Temperatures were above normal and precipitation was below normal across much of Colorado during the month of November. As a result, drought conditions persisted across the entirety of the western slope and worsened to the exceptional category in some areas by the end of the month.
Every event with a place to put it; 21 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 GJT wrote it up.
Temperatures were above normal and precipitation was below normal across much of Colorado during the month of November. As a result, drought conditions persisted across the entirety of the western slope and worsened to the exceptional category in some areas by the end of the month.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Oct 31, 10:27 PM MST, 1 hour 33 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 1127 PM MDT Sat Oct 31 2020 .SHORT TERM...(Tonight through Sunday night) Issued at 144 PM MDT Sat Oct 31 2020 The large scale synopic pattern shows an upper level trough moving east over the Plains late today while an upper level ridge sits over the West Coast, and a weak cut-off upper level low is south of the bight of Southern California. Dry northwest flow aloft and light valley winds will continue through tonight. During the day Sunday, the upper level ridge suppressed across far southern TX and the Gulf of Mexico will build northwest between the digging trough over the eastern U.S. and the cut-off low off Southern California. What you see/saw today is what you'll see Sunday with a couple of degrees of warming. .LONG TERM...(Monday through Saturday) Issued at 144 PM MDT Sat Oct 31 2020 More of the same can be expected Monday with the exception of some higher clouds scooting over the Four Corners region as upper level moisture feeds north between the cut-off low over Southern California and the ridge over our area. Forecasting the eastward progress of cut-off lows is always tricky, but all models are in agreement with the low opening up and moving over our region Tuesday and Tuesday night. Low levels remain dry and the trough is already going to struggle to bring any deeper moisture. So the chance of precipitation with its passage is very low, with the best chances over the mountains of southeast UT and southwest CO. Model ensembles agree on an upper level ridge and above normal heights over the region Wed through Thurs, then decreasing heights and increasing southwesterly flow aloft Friday and Saturday ahead of an anomalously cold upper level trough digging southeastward over the western U.S. There are still differences in the handling of embedded shortwaves and speed of moisture increase over eastern UT and western CO as we go through the weekend. The main story is high confidence in dry and above normal temperatures through Friday...with lower valleys reaching the upper 60s to mid 70s and warmest days Wednesday through Friday. There is medium confidence in increasing clouds and chances for precipitation Saturday along with slightly cooler high temperatures. A return to below normal temperatures and unsettled conditions with periods of rain or snow appears likely from late in the weekend into early the following week with the deep trough over the region. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 1127 PM MDT Sat Oct 31 2020 Expect clear skies, light wind and VFR conditions through the next 24 hours. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...BM LONG TERM...BM AVIATION...NL
Hazardous Weather Outlook National Weather Service Grand Junction CO 330 AM MDT Sat Oct 31 2020 COZ001>014-017>023-UTZ022>025-027>029-010930- Lower Yampa River Basin-Central Yampa River Basin- Roan and Tavaputs Plateaus-Elkhead and Park Mountains- Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor- Central Colorado River Basin-Grand and Battlement Mesas- Gore and Elk Mountains/Central Mountain Valleys- Central Gunnison and Uncompahgre River Basin- West Elk and Sawatch Mountains-Flat Tops- Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide- Northwest San Juan Mountains-Southwest San Juan Mountains- Paradox Valley/Lower Dolores River- Four Corners/Upper Dolores River-Animas River Basin- San Juan River Basin-Southeast Utah-Eastern Uinta Mountains- Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat- La Sal and Abajo Mountains-Canyonlands/Natural Bridges- 330 AM MDT Sat Oct 31 2020 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Sunday through Friday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
21 drought. Local standard time, as filed.
The extreme (D3) drought persisted across the eastern and central portions of the zone through the end of November while the exceptional (D4) drought in the western portion of the zone expanded slightly further south.
The exceptional (D4) drought continued to expand to include all but the far northeast and southeast portions of the zone by the end of November.
Extreme (D3) drought conditions persisted across the eastern half of the zone while the exceptional (D4) category remained over the western half of the zone by the end of November.
The exceptional (D4) drought persisted across the entirety of the zone through the end of November.
The exceptional (D4) drought over the far eastern portion of the zone expanded to include the entirety of the forecast zone by the end of November.
The extreme (D3) drought persisted across the far eastern portion of the zone through the end of November while the exceptional (D4) category continued across the remainder of the zone.
The extreme (D3) drought persisted across the northwest portion of the zone through the end of November while the exceptional (D4) category continued across the remainder of the zone.
The exceptional (D4) drought persisted across all but the far western portion of the zone through the end of November.
The exceptional (D4) drought continued to expand to include the far southern portion of the zone with only the far northwest portion of the zone remaining in the extreme (D3) category by the end of November.
The extreme (D3) drought persisted across the entirety of the zone through the end of November.
The extreme (D3) drought persisted across the majority of the zone through the end of November while the exceptional (D4) category continued across the far southeast portion of the zone.
The exceptional (D4) category persisted across all but the far southwest portion of the zone through the end of November.
The extreme (D3) drought persisted across all but the far northern portion of the zone through the end of November where exceptional (D4) conditions continued.
The exceptional (D4) drought persisted across the western and central portions of the zone while extreme (D3) conditions continued elsewhere through the end of November.
The extreme (D3) drought persisted across the western portion of the zone through the end of November while exceptional (D4) conditions continued over the eastern portion of the zone.
The exceptional (D4) drought persisted across the entirety of the zone through the end of November.
The exceptional (D4) drought continued across much of the northern and southern tiers of the zone through the end of November with extreme (D3) conditions persisting elsewhere in the central areas.
The extreme (D3) drought persisted across the majority of the zone through the end of November with the exceptional (D4) category continuing across the far northeast and southern portions of the zone.
The exceptional (D4) drought continued across all but the far southeast and far southwest portions of the zone through the end of November where the extreme (D3) category persisted.
The extreme (D3) drought persisted across all but the north-central portion of the zone through the end of November where the exceptional (D4) category continued.
The exceptional (D4) drought continued across all but the far northeast portion of the zone through the end of November where extreme (D3) conditions persisted.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2020Every state in 2020This day in weather historyWarnings in Colorado, November 2020
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: 923308, 923449, 923450, 923451, 923452, 923453, 923454, 923455, 923456, 923457, 923458, 923459, 923460, 923461, 923462, 923463, 923464, 923465, 923466, 923467, 923468.