A weak low centered over Baja California gradually moved northward across Arizona during the day. Moisture over far northern Mexico moved northward during the day and combined with upward motion to create strong to severe thunderstorms over the western part of the White Mountains.
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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 weak low centered over Baja California gradually moved northward across Arizona during the day. Moisture over far northern Mexico moved northward during the day and combined with upward motion to create strong to severe thunderstorms over the western part of the White Mountains.
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 Sep 27, 2:43 PM MST, 1 hour earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 243 PM MST TUE SEP 27 2016 .SYNOPSIS...A low pressure system currently over southwestern Arizona will gradually move northward through Thursday. Expect increasing chances of showers and thunderstorms across northern Arizona through Thursday then decreasing on Friday. Dry air is forecast to move in over the weekend. Near normal temperatures will continue. && .DISCUSSION... Water vapor loop shows the weak upper low centered over southwestern AZ this afternoon and we are finally seeing some widely scattered and light convection developing in Apache county this afternoon. The upper low to gradually move northward across Arizona through Thursday. For tonight we have scaled back precip chances as most recent models show southeast flow to persist in a rather stable airmass. Wednesday through Thursday night...Winds aloft to become southerly on Wednesday with a decent moisture plume moving northward into AZ. We are expecting greater precip coverage Wednesday and Thursday due to the moisture increase. The best chance for thunderstorms should be from the afternoon into the early evening hours in response to peak daytime heating and instability. Friday through Tuesday. Progs in good agreement showing dry air moving in from the west on Friday. Kept the slight chance of showers in for this transition period. From Friday night onward dry weather is expected with occasional high clouds streaming across the northland. && .AVIATION...For the 00Z package...look for Widely scattered -SHRA and isolated -tsra through 12Z weds...then scattered -SHRA/-TSRA spreading northward through the day. MVFR conditions possible in heavier storms. Aviation discussion not updated for TAF amendments. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...DL AVIATION...DL For Northern Arizona weather information visit weather.gov/flagstaff
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
232 PM MST TUE SEP 27 2016
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0232 PM HAIL 3 N SHOW LOW 34.28N 110.04W
09/27/2016 E0.50 INCH NAVAJO AZ TRAINED SPOTTER
&&
EVENT NUMBER FGZ1600245
041The Flagstaff radar (KFSX), 111 km away, was scanning. The volume nearest the first event began at 22:43 UTC.
1 hail. Local standard time, as filed.
Trained spotters reported one half inch to one inch diameter hail covering the ground between 2 and 8 miles north of Show Low.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2016Every state in 2016This day in weather historyWarnings in Arizona, September 2016
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: 659830.