Winter Storm and Winter Weather in Missouri, December 29 to 30, 2020

Name: Winter Storm and Winter Weather in Missouri, December 29 to 30, 2020
Start: 2020-12-29T05:30
End: 2020-12-30T00:00
Location: Missouri

December 29 to 30, 2020 · NWS EAX · 15 events in 15 counties and zones

Where it happened

Every event with a place to put it; 15 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 1
Injuries: 1
Property damage: $10,000
Crop damage: None recorded
Events: 15

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.

What happened

The episode as NWS EAX wrote it up.

A strong system ejected eastward into the central part of the country just after Christmas. Precipitation started out as snow, but as warm air aloft moved in it switched over to liquid rain, freezing on contact with all sub-freezing surfaces at ground level. The worst of the freezing rain formed generally along the HWY 36 corridor, producing numerous power outages and causing several vehicle accidents. One such accident in Macon county proved fatal as a car slid off an icy road and killed one of its occupants.

What forecasters said that day

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 Kansas City, MO wrote its last area forecast discussion before the first event at Dec 29, 4:30 AM CST, 1 hour earlier.

Area forecast discussion, Dec 29, 4:30 AM CST, 1 hour before

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
430 AM CST Tue Dec 29 2020

.Discussion...
Issued at 429 AM  CST TUE DEC 29 2020

...WINTER WEATHER RETURNS TO THE REGION TODAY...

Key Points:

-Winter storm is expected to impact the region today.  Light snow is
expected to transition to ice, prior to the surface warming above
freezing.  Have raised icing amounts especially across northern
Missouri. With mixed precipitation and significant amounts of ice
expected across northern Missouri, have transitioned to a winter
storm warning along and north of a line from St. Joseph to
Unionville.

-Second winter storm is looking more likely for New Years Day.  This
system also appears to have a fair amount of warm air above the
surface, potentially leading to another wintry mix.

Large upper trough is expected to move from the intermountain west
into the Central Plains today.  Plenty of moisture available for
this system with the Gulf wide open.  As low-level warm air/thetae
advection increases ahead of the wave, isentropic lift develops and
precipitation is expected to develop across the region.  Warm air
advection aloft will lead to a warm nose developing aloft from 700-
900 mb resulting in precipitation type transitioning from snow to
ice and then eventually rain; however, surface warming will lag
warming aloft resulting in significant icing potential.  Have
upgraded northwest Missouri to north central Missouri to winter
storm warning with significant amounts of sleet and freezing rain
expected.  Precipitation type is expected to transition to ice from
south to north through the morning hours today, and remain ice
through the afternoon hours in the warning area.  Surface
temperatures should eventually warm above freezing this evening, but
until this occurs, a prolonged icing event is expected.  Short term
high res models are also suggesting this potential, with
RAP/HRRR/NAM Nest suggesting 0.5-0.75" of ice through the afternoon
hours.

Farther to the south, ice amounts are expected to be less as
exceeding freezing threshold at the surface is expected to occur
sooner from south to north. Have continued the winter weather
advisory in these locations.

Of other concern will be the strong southeast winds that are
expected today ahead of the surface low.  Sustained winds of 15-20
mph with gusts of 20-25 mph will be common through the late morning
and early afternoon hours.  If significant ice accumulation could
occur prior to this, power outages can be expected with down tree
limbs and power lines. As pressure gradient relaxes slightly through
the afternoon hours, should see a downward trend in surface winds.

Precipitation is expected to continue through the late afternoon and
evening hours as frontogenetic band of precipitation lingers through
the evening hours.  By this point, precipitation should be liquid,
with areas along and south of highway 36 above freezing. Warm air
should continue to expand northward with strong south winds.

Cold front is expected to work southeast across the region early on
Wednesday bringing an end to precipitation. With cold air advection
continuing through the daylight hours on Wednesday, should see non-
diurnal temperatures with minimal recover through the afternoon
hours.

Attention thereafter is on second storm system currently just off
the southern California coast.  This system is expected to dig into
northern Mexico on Thursday and into the central Plains on Thursday
into Friday.  Models have continued to trend west with this system,
bringing more precipitation to central and northern Missouri than
previously expected.  A significant amount of warm air aloft is
expected to wrap into this system as well, potentially leading to
another mixed precipitation event on New Years Day.

Remainder of the seven day forecast remains dry at the time, with
temperatures returning to seasonal norms this weekend.  That could
be impacted by lingering snow/ice from the two storm systems this
week.

&&

.Aviation...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1056 PM CST MON DEC 28 2020

Still looking at incoming precipitation eventually making it to
the terminals about as previously advertised, roughly around
sunrise. Initially precipitation will be snow or ice, then
transitioning to ice/freezing rain and sleet through the late
morning and early afternoon. By late afternoon enough warm air
should be moving in to get rain to stay melted on surfaces. In the
meantime through Tuesday morning and early afternoon surfaces will
be very slick. Low level wind shear is also on track to form above
the terminals with very strong low level winds.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Winter Storm Warning until 6 AM CST Wednesday for KSZ025-102.

     Winter Weather Advisory until 6 PM CST this evening for KSZ057-
     103>105.

MO...Winter Weather Advisory from 9 AM this morning to 6 PM CST this
     evening for MOZ022>025-030>032-038-039.

     Winter Storm Warning until 6 AM CST Wednesday for MOZ001>007-
     011>016-020.

     Winter Weather Advisory until 6 PM CST this evening for MOZ021-
     028-029-037-043.

     Winter Weather Advisory from 9 AM this morning to 6 AM CST
     Wednesday for MOZ008-017.

&&

Discussion...BT
Aviation...Leighton

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

14 winter storm, 1 winter weather. Local standard time, as filed.

Winter Storm, Atchison

When: December 29, 5:30 AM CST to 8:00 PM CST
Where: Atchison forecast zone
Reported by: ASOS
Coordinates: 40.431, -95.428 (the zone’s center; the record gives no point)

During the day on December 29, a potent winter storm moved into the area. The precipitation started as primarily snow during the morning hours producing a couple inches of accumulation, but switched to freezing rain just before 10 am as warm air aloft moved over the area. Moderate, to at times heavy rain ensued through the rest of the morning and early to middle afternoon hours, before eventually moving out by the evening hours. The main impact from this storm was several power outages around the area. Due to the rain rates, not all of the nearly 1 inch of liquid precipitation accreted on surfaces, but a quarter to half inch did accrete, causing a significant disruption to the power, and closing numerous roads.

Winter Storm, Nodaway

When: December 29, 5:30 AM CST to 8:00 PM CST
Where: Nodaway forecast zone
Reported by: ASOS
Coordinates: 40.361, -94.883 (the zone’s center; the record gives no point)

Winter Storm, Holt

When: December 29, 5:30 AM CST to 8:00 PM CST
Where: Holt forecast zone
Reported by: ASOS
Coordinates: 40.094, -95.215 (the zone’s center; the record gives no point)

Winter Storm, Andrew

When: December 29, 5:30 AM CST to 8:00 PM CST
Where: Andrew forecast zone
Reported by: ASOS
Coordinates: 39.984, -94.802 (the zone’s center; the record gives no point)

Winter Storm, Worth

When: December 29, 5:30 AM CST to 8:00 PM CST
Where: Worth forecast zone
Reported by: ASOS
Coordinates: 40.479, -94.422 (the zone’s center; the record gives no point)

Winter Storm, Gentry

When: December 29, 5:30 AM CST to 8:00 PM CST
Where: Gentry forecast zone
Reported by: ASOS
Coordinates: 40.212, -94.410 (the zone’s center; the record gives no point)

Winter Storm, Buchanan

When: December 29, 7:00 AM CST to 8:00 PM CST
Where: Buchanan forecast zone
Reported by: Broadcast Media
Coordinates: 39.660, -94.806 (the zone’s center; the record gives no point)

During the day on December 29, a potent winter storm moved into the area. The precipitation started as primarily snow during the morning hours producing a couple inches of accumulation, but switched to freezing rain just before 10 am as warm air aloft moved over the area. Moderate, to at times heavy rain ensued through the rest of the morning and early to middle afternoon hours, before eventually moving out by the evening hours. The main impact from this storm was 10,000 to 20,000 without power in and around the St. Joseph area. Due to the rain rates, not all of the nearly 1 inch of liquid precipitation accreted on surfaces, but a quarter to half inch did accrete, causing a significant disruption to the power, and closing numerous roads.

Winter Storm, De Kalb

When: December 29, 7:00 AM CST to 8:00 PM CST
Where: De Kalb forecast zone
Reported by: Broadcast Media
Coordinates: 39.893, -94.405 (the zone’s center; the record gives no point)

During the day on December 29, a potent winter storm moved into the area. The precipitation started as primarily snow during the morning hours producing a couple inches of accumulation, but switched to freezing rain just before 10 am as warm air aloft moved over the area. Moderate, to at times heavy rain ensued through the rest of the morning and early to middle afternoon hours, before eventually moving out by the evening hours. Due to the rain rates, not all of the nearly 1 inch of liquid precipitation accreted on surfaces, but a quarter to half inch did accrete, causing a significant disruption to the power, and closing numerous roads.

Winter Storm, Harrison

When: December 29, 7:30 AM CST to 7:00 PM CST
Where: Harrison forecast zone
Reported by: ASOS
Coordinates: 40.355, -93.992 (the zone’s center; the record gives no point)

Winter Storm, Mercer

When: December 29, 7:30 AM CST to 7:00 PM CST
Where: Mercer forecast zone
Reported by: ASOS
Coordinates: 40.422, -93.569 (the zone’s center; the record gives no point)

Winter Storm, Putnam

When: December 29, 7:30 AM CST to 7:00 PM CST
Where: Putnam forecast zone
Reported by: ASOS
Coordinates: 40.479, -93.016 (the zone’s center; the record gives no point)

Winter Storm, Sullivan

When: December 29, 10:00 AM CST to December 30, 12:00 AM CST
Where: Sullivan forecast zone
Reported by: ASOS
Coordinates: 40.211, -93.111 (the zone’s center; the record gives no point)

During the day on December 29, a potent winter storm moved into the area. The precipitation started as primarily snow during the morning hours producing a couple inches of accumulation, but switched to freezing rain just before 1 pm as warm air aloft moved over the area. Moderate, to at times heavy rain ensued through the rest of the morning and early to middle afternoon hours, before eventually moving out by the evening hours. The main impact from this storm was several power outages around the area. Due to the rain rates, not all of the nearly 1 inch of liquid precipitation accreted on surfaces, but a quarter to half inch did accrete, causing a significant disruption to the power, and closing numerous roads.

Winter Storm, Grundy

When: December 29, 10:00 AM CST to December 30, 12:00 AM CST
Where: Grundy forecast zone
Reported by: ASOS
Coordinates: 40.114, -93.565 (the zone’s center; the record gives no point)

During the day on December 29, a potent winter storm moved into the area. The precipitation started as primarily snow during the morning hours producing a couple inches of accumulation, but switched to freezing rain just before 1 pm as warm air aloft moved over the area. Moderate, to at times heavy rain ensued through the rest of the morning and early to middle afternoon hours, before eventually moving out by the evening hours. The main impact from this storm was several power outages around the area. Due to the rain rates, not all of the nearly 1 inch of liquid precipitation accreted on surfaces, but a quarter to half inch did accrete, causing a significant disruption to the power, and closing numerous roads.

Winter Storm, Daviess

When: December 29, 10:00 AM CST to December 30, 12:00 AM CST
Where: Daviess forecast zone
Reported by: ASOS
Coordinates: 39.961, -93.985 (the zone’s center; the record gives no point)

During the day on December 29, a potent winter storm moved into the area. The precipitation started as primarily snow during the morning hours producing a couple inches of accumulation, but switched to freezing rain just before 1 pm as warm air aloft moved over the area. Moderate, to at times heavy rain ensued through the rest of the morning and early to middle afternoon hours, before eventually moving out by the evening hours. The main impact from this storm was several power outages around the area. Due to the rain rates, not all of the nearly 1 inch of liquid precipitation accreted on surfaces, but a quarter to half inch did accrete, causing a significant disruption to the power, and closing numerous roads.

Winter Weather, Macon

When: December 29, 12:38 PM CST
Where: Macon forecast zone
Deaths: 0 direct, 1 indirect
Injuries: 0 direct, 1 indirect
Property damage: $10,000
Reported by: Law Enforcement
Coordinates: 39.831, -92.565 (the zone’s center; the record gives no point)

As a winter storm moved into the general area, Macon County received light snow and freezing rain. Along Highway 63 near Excello - between Macon and Moberly - a box truck used by two males slid off ice covered roadway onto the east side of the roadway, and overturned. Both men were not wearing seat belts. The driver survived with injuries, while the driver did not survive his injuries.

Missouri Highway Patrol crash report: https://www.mshp.dps.missouri.gov/HP68/AccidentDetailsAction?ACC_RPT_NUM=200648868 .

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Winter Weather, Macon	2020-12-29	62	Male	Vehicle/Towed Trailer	Indirect

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Missouri in 2020 Every state in 2020 This day in weather history Warnings in Missouri, December 2020

Sources

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: 932180, 932181, 932182, 932183, 932185, 932186, 932179, 932184, 932187, 932188, 932189, 932190, 932191, 932192, 932193.