An ice storm began late Nov 9 and continued into Nov 10. It led to power outages and tree damage across 11 counties.
Every event with a place to put it; 16 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 OAX wrote it up.
An ice storm began late Nov 9 and continued into Nov 10. It led to power outages and tree damage across 11 counties. The maximum ice measurement was 1.06 inches. Counties in colder air received less and significantly more snow with a maximum of 10 inches record.
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 Omaha, NE wrote its last area forecast discussion before the first event at Nov 9, 5:49 PM CST, 2 hours 11 minutes earlier.
Area Forecast Discussion
National Weather Service Omaha/Valley NE
549 PM CST Mon Nov 9 2020
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 408 PM CST Mon Nov 9 2020
Forecast Summary:
Winter weather advisory has been issued for tonight through much of
Tuesday for snow in northeast Nebraska where up to 4 inches is
possible, and for ice accumulation of two-tenths from near
Interstate 80 and north and northwest. The rest of the forecast will
show continued cool temperatures averaging near or below normal
through the weekend. Light rain, or possibly a wintry mix, is
possible from Friday night through Saturday night.
Tonight and Tuesday:
Deep upper trough was swinging into the Rockies this afternoon, with
southwest flow aloft over our part of the world. Strong cold front
had plunged southeast today behind mid level system riding into the
Canadian Plains. Temperatures quickly dropped a good 20 degrees with
frontal passage across our CWA, from the 60s to the 40s, then
settled into the 30s an hour or two post frontal passage. Currently
only light showers were noted on area radars. However an increase in
precipitation areal extent and intensity is forecast overnight as
potent shortwave ejects into the Plains.
A classic overrunning situation has set up over our area with cold
surface air undercutting warmer air aloft. 850 flow is advertised to
remain generally southerly over the southern half of our CWA through
18Z, maintaining warm nose of above-freezing air above near-freezing
boundary layer. As forcing increases with approach of shortwave,
will see precipitation break out, likely after midnight, across most
of the CWA. Northwest of track, soundings cool toward all-snow in
northeast Nebraska after a brief period of potential freezing rain.
Snow there will be enhanced by comma head trowal configuration early
Tuesday leading to potential banded precip. Snow amounts up to 4
inches are likely there, though banding may enhance totals over
local areas.
Farther south including the Interstate 80 corridor, warm air aloft
will maintain rain profile through 18Z when cold air behind exiting
shortwave invades. Surface temperatures have been running much
colder than model forecasts today, and we've been playing "catch-up"
all day trying to stay ahead of cold air. Tried to maintain the
colder trend through Tuesday morning which puts temperatures real
close to freezing along I-80 during the morning rush hour.
Confidence is low in regards to temperatures during this time, and
will play a big role in precipitation type and potential icing. Warm
ground temperatures of late will also help mitigate widespread icing
on roads, but secondary roadways, sidewalks, elevated surfaces
including trees and power lines could all be impacted by ice.
Rain amounts will be tough to nail down as well. Convection-allowing
models have been generally suggesting a quarter to half inch of QPF
and locally higher amounts in areas where rain or freezing rain will
be most likely precip type. But again convective signatures in
output suggest higher totals will be spotty. Given freezing rain
accumulation modeling, higher rain rates will translate to lower ice
to liquid ratios. Thus rain amounts near a half inch would likely
translate to a quarter inch of ice accumulation if the surface was
below freezing. This is most likely to occur northwest of the Omaha
Metro where we have up to a quarter inch of ice accumulation. Along
I-80 amounts will likely be less and average up to a tenth.
Precipitation will work northeast during the day and likely change to
all snow before ending, though amounts less than an inch near I80
are expected. All precip should be done by the Tuesday evening rush
hour.
Tuesday night through Monday:
Broad mid level troughing will continue across much of the central
CONUS through the weekend, keeping temperatures near or below
normal. A shortwave trough marching through the region early in the
weekend will bring our next chance for precipitation. Right now rain
appears the most likely precip type, but could be rain or snow
especially in the overnight periods of Friday night and Saturday
night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 527 PM CST Mon Nov 9 2020
MVFR and IFR conditions are expected to be the primary flight
categories through the forecast period with a very busy and
complex winter weather set up. Currently, spotty drizzle continues
to float around eastern Nebraska and will continue to be possible
into the evening.
Models have struggled with the arrival and intensity of the
colder air as it has been moving into the area, leading to lower
than usual forecast confidence. Wind gusts are expected to max out
at around 25 kts, with the strongest winds being at KLNK and KOFK
overnight. As precipitation intensity increases overnight, a
broad transition zone in terms of precipitation will be present
with freezing rain and some sleet being possible at KLNK and KOMA
and points northeast and rain to the southeast. After 12z, some
of the freezing rain then gives way to snow at KOFK and moves east
and north, with some of it potentially clipping OMA and LNK.
After the precipitation moves out, quieter conditions are expected
to settle in.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory from midnight tonight to 3 PM CST
Tuesday for NEZ034-043>045-050>053-065>067-078-088.
Winter Weather Advisory from 9 PM this evening to 3 PM CST
Tuesday for NEZ011-012-015>018-030>033-042.
IA...Winter Weather Advisory from midnight tonight to 3 PM CST
Tuesday for IAZ043-055-056-069.
&&
DISCUSSION...Dergan
AVIATION...PetersenHazardous Weather Outlook National Weather Service Omaha/Valley NE 425 PM CST Mon Nov 9 2020 IAZ043-055-056-069-NEZ011-012-015>018-030>034-042>045-050>053- 065>067-078-088-101230- Monona-Harrison-Shelby-Pottawattamie-Knox-Cedar-Thurston-Antelope- Pierce-Wayne-Boone-Madison-Stanton-Cuming-Burt-Platte-Colfax- Dodge-Washington-Butler-Saunders-Douglas-Sarpy-Seward-Lancaster- Cass-Saline-Jefferson- 425 PM CST Mon Nov 9 2020 This Hazardous Weather Outlook is for portions of southwest Iowa...west central Iowa...east central Nebraska...northeast Nebraska and southeast Nebraska. .DAY ONE...Tonight and Tuesday Freezing rain or drizzle is likely in northeast Nebraska and parts of west central Iowa this evening, generally northwest of a Columbus to Onawa. Scattered showers with temperatures above freezing are likely across the rest of eastern Nebraska and western Iowa this evening. Precipitation will increase overnight as a system moves into the region. With temperatures cooling to near or below freezing, a mix of rain, freezing rain, snow and sleet are all possible. Snow amounting up to 4 inches is likely northwest of a Columbus to Onawa line. To the southeast of that line, freezing rain is most likely as temperatures drop to or below freezing through the night. Ice amounts of a tenth or two-tenths of an inch are possible. The precipitation is expected to lift to the northeast Tuesday afternoon and end before the evening rush hour. .DAYS TWO THROUGH SEVEN...Tuesday night through Monday The probability for hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. IAZ079-080-090-091-NEZ068-089>093-101230- Mills-Montgomery-Fremont-Page-Otoe-Gage-Johnson-Nemaha-Pawnee- Richardson- 425 PM CST Mon Nov 9 2020 This Hazardous Weather Outlook is for portions of southwest Iowa and southeast Nebraska. .DAY ONE...Tonight and Tuesday There is a slight chance for thunderstorms tonight as a strong storm system rolls into the region. Severe storms are not expected. Rain will continue Tuesday, with temperatures gradually falling to near freezing. Some sleet or freezing rain is possible, but accumulations of either should not amount to more than trace amounts of sleet of a light glaze of icing. .DAYS TWO THROUGH SEVEN...Tuesday night through Monday The probability for hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
12 ice storm, 4 heavy snow. Local standard time, as filed.
Numerous reports from public concerning ice. Multiple power outage reports. Numerous reports of damaged trees.
Numerous ice reports from the public. Maximum of 1.06 inches of flat ice reported.
Public reported 0.25 inches of flat ice.
Numerous ice reports from the public and power outages. Maximum of 0.25 inches of radial ice reported.
Public called in with a flat ice measurement of 0.62 inches. There were multiple reports of power outages.
Public reported icing of 0.62 inches via social media.
Considerable icing reported across the county. No official observation was noted.
Numerous ice reports from the public and power outages. Maximum of 0.50 inches of flat ice reported.
Public reported that ice had led to power outages and significant tree damage.
Numerous ice reports from the public. One report of 0.62 inches of flat ice.
Numerous ice reports from the public and power outages. Maximum of 0.33 inches of flat ice reported.
Numerous ice reports from the public and power outages. No reliable ice amounts reported.
Spotter reported 8 inches of snow fall.
Public reported 10 inches of snow fall.
Public reported 8.5 inches of snow fall.
Trained observer reported 9.0 inches of snow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nebraska in 2020Every state in 2020This day in weather historyWarnings in Nebraska, 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: 921079, 928165, 928170, 928166, 921080, 928162, 928163, 928167, 921077, 928164, 928168, 928169, 928171, 928172, 928173, 928382.