Very strong winds aloft mixed down sporadically to the surface, primarily off the higher terrain west of the Tri-Cities despite strong warm air advection limiting vertical transport of higher momentum air. Isolated wind gusts in excess of 50 knots (58 mph) were reported in the Richland, Benton City, and Kahlotus area.
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 winds aloft mixed down sporadically to the surface, primarily off the higher terrain west of the Tri-Cities despite strong warm air advection limiting vertical transport of higher momentum air. Isolated wind gusts in excess of 50 knots (58 mph) were reported in the Richland, Benton City, and Kahlotus area.
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 29, 8:55 AM PST, 4 hours 5 minutes earlier.
Area Forecast Discussion...Updated National Weather Service Pendleton OR 855 AM PST Sat Dec 29 2018 Updated aviation discussion .UPDATE...A shortwave trough will drive a cold front across the region this evening/tonight. A mild day is expected today ahead of the front with increasing southerly winds. As the front moves through this evening precipitation will increase especially over the mountains and snow levels will lower. Winds may also push advisory levels in the lower basins. Post frontal upslope looks to be fairly significant for the northern Blue Mountains into Sunday so several inches of snow will be possible. Will evaluate the need for wind and snow highlights for the afternoon package. 78 && .AVIATION...12Z TAFS...VFR conditions will prevail through the period. However, precipitation along an advancing cold front late this afternoon and evening may briefly drop visibilities to MVFR. Winds will increase to 15-25 kts with higher gusts late this afternoon and through the evening. Pressure gradients behind an exiting cold front should weaken late tonight with wind speeds generally decreasing to less than 10-15 kts by sunrise. Earle && .PREV DISCUSSION... /issued 241 AM PST Sat Dec 29 2018/ SHORT TERM...Today through Monday night...Strong warm air advection over the region that brought widespread rain and snow to the region overnight will slowly weaken through late morning as very strong winds aloft (H850 50-60KTs) begin to turn westerly. It will be a very windy day for exposed ridgetops in our Washington and northern tier of Oregon Counties today, but do not see much support for enough momentum transport to the surface to support more than 20 to 30 mph winds through the afternoon for the lower elevations. A cold front will sweep across the area this evening bringing another round of precipitation primarily to the Cascades and Blues this afternoon and evening. Snow levels will initially be well above pass elevation, falling quickly with the onset of heavy precipitation in the Washington Cascades. Think a bulk of the precip falls prior to the snow levels coming down so do not anticipate issuing any winter hazards at this point. A similar scenario will play out in the northern Blues with a bulk of the heaviest precipitation falling while snow levels are still above 5000 feet, but lingering upslope as the front weakens across Oregon will keep snow showers going through midday Sunday with 2 to 5 inches of accumulation possible. Winds will increase along the front as cold air advection enhanced momentum transport to the surface and may see some 25 to 35 mph winds with higher gusts for a couple hours near midnight, especially across northern Franklin County. Given limited areal and temporal nature of the threat will not issue any wind highlights at this time. Breezy winds will continue into Sunday morning and slowly taper off through the day. Ridging builds into Monday with all precipitation coming to an end. Will be quite chilly Monday and especially Monday night with lows for much of the Basin in the low to mid 20s. With all the recent precipitation and high pressure overhead will likely start to see the signs of Basin fog returning by Tuesday morning. Peck LONG TERM....(Tuesday through Friday) Pleasant weather conditions are on tap as we kick off the New Year. In the wake of an early week storm system, northern Pacific high pressure looks to build in across the Pacific Northwest, yielding rather mild and dry conditions for January. Temperatures to start off near normal Tuesday, generally in the mid 30s to near 40 in the Columbia Basin and mid 20s to mid 30s in the highlands and mountains. However, as winds become south/southwest with building high pressure, we should see our daily highs rise by some 10 degrees, nearing the lower 50s for some lower elevation locations by the end of the week. Windy conditions may develop late in the week as low pressure intensifies over the Columbia Basin, especially for the Grande Ronde Valley and perhaps the foothills of the Blue Mountains. Much of the period looks to remain dry outside of a few mountain snow showers, though models are somewhat consistent in showing another upper storm system affecting the region Thursday into Friday. At this time, the greater rain/snow chances look to remain over the Cascades and points west, with lesser chances over the Columbia Basin and adjacent Blue Mountains. Given the rather mild weather, anything that falls in the lower elevations will likely be liquid, with snow confined to mountains and elevations above 4000 ft. && .PRELIMINARY POINT TEMPS/POPS... PDT 52 37 43 24 / 10 50 30 20 ALW 54 38 44 26 / 20 60 40 10 PSC 52 38 47 27 / 10 10 10 10 YKM 47 32 44 24 / 20 40 0 0 HRI 52 38 47 26 / 10 20 20 10 ELN 44 33 40 21 / 40 60 10 0 RDM 48 32 39 22 / 10 30 40 20 LGD 40 33 37 19 / 60 90 70 40 GCD 43 33 35 18 / 20 60 60 40 DLS 49 38 46 29 / 50 60 20 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && 78
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
756 AM PST SAT DEC 29 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0753 AM SLEET 5 NNE LA GRANDE 45.39N 118.07W
12/29/2018 M4.00 INCH UNION OR TRAINED SPOTTER
SPOTTER MEASURED 4 INCHES OF SNOW ACCUMULATION IN 12
HOURS.
&&
RQBPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1041 AM PST SAT DEC 29 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0956 AM NON-TSTM WND GST 13 WNW BICKLETON 46.08N 120.54W
12/29/2018 M58 MPH YAKIMA WA MESONET
THE HIGH RIDGE RAWS MESURED A WIND GUST OF 58 MPH.
ELEVATION 2106 FEET.
&&
RQBThe 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 Washington in 2018Every state in 2018This day in weather historyWarnings in Washington, December 2018
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: 793968.