A relatively strong and cold weather system impacted southeast Arizona New Year's Eve through January 2nd. This storm resulted in heavy snow across area mountain ranges through New Year's Day, especially over 7000 feet in elevation with some locations receiving over a foot of snow.
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.
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 TWC wrote it up.
A relatively strong and cold weather system impacted southeast Arizona New Year's Eve through January 2nd. This storm resulted in heavy snow across area mountain ranges through New Year's Day, especially over 7000 feet in elevation with some locations receiving over a foot of snow. Heavy snow shifted to the lower elevations south and east of Tucson overnight on January 1st and on January 2nd. Snow levels dropped to 2500 feet and snow reports ranged from 2 to 7 inches on the valley floors.
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 31, 9:35 AM MST, 4 hours 25 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 935 AM MST Mon Dec 31 2018 .SYNOPSIS...An approaching storm system will bring rain and snow to the region later today through at least Tuesday. Snow levels will reach down to valley floors in many locations, especially south and east of Tucson. Dry and warmer the second half of the week before another storm system impacts the region late next weekend into early next week. && .DISCUSSION...Satellite imagery this morning showed high level cloud cover increasing across southeast Arizona which will overspread the area into this afternoon. Across the northern half of the state plenty of low to mid level cloud cover associated with a cold front that was dropping south across northern Arizona. Doppler radar showed scattered rain and snow showers extending from Las Vegas east to Winslow. As the cold front drops south this afternoon, scattered showers will be developing from western Pima county NE through Pinal/Gila counties to the White Mountains. Showers will become more numerous as the cold front slowly moves into the area this evening with snow levels falling as the night progresses. We have various winter weather headlines out for tonight above 3500 feet and that looks good. Big question for later tonight is will there be any accumulating snow at lower elevations which includes the Tucson metro area. Due to this uncertainty will not added the metro area into the winter weather advisory but the evening shift may have to hoist a short lead time depending on how everything evolves. Otherwise snow amounts across various elevations look pretty good at this time. The remainder of the forecast will be detailed in the afternoon discussion. && .AVIATION...Valid through 01/12Z. Clear skies this morning then SCT-BKN clouds AOA 20k ft AGL developing later this morning through the afternoon. Clouds lowering from north to south after 31/21Z to 8-12k ft with SCT -SHRA/-SHSN. After 01/03Z CIGS lowering to BKN-OVC 4-6k ft OVC 8-10k ft with areas MVFR CIGS and VSBYS in SHRA/SHSN through Tuesday morning with mountains mostly obscured. SFC winds southerly and increasing to 12- 19 kts with gusts to 30 kts by 31/18Z. After 01/02Z winds easing from west to east through the night to westerly 5-12 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...A southward moving storm system will spread gusty winds, rain and low elevation snow showers area wide later today into Tuesday, including significant mountain snows. Accumulating snow is likely as low as 3,500 feet on average later tonight into Tuesday morning. Dry weather will then take hold Wednesday through Friday. There is good potential for a warmer rain event later this coming weekend. 20-foot winds will generally remain light with the exception of today into tonight where south-southwest winds will gust into the 20-35 mph range. Temperatures will remain below normal through Thursday, then return to normal or slightly above normal into the weekend. && && .TWC WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 2 PM this afternoon to 5 PM MST Tuesday for AZZ510-511-514. Winter Weather Advisory from 5 PM this afternoon to 5 PM MST Tuesday for AZZ503-504-506>509-512-513-515. Hard Freeze Warning from 10 PM Tuesday to 9 AM MST Wednesday for AZZ502-504>506. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
The national radar mosaic for the moment the first event began.
2 winter storm. Local standard time, as filed.
Accumulating snow began on the afternoon of December 31. By the morning of January 1 estimated snowfall totals in the White Mountains above 7000 feet were one foot or greater.
Accumulating snow began on the afternoon of December 31. By the morning of January 1 estimated snowfall totals in the Pinaleno Mountains above 7000 feet were one foot or greater.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2018Every state in 2018This day in weather historyWarnings in Arizona, December 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: 796712, 796729.