N 123.73W
12/19/2017 M0.80 INCH JOSEPHINE OR TRAINED SPOTTER
0.8 INCHES SINCE 10 AM PST. THE DURATION OF
THE HEAVY RAIN EVENT WAS 5 HOURS.
&&The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
The Timber Mountain RAWS recorded a gust to 61 mph at 19/1803 PST.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2017Every state in 2017This day in weather historyWarnings in California, December 2017
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: 725093.