A strong late season low pressure system moved across Arizona. Light snow of an inch or more fell over an area above 6000 feet roughly north and east of Payson to the Four Corners.
Every event with a place to put it; 1 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 FGZ wrote it up.
A strong late season low pressure system moved across Arizona. Light snow of an inch or more fell over an area above 6000 feet roughly north and east of Payson to the Four Corners. The area upwind from the Black Mesa picked up the most snow.
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 Flagstaff, AZ wrote its last area forecast discussion before the first event at May 17, 2:57 PM MST, 6 hours 3 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 257 PM MST Wed May 17 2017 .SYNOPSIS...A strong cold front will drop south tonight delivering a round of gusty winds and cooler temperatures along with a band of showers and thunderstorms. The chance of showers and cool temperatures will linger Thursday before warmer weather moves into the area for the weekend and early next week. && .DISCUSSION...A change to wet and cool conditions across northern Arizona will occur tonight and last through the end of the week before warming fair conditions move into the region this weekend and into next week. This change in the weather pattern is due to a strong low pressure system moving across the Great Basin. A cold front dropping out of this system will bring seasonably cool conditions and some shower activity as it moves across the state this evening and overnight. Most of the moisture associated with this system will stay north of the Mogollon Rim, with the heavies precipitation looking to fall over the Northern stretches of Navajo and Apache counties. While most locations will see the bulk of precipitation fall as rain from this system some locations could see a few snowflakes fall with little to no accumulations below 7200 feet. The biggest winter impacts are expected to occur over the Chuska Mountains of Northern Apache County. Route 12 over Buffalo Pass is expected to see winter driving conditions as around 2 inches of snow is expected to occur with the latest forecast runs. Confidence over amounts is relatively low for this close to the system, some model suites show a wide range of precipitation amounts for this frontal passage. As the event moves across the area tonight expect updates as satellite and radar sampling helps hone in precipitation amounts. Clearing conditions are expected Thursday morning as the precipitation associated with the cold front exits the state. By Thursday afternoon some convection associated with the moist environment and steep lapse rates could trigger some shower activity. Another lobe of instability will rotate through the area Thursday night and Friday morning bringing a second round of potentially widespread showers across much of Northern Arizona. As this instability exits the region the parent low pressure system will transition from the Rocky Mountains to the the northern great plains. A ridge of high pressure will slide over the southwest replacing cool unsettled conditions with warm clement weather through the weekend and into next week. && .AVIATION...For the 00Z package...Southwest gusting 30-40kts will decrease this evening...becoming northwesterly behind the front dropping southward from Utah. Expect MVFR conditions in heavier showers, generally along and northeast of the Mogollon Rim. Widely scattered showers will re-develop Thursday afternoon over the higher terrain, with isolated MVFR conditions expected. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...A cold front will move southward across the forecast area with scattered showers and thunderstorms expected overnight, most numerous north and east of the Mogollon Rim. Weakening southwest winds will turn sharply to the northwest with the passage of the front. Drying conditions, cool temperatures, and lighter winds are expected Thursday and Friday Saturday through Monday...Expect warming conditions and typical light breezes as dry westerly flow develops over the region. && .FGZ WATCHES/WARNINGS/ADVISORIES...Wind Advisory until 8 PM MST this evening FOR AZZ004-007-009-011>017-039-040. && PUBLIC...Suk AVIATION...BAK FIRE WEATHER...BAK For Northern Arizona weather information visit weather.gov/flagstaff
Hazardous Weather Outlook National Weather Service Flagstaff AZ 403 AM MST Wed May 17 2017 AZZ004-007-009-011>017-039-040-180100- Kaibab Plateau-Coconino Plateau- Northeast Plateaus and Mesas Hwy 264 Northward- Chuska Mountains and Defiance Plateau- Little Colorado River Valley in Coconino County- Little Colorado River Valley in Navajo County- Little Colorado River Valley in Apache County- Western Mogollon Rim-Eastern Mogollon Rim-White Mountains- Black Mesa Area-Northeast Plateaus and Mesas South of Hwy 264- 403 AM MST Wed May 17 2017 This Hazardous Weather Outlook is for portions of north central Arizona...northeast Arizona and west central Arizona. .DAY ONE...Today and Tonight A strong cold front will bring another round of strong west to southwest winds today. Wind gusts in the 35 to 45 mph range are likely along and north of the Mogollon Rim and a Wind Advisory is in effect. Showers and thunderstorms will spread from north to south this afternoon through late tonight along the cold front. Some light snow accumulation is possible tonight above 7000 to 8000 feet. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Showers and thunderstorms along the cold front will reach the White Mountains Thursday morning. Shower activity will decrease later Thursday into Friday. Moderating temperatures and dry weather are anticipated this weekend and early next week. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
620 PM MST WED MAY 17 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0545 PM SNOW 1 N JACOB LAKE 36.73N 112.21W
05/17/2017 M2.0 INCH COCONINO AZ PUBLIC
STILL SNOWING.
&&
DGVThe national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
Six inches of snow fell in Pi on at 6360 MSL in 12 hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2017Every state in 2017This day in weather historyWarnings in Arizona, May 2017
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: 691216.