Heavy snow developed in and near the foothills of Boulder and northern Jefferson counties, where storm totals ranged from 6 to 12 inches of snowfall. Periods of light to moderate snowfall occurred over the rest of the mountains and foothills, Palmer Divide, most of the urban corridor, and adjacent plains.
Every event with a place to put it; 9 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 BOU wrote it up.
Heavy snow developed in and near the foothills of Boulder and northern Jefferson counties, where storm totals ranged from 6 to 12 inches of snowfall. Periods of light to moderate snowfall occurred over the rest of the mountains and foothills, Palmer Divide, most of the urban corridor, and adjacent plains.
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 Denver/Boulder, CO wrote its last area forecast discussion before the first event at Nov 17, 4:03 AM MST, 57 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 403 AM MST Thu Nov 17 2022 .SHORT TERM...(Today and tonight) Issued at 400 AM MST Thu Nov 17 2022 ...WINTER RETURNS IN FULL FORCE... Surface analysis shows the leading edge of arctic air pushing across the northern plains in these early morning hours, and that will overtake the rest of the plains by/shortly after daybreak. Temperatures were in the lower to mid 20s behind the front, and that's about all we'll do today for highs as constant cold advection occurs throughout the day. In fact, by about 5 pm most locations should have dropped into the upper teens. Lows tonight will drop into the single digits, with below zero readings in the mountains and foothills. Now for the snow and travel impacts... Current observations show light snow and flurries falling over eastern Wyoming behind the arctic front. We'll see the same situation across our plains and foothills this morning with enough low level moisture, upslope, and weak dynamics. While most of this will remain on the light side, a couple briefly moderate bands will be possible as mid level frontogenesis begins to strengthen. The main threat for those bands would be over the northern tier of Colorado Counties where the Winter Weather Advisory starts early this morning. Denver will likely see some light snow as well for at least the latter half of the morning commute, but this snow should remain on the lighter side being farther away from the synoptic support and deeper moisture. The forecast for this afternoon is a little tricky, as most models show a little respite in the snow about mid day, before snow ticks up again late in the afternoon and evening. It's not uncommon to get a mid day lull in the lack of forcing, but again the northern border area remains under strong forcing and mid level frontogenesis. The passage of the upper jet max to our northeast means we'll also be getting into the right rear entrance region. Cross sections show persistent ageostrophic ascent associated with the F-gen, so we think at least the northern tier of counties will remain in healthier snowfall through the afternoon. It's not so clear cut in Denver with the possible diurnal wane, but with the improved forcing late this afternoon we would expect an increase in snowfall rates despite some of the latest mesoscale model data. This increase would occur by early evening at the latest, so we are still concerned with the evening commute across Denver. Travel conditions will be deteriorating so we'll continue to message that accordingly. One interesting note is if we see enough solar insolation we could actually get a little melting initially which would NOT be in our best interest for impacts. If that occurs and then we get a quick increase in snow in the evening commute it could be quite the difficult drive with a quick freeze/ice compaction. Current forecast road temps get us right up to the freezing mark around Denver, so it could be close. A better scenario would be for just light snow and roads to remain cold enough for a "middle of the winter" type snow covered road situation and limited ice formation. Otherwise, there's not much change in the overall guidance and expected storm total forecast. QPF numbers have shown their typical random gyrations, but overall SREF plumes remain constant with amounts around 0.20 inches liquid in Denver and around 0.35 inches closer to Boulder and Fort Collins. With favorable moisture and temperature profiles for dendritic crystal growth through a relatively deep layer, we're still looking for high SLRs close to 20:1 especially as we get into the deeper lift that slowly edges southward across the forecast area through tonight. We still expect locally heavy bands as well with the noted forcing mechanisms, and even hints of Conditional Symmetric Instability (CSI). Our forecast totals remain generally the same, with 2-6 inches across most of the I-25 Corridor, and 4-10 inches in/near the foothills with Boulder and Larimer Counties under the gun for the heavier totals. Lower amounts can be expected on the eastern plains with a dusting to 3 inches. Summit county remains on the edge of any orographic and dynamically forced precipitation through this evening. Not until overnight tonight will that area fill in entirely, so totals over most of this area will likely be on the low end of Advisory Criteria. Locations like Berthoud Pass and points north will have significantly more snowfall. Even the southern Front Range Foothills south of about Conifer and the Palmer Divide could be shorted on snow totals per some of the latest model guidance, but in these types of cases the best frontogentical band usually ends up slipping farther south than forecast so those areas should still receive a few inches of snow and have travel impacts that last through the Friday morning rush hour. All Winter Weather Advisories remain unchanged at this point. .LONG TERM...(Friday through Wednesday) Issued at 305 AM MST Thu Nov 17 2022 I did not make significant changes to the forecast in this package. Model solutions have been pretty consistent through the weekend and WPC cluster analysis of ensemble forecast systems suggests good confidence in these solutions through early next week. Around Tuesday, solutions start to diverge significantly. It still looks like the next chance of snowfall is Wednesday, but probably just light snowfall mostly confined to the high country. Friday morning, light snowfall will persist mainly in the southern mountains and foothills, Palmer Divide and adjacent plains including much of the urban corridor and specifically Denver metro area. There will likely be minor impacts to the morning rush hour, and our Winter Weather Advisory will remain in effect through 9 AM. As the trough axis moves overhead, synoptic ascent will turn to subsidence and gradual clearing will begin from north to south. Snowfall should diminish by noon. Total snow accumulations from this system will generally range from 2 to 6 inches across the I-25 Corridor, 4 to 10 inches in the mountains and foothills north of I-70 (favoring Boulder and Larimer Counties), and trace to 3 inches over the eastern plains. Skies should remain mostly cloudy through the day with fresh snow cover and light northerly cold air advection, which will keep temperatures very cold Friday. Expect highs in the 20s across the plains and mostly single digits and teens across the high country, which is 20 to 30 degrees below normal for most areas. Skies should then be mostly clear overnight, and low temperatures are forecast to fall into the single digits across the plains and negative single digits across the high country. It will likely become extremely cold in the typical cold pockets where strong inversions will form. Over the weekend, there will be a decreasing and more northerly flow aloft behind the trough. Under mostly clear skies, a warming trend will bring temperatures back to near-normal by Sunday, though they may remain a bit colder where snow cover remains and winds are lighter. Early next week, mostly clear and near-normal conditions should persist with a more zonal flow aloft. By Tuesday, model solutions start to diverge significantly so there is less confidence in forecast details through mid-week. However, no models show any strong, organized features approaching northeast Colorado, they instead disagree on the particulars of a rather disorganized synoptic pattern which doesn't look very threatening. We'll continue to carry slightly cool temperatures and a chance of light snowfall in the mountains on Wednesday. A stronger trough with proper placement could bring cooler conditions and maybe even some light snowfall to the lower elevations. A stronger ridge could mean mostly clear skies and near-normal temperatures persist through mid-week. It's too early to tell. && .AVIATION...(For the 12Z TAFS through 12Z Friday morning) Issued at 400 AM MST Thu Nov 17 2022 Arctic cold front should push through KDEN by 12Z-13Z, with lower MVFR clouds and visibility as light snow/flurries develop shortly behind it. Front will be about 30-60 minutes behind that at KBJC and KAPA, respectively. Could see some north/northeast gusts to around 25 knots with the frontal passage, before relaxing to around 10 knots through the rest of the period from the east/northeast. Snow intensity is expected to increase in the immediate Denver area TAF sites 22Z-01Z, with visibility dropping closer to 1SM and potential for locally heavier bands with lower visibility. Total snow accumulations by the time snow winds down early Friday morning are most likely to range between 2 and 5 inches at KDEN and KAPA, and 4 to 6 inches at KBJC. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 9 AM MST Friday for COZ031-033-035- 038-043. Winter Weather Advisory from noon today to 9 AM MST Friday for COZ034-036-039>041-045. && SHORT TERM...Barjenbruch LONG TERM...EJD AVIATION...Barjenbruch
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 409 AM MST Thu Nov 17 2022 COZ030>051-181115- Jackson County Below 9000 Feet- West Jackson and West Grand Counties Above 9000 Feet- Grand and Summit Counties Below 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- South and Southeast Grand/West Central and Southwest Boulder/ Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- Central and Southeast Park County- Larimer County Below 6000 Feet/Northwest Weld County- Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County- North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County- Elbert/Central and East Douglas Counties Above 6000 Feet- Northeast Weld County-Central and South Weld County-Morgan County- Central and East Adams and Arapahoe Counties- North and Northeast Elbert County Below 6000 Feet/North Lincoln County- Southeast Elbert County Below 6000 Feet/South Lincoln County- Logan County-Washington County-Sedgwick County-Phillips County- 409 AM MST Thu Nov 17 2022 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 9 AM MST FRIDAY FOR THE NORTHERN MOUNTAINS, FOOTHILLS, I-25 CORRIDOR, AND ADJACENT PLAINS... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Travel will be hazardous and slow due to developing slick and snowpacked roads. A few slick spots will be possible this morning, but the afternoon and evening commutes will be more heavily impacted. Hazardous travel conditions will persist overnight. Light snow and flurries will develop over most of the northern mountains, plains, and foothills this morning. Snow intensity will increase through the day across the northern tier of Colorado Counties, including locations like Estes Park, Fort Collins, and Greeley. This more persistent and heavier snow will then gradually shift southward across the forecast area late this afternoon through tonight. It will also be very cold as an arctic airmass overspread the region. Temperatures today will hold in the lower to mid 20s in most areas. Lows tonight will drop into the single digits, with some below zero readings in the mountains and foothills. Break out the winter parkas, mittens, and hats to protect yourself from the cold. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Friday morning, light snowfall will persist mainly in the southern mountains and foothills, Palmer Divide and adjacent plains including much of the urban corridor and specifically Denver metro area. There will likely be impacts to the morning rush hour. Total snow accumulations from this system will generally range from 2 to 6 inches across the I-25 Corridor, 4 to 10 inches in and near the mountains and foothills north of I-70 (favoring Boulder and Larimer Counties), and trace to 3 inches over the eastern plains. Very cold temperatures will persist Friday as well, with highs only in the 20s across the plains and single digits and teens in the high country, which is 20 to 30 degrees below normal in most areas. This system will clear out Friday and there will be a warming trend through the weekend. It still looks like the next chance of snowfall is Wednesday, but probably just light snowfall mostly confined to the high country. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight.
The national radar mosaic for the moment the first event began.
8 winter weather, 1 winter storm. Local standard time, as filed.
Storm totals ranged from 4 to 7 inches.
Storm totals ranged from 6 to 11 inches, except for 12.6 inches near Mount Audubon.
Storm totals ranged from 4 to 8 inches.
Storm totals ranged from 2 to 4 inches.
Storm totals up to 3 inches were observed west of Highway 85.
Storm totals ranged from 2 to 5 inches, and included 3.8 inches at Denver International Airport.
Storm totals ranged from 2 to 4 inches.
Storm totals ranged from 3 to 8 inches.
Storm totals included: 12 inches near Golden and west Boulder, 10.9 inches, 3.5 miles west-northwest of Arvada; 8 inches in Lakewood, 6 inches at Ken Caryl and Wheat Ridge, with 3 to 5 inches elsewhere.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2022Every state in 2022This day in weather historyWarnings in Colorado, November 2022
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 2026-10-01. Each event’s entry at NCEI: 1057936, 1057938, 1057939, 1057940, 1057941, 1057943, 1057944, 1057970, 1057972.