Arizona, 2018Winter Storm in Arizona, December 27 to 28, 2018
December 27 to 28, 2018 · NWS TWC · 2 events in 2 counties and zones
A winter storm impacted southeast Arizona overnight on December 27 into the morning hours of December 28. Heavy snow fell on the mountain tops and the snow level reached down to 4000 feet impacting lower elevation areas.
Every event with a place to put it; 2 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
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- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 2
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.
A winter storm impacted southeast Arizona overnight on December 27 into the morning hours of December 28. Heavy snow fell on the mountain tops and the snow level reached down to 4000 feet impacting lower elevation areas.
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 Tucson, AZ wrote its last area forecast discussion before the first event at Dec 27, 2:26 PM MST, 3 hours 14 minutes earlier.
Area forecast discussion, Dec 27, 2:26 PM MST, 3 hours 14 minutes before
Area Forecast Discussion
National Weather Service Tucson AZ
226 PM MST Thu Dec 27 2018
.SYNOPSIS...Widespread valley rain and mountain snow showers tonight
as a low pressure system moves into northern Arizona. Valley rain
and mountain snow to continue Friday especially east of Tucson, then
precipitation ending Friday night. Expect freezing temperatures or a
hard freeze across the lower deserts Friday night and Saturday
night. Dry conditions will then prevail across much of the area
Saturday into the middle of next week.
&&
.DISCUSSION...The next storm system remained on track as it
continued to drop southward into northern Arizona this afternoon.
Scattered showers were already developing along the Rim and just
north of Phoenix this afternoon. As the system tracks farther south,
showers will form across the area this evening with the bulk of the
precipitation occurring tonight and early Friday. A Winter Weather
Advisory for above 5000 feet will remain in effect for later this
evening through Friday as another round of accumulating snow can be
anticipated in the mountains. The system will also usher in a much
colder air mass which will linger for several days. Most of the
heavy snowfall will be in the mountains, but if the timing of
showers lines up just right with the coldest temperatures snow may
accumulate at elevations as low as 3500 to 4000 feet. Otherwise,
just expecting a dusting of snow in the valleys of Cochise county.
The system will be slow to exit the area with the coldest air
spreading in during the day on Friday. This will set the stage for
the coldest nights of the season so far starting Friday night. Thus,
Freeze and Hard Freeze Warnings have been posted for the lower
desert valleys from around Tucson to Ajo and Casa Grande Friday and
Saturday nights. Once the system exits the area by Sunday, mainly
dry conditions can be anticipate with below normal daytime
temperatures.
&&
.AVIATION...Valid through 29/00Z.
Isolated -SHRA developing west to north of KTUS late this afternoon,
then scattered to numerous valley -SHRA and mountain
-SHSN tonight. Precip ending vicinity KTUS westward around 28/14Z,
but continuing Friday morning and afternoon east of KTUS. MVFR
conditions to occur tonight and tomorrow morning especially across
higher terrain. Skies will gradually clear from west to east
starting Friday afternoon. Surface wind this afternoon through
Friday afternoon mainly swly 8-18 kts with occasional gusts near 25
kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Isolated showers developing west to north
of Tucson this afternoon followed by widespread valley rain and
mountain snow tonight. Mainly dry conditions Tucson vicinity
westward Friday, but scattered showers to prevail east of Tucson. A
slight chance of rain and snow showers continues east of Tucson
Friday night. Saturday there is a slight chance for rain/snow
showers in southeast Cochise County, then dry Sunday, and a slight
chance rain/snow mainly in the White Mountains Monday. After Monday
expect dry conditions. Occasionally gusty southwest to northwest
winds will prevail this afternoon into Friday. Otherwise, 20-foot
winds will be under 15 mph.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 8 PM this evening to 5 PM MST Friday
for AZZ510.
Winter Weather Advisory from 8 PM this evening to 8 AM MST Friday
for AZZ511-514.
Winter Weather Advisory from 8 AM to 5 PM MST Friday for AZZ512.
Freeze Warning from late Friday night through Saturday morning for
AZZ501-502-504-505.
Freeze Warning from late Saturday night through Sunday morning for
AZZ501-502-504-505.
Hard Freeze Warning from late Friday night through Saturday morning
for AZZ506.
Hard Freeze Warning from late Saturday night through Sunday morning
for AZZ506.
&&
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Winter Storm, Santa Catalina and Rincon Mountains
- When
- December 27, 5:40 PM MST to December 28, 5:00 PM MST
- Where
- Santa Catalina and Rincon Mountains forecast zone
- Reported by
- Public
- Coordinates
- 32.501, -111.567 (the zone’s center; the record gives no point)
Heavy snow fell in the Catalinas with Summerhaven and Mount Lemmon Ski Valley reporting more than 15 inches of snow. A semi-tractor trailer jackknifed in the snowy conditions on Mount Lemmon Highway, blocking both lanes of traffic. The road closure resulted in about twenty people whose vehicles were farther up mountain having to spend the night in a shelter.
Winter Storm, Galiuro and Pinaleno Mountains
- When
- December 27, 5:40 PM MST to December 28, 5:00 PM MST
- Where
- Galiuro and Pinaleno Mountains forecast zone
- Reported by
- Public
- Coordinates
- 32.572, -110.328 (the zone’s center; the record gives no point)
Bands of heavy snow impacted the higher elevations of the Pinaleno mountains with snowfall estimates on Mt. Graham of one foot or greater.
- Winter Storm
- A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Tornado and Flash Flooding in Mississippi, December 27 to 28, 20181 injured · $4.8 million · EF0 · 49 events
- Blizzard and Winter Storm in Kansas, December 27, 20181 death · 50 kt wind · 19 events
- Flash Flooding in Mississippi, December 27 to 28, 2018$3.3 million · 3 events
- Flash Flooding and Damaging Wind in Alabama, December 27 to 28, 2018$810,000 · 52 kt wind · 4 events
- Flash Flooding and Flood in Louisiana, December 27 to 28, 2018$500,000 · 4 events
- Tornadoes and Flash Flooding in Louisiana, December 27, 2018$33,000 · EF1 · 8 events
- Damaging Winds in Louisiana, December 27, 20181 injured · $50,000 · 50 kt wind · 6 events
- Strong Wind in Illinois, December 27, 2018$19,000 · 19 events
- Blizzard and Heavy Snow in New Mexico, December 27 to 29, 201827 events
- Damaging Winds in Mississippi, December 27 to 31, 2018$27,000 · 50 kt wind · 6 events
- Blizzard in South Dakota, December 27 to 28, 201825 events
- Strong Wind in Tennessee, December 27, 2018$25,000 · 3 events
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: 796657, 796665.