Strong winds developed over the Palmer Divide. Peak wind gusts included 66 and 61 mph near Monument.
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 BOU wrote it up.
Strong winds developed over the Palmer Divide. Peak wind gusts included 66 and 61 mph near Monument.
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 4, 9:50 AM MST, 1 hour 20 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 1050 AM MDT Sat Nov 4 2017 .UPDATE... Issued at 1050 AM MDT Sat Nov 4 2017 Gusty west to southwest winds are spreading east across eastern Colorado. The winds are mixing warm air aloft down and temperatures are jumping up quickly with the increase in wind. Highs in the upper 60s to mid 70s appear likely across the area today. The far northeast corner could remain cooler if the colder air is unable to be scoured our. In regards to the High Wind Warning, not seeing the strong winds north of the Palmer Divide. In the Colorado Springs area gusts to around 60 mph have been report. North of the Palmer Divide, winds are only gusting to around 45 mph. If winds don't increase this morning, may cancel the High Wind Warning around noon. Snow has moved into the mountains this morning. The Pacific airmass is warm which has kept most roads just wet. However, slick and snow covered roads have been observed at times over the higher passes where it is colder. Expect conditions to deteriorate later today and especially tonight over the northern mountains when the snow increases and temperatures fall. && .SHORT TERM...(Today and tonight) Issued at 440 AM MDT Sat Nov 4 2017 An active day in store, on two fronts. Strong southwest flow aloft across the state is going to bring warmer temperatures across the forecast area, but with blustery southwest winds. Winds are expected to be strongest over the Palmer Divide, where the higher elevations will make it easier for the strong winds aloft to mix to the surface. Model cross sections show 50 to 60 knot winds at 10,000 feet MSL this morning which will likely mix to the surface by midday. Sustained winds around 40 mph and gusts in excess of 60 mph will be possible. A High Wind Warning will be in effect for zone 41 through 3 PM this afternoon. Elsewhere across northeast Colorado, temperatures are expected to climb into the lower 70s, but with southwest winds of 15 to 25 mph by afternoon. Areas along the Front Range foothills may see some higher gusts at times. The other weather maker today will be increasing moisture over the northern mountains that begins producing rain and snow by afternoon. Snow levels will initially be quite high, above 10,000 feet, but they are expected to come down tonight as an upper level weather disturbance embedded in the west-southwest flow crosses over the state. Satellite imagery shows the moisture with tonight's weather system moving over southern Idaho and Utah this morning. The period of heaviest precipitation is forecast to be tonight as the strongest dynamic forcing moves over the state. Orographic effects will also be present with low and mid level winds in the 30 to 40 knot range. An upper level jet in place over the will also help things out. The northern mountain zones could pick up 5 to 10 inches of snow overnight, with additional snow after that. A Winter Storm Warning for zones 31 and 33 will go into effect at 6 PM MDT. One other thing to keep an eye on later tonight will be a cold front moving into the northeast corner of the state overnight. At this time it looks like the surface feature will be dry enough that only a wind shift is observed. More effects from the front will be felt on Sunday when temperatures are some 20 degrees cooler than this afternoon. .LONG TERM...(Sunday through Friday) Issued at 440 AM MDT Sat Nov 4 2017 WSW flow aloft will remain across the area Sun thru Sun night as an upper level trough moves into the NWRN US. Cross-sections continue to show quite a bit of moisture embedded in the flow with lapse rates around 7 c/km. In addition position of upper level jet will likely lead to some banded heavier pcpn in the mtns areas of Jackson and Larimer counties favored by WSW flow. Further southward expect pcpn amounts will gradually decrease along with overall coverage. Over nern CO a cold front will affect the plains as a sfc low resides over sern CO. With position of upper level jet and some enhanced low lvl upslope closer to the WY border, there will be a good chc of pcpn fm the nrn Foothills across the adjacent plains mainly north of a Fort Collins to Greeley line in the morning hours. Temps will be cold enough for a mix of rain and snow in the Foothills with some accumulation possible abv 7500 ft. Over the rest of the plains it will be mainly dry. Aftn highs will range fm the lower to mid 40s nr the WY-NE border with lower 50s elsewhere except over srn Lincoln county where readings may reach the lower 60s. For Sun Night the ECMWF still shows a possible disturbance moving across nrn CO. Thus snow will continue in the mtns mainly across Jackson and Larimer counties. Over nern CO there will be another chc of pcpn especially nr the WY-NE border as the disturbance moves across in the evening hours. On Mon the upper level trough over the NWRN US will begin to shift east. This will leave WSW flow aloft across the area. Cross-sections show a decrease in moisture in the mtns so additional accumulations thru the aftn look rather light at this point. Across nern CO sfc low pres will develop nr the Foothills with sely low lvl flow over the plains. Overall this would probably lead to a Denver Cyclone by aftn with the potential for widespread low clouds across much of the plains except over the Palmer Divide where downslope flow would be in place. As a result this will likely lead to issues with aftn highs. For now will keep highs in the mid 40s to lower 50s across much of nern CO but it could end up being cooler. For Mon night into Tue the models have trended towards the ECMWF solution with an upper level ridge forming over the NWRN US which allows for the upper level trough to shift southeast across the area. The ECMWF is slower and stronger with the upper level trough while the GFS is faster and not as stg. Furthermore both models show a cold fnt moving across nern CO Mon night with upslope flow into Tue. Meanwhile, as the upper level trough moves across, there will be some weak to moderate qg ascent especially on Tue so will see a good chc of snow in the mtns and possibly across the plains as well. At this time snow amounts look on the light side. Highs on Tue across nern Co will only be in the 30s. For Tue night into early Wed the main upper level trough will move across the area. Once again the ECMWF is stronger and slower with this feature versus the GFS. As a result, the ECMWF continues to have a good chc of pcpn over much of the area Tue night into early Wed while the GFS ends the pcpn by Tue evening. At this point with still a lot of uncertainty will keep in a chc of pcpn thru Tue night. By Wed aftn, even if the slower ECMWF is correct, pcpn should end by Wed morning with dry conditions by aftn. As for highs will keep readings in the upper 40s to lower 50s across nern CO. For Thu a flat upper level ridge will build into the area with dry conditions and warmer temperatures. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 1050 AM MDT Sat Nov 4 2017 Winds will be the primary aviation impact today. Winds will be west to southwesterly through the day with gusts of 25 to 35 knots through 00Z. Winds will be strongest around KAPA. Lows clouds are expected to move into the Denver area around 12Z Sunday morning behind a cold front. Ceilings are expected to fall below 1000 feet. There is a slight chance visibility could fall below a mile with the low clouds. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 6 PM MDT this evening to 5 AM MST Monday for COZ031-033. High Wind Warning until 3 PM MDT this afternoon for COZ041. && UPDATE...Meier SHORT TERM...Dankers LONG TERM...RPK AVIATION...Meier
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1023 AM MDT Sat Nov 4 2017 COZ030>051-051630- 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- 1023 AM MDT Sat Nov 4 2017 ...High Wind Warning for the Palmer Divide through 3 pm this afternoon... ...Winter Storm Warning Tonight through Sunday Night in the northern Mountains... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Very warm and breezy conditions are expected today across the northeast plains as strong southwesterly flow aloft covers Colorado. The combination of warm temperatures and gusty winds will elevate fire danger levels across the plains. Winds are expected to be strongest over the Palmer Divide. Winds of 35 to 45 MPH with gusts of 60 to 70 MPH may cause travel problems due to strong crosswinds and low visibilities in blowing dust. The strong winds may also knock over some trees and branches. Winds are expected to decrease late in the afternoon. In the mountains, light snow and icy roads will can be expected over the higher mountain passes this afternoon, with mild and windy conditions below 10 thousand feet. Tonight, temperatures will cool with lowering snow levels. Snow will be heavy at times over the Rabbit Ears and Gore Ranges. Heavy snow will also be possible in the mountains of Grand and Larimer Counties. Five to 10 inches of snow will be possible over the northern mountains. Less snow is expected over the mountains of Summit County with 3 to 6 inches of snow possible. .DAYS TWO THROUGH SEVEN...Sunday through Friday Periods of moderate to heavy snow will continue in the higher mountains through Sunday night and then begin to decrease on Monday. The heaviest snowfall will be north of Interstate 70, along west and southwest facing slopes. Storm totals by late Sunday night of 8 to 16 inches with locally up to 24 inches inches will be possible. There may be some rain mixed with snow showers in the mountain valleys as well with light snow accumulations. For Monday night through Tuesday another weather system will bring another good chance of snow to the mountains. There will also be a good chance of showers on the plains which will turn to snow late Monday night into Tuesday. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
1210 PM MDT SAT NOV 4 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1154 AM NON-TSTM WND GST 5 W ELBERT 39.22N 104.63W
11/04/2017 M61 MPH ELBERT CO AWOS
AWOS STATION MNH, 5 W ELBERT.
&&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 Colorado in 2017Every state in 2017This day in weather historyWarnings in Colorado, November 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: 726014.