Localized but very intense wind gusts occurred in and near the foothills of Boulder and Larimer counties. Peak wind gusts included 85 mph near Gold Hill and 79 mph just west of Loveland.
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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 BOU wrote it up.
Localized but very intense wind gusts occurred in and near the foothills of Boulder and Larimer counties. Peak wind gusts included 85 mph near Gold Hill and 79 mph just west of Loveland.
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 Apr 10, 8:49 PM MST, 3 hours 3 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 949 PM MDT Tue Apr 10 2018 .UPDATE... Issued at 944 PM MDT Tue Apr 10 2018 No real big changes needed in the short term besides to increase cloud cover tonight due to the mid and high level wave clouds pushing across the state. Looked into the 00z NAM and GFS runs in regards to tomorrow's and Thursday's Red Flag Warnings, and nothing is really compelling me to make any changes at this point. Thursday's warnings may need to be expanded into Weld County and possibly eastern Larimer, but that is still too far away to make a call at this point. && .SHORT TERM...(This evening through Wednesday) Issued at 133 PM MDT Tue Apr 10 2018 An upper level ridge centered over the Central Rockies will flatten and shift east of the area tonight. Westerly flow aloft will replace the ridge and increase through the day Wednesday. There may be enough moisture in the westerly flow aloft to produce a few light snow showers over the far northern mountains Wednesday morning. This moisture is expected to produce mostly cloudy skies elsewhere tonight and early Wednesday. Overnight lows will be mild, because of the mostly cloudy skies and warm airmass over the area. A surface low moves across Wyoming late tonight and Wednesday. This will produce gusty west winds. The winds increase and become gusty by late morning. Models indicate 30-35 knot winds mix down, so gusts to 40 mph look like a good bet from late morning through mid afternoon. The surface low shifts farther east, and a new surface trough forms over eastern Colorado. This is expected to cause winds to slowly decrease during the late afternoon hours. In addition to the gusty winds, low relative humidities will result in critical fire weather conditions. High temperatures will be warm Wednesday due the warm airmass and downslope winds. Temperatures are expected to reach the upper 70s to lower 80s. Record high for Denver is 80 degrees Wednesday and could be tied or broken. .LONG TERM...(Wednesday night through Tuesday) Issued at 133 PM MDT Tue Apr 10 2018 ...Above average temperatures combined with gusty winds through Thursday will bring extreme fire danger for Eastern Colorado... Wednesday night into Thursday an upper level disturbance will continue to bring strong WSW flow over the state. At the surface both the GFS and NAM show a deepening lee side low that will help to sustain downsloping winds off the foothills. Models show very little RH recovery overnight given the continued wind patterns and sfc low. For Thursday the upper trough that was in place over the western coast will move into the Great Basin region early Thursday. Flow aloft will strengthen ahead of the main energy as it enters SW Colorado. At the surface a surface low will deepen creating extreme fire weather conditions. Areas to the NE near the NE border could be slightly cooler depending on where the surface low sets up, however the areas sough of and along I-70 extending to the east and into southern Colorado will see warm dry conditions through Thursday with the increased, warm SW flow. High temperatures for Thursday will reflect this will areas on the plains seeing highs in the mid to upper 70s. More specific details regarding fire weather highlights can be found in the fire weather section. Lift ahead of the trough will increase by late morning hours in the high country. Model cross sections show increasing mid-level moisture by Thursday afternoon over the divide with showers and isolated thunderstorms beginning by the evening hours and changing over to snow during the overnight hours. At this time we are only expecting light to moderate snow accumulations of 3 to 6 inches with the possibility of up to 8 inches over the higher terrain by early Friday. For Friday the models seems to be in decent agreement with the placement of the elongated trough with the closed low to the North over Wyoming. Moisture on cross sections will continue to increase and deepen through Friday morning and extend onto the plains with the eastward progression of the surface low. Models show the upper low pressure system move into portions of eastern Colorado through the day Friday bringing with it increase northerly winds and colder temperatures. Continue to agree with previous forecast in regards to the placement of the higher pops on the plains out to the east. The urban corridor will be on the edge of the higher precipitation but still windy and cold with wind chill readings dropping through the day. Main concerns for Friday revolve around model consistency over the next few days with the placement of the synoptic features. In addition, some models are indicating high winds on the plains with the southern push of the surface front that could bring blowing snow/possible blizzard conditions on the plains for Friday afternoon or a high wind highlight over the foothills and Denver areas. Will continue to monitor this system over the next few shifts. Temperatures will take a sharp dip on Friday with this system with highs only reaching into the upper 40s on the plains and dropping into the 20s by the overnight hours. By the weekend some light snow will be possible overnight into Saturday with the wrap-around from the exiting low over KS and NE. Behind it a gradual warming trend with drying conditions through Monday before another shot on Tuesday. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 944 PM MDT Tue Apr 10 2018 VFR conditions will persist through Wednesday with high clouds streaming over the area. Winds currently will be settling into the south-southwest drainage directions by 06z. Next aviation weather issue comes late Wednesday morning and into the afternoon with gusty west winds to 30-35 knots, developing around 16-17Z Wednesday. && .FIRE WEATHER... Issued at 133 PM MDT Tue Apr 10 2018 West winds will increase Wednesday morning with gusts to 30 to 40 mph by late morning. The gusty west winds will continue through mid afternoon and then slowly decrease through late afternoon and early evening. Relative humidity values fall into the lower teens and upper single digits during the afternoon hours resulting in critical fire danger for Wednesday. On Thursday, fire danger will be critical. Extreme conditions will develop from Park county and the Southern Foothills across the Palmer Divide area and over the eastern plains. A Red Flag Warning for Thursday will continue from 10 am until 9 pm for gusty winds of 30 to 40 mph with RH levels reaching into the low teens. && .BOU WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 11 AM to 7 PM MDT Wednesday for COZ214>216- 238>251. Red Flag Warning from 10 AM to 9 PM MDT Thursday for COZ214-216- 239>241-245>247-249. && UPDATE...Kriederman SHORT TERM...Meier LONG TERM...Bowen AVIATION...Kriederman FIRE WEATHER...Meier/Bowen
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1051 AM MDT Tue Apr 10 2018 COZ030>051-111700- 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- 1051 AM MDT Tue Apr 10 2018 ...RED FLAG WARNING IN EFFECT 11 AM TO 7 PM MDT WEDNESDAY FOR THE FRONT RANGE FOOTHILLS...SOUTH PARK...AND ALL OF THE PLAINS... ...RED FLAG WARNING IN EFFECT FROM 10 AM TO 9 PM MDT THURSDAY FOR SOUTH PARK...SOUTHERN FRONT RANGE FOOTHILLS...PALMER DIVIDE...AND NEARBY ADJACENT PLAINS TO DENVER AND AKRON... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Mild and dry conditions will prevail today. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Fire danger will increase to critical on Wednesday with extreme conditions on Thursday. This is due to above normal temperatures, gusty winds, and low humidity levels. Extreme fire danger will likely develop over South Park, the Southern Foothills, Palmer Divide, and adjacent plains by Thursday afternoon as winds continue to strengthen with gusts between 40 and 50 mph possible. The next storm system will move across the state Thursday night into Friday, bringing a return of rain and snow showers to the mountains, and a chance of snow and colder temperatures over the plains. Light to moderate accumulations can be expected in the mountains, with little if any accumulation across the plains. It will remain windy through Saturday before finally subsiding for Sunday and Monday. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2018Every state in 2018This day in weather historyWarnings in Colorado, April 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: 746266, 746269.