Abundant moisture over northern brought scattered thunderstorms. One storm produce severe hail.
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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.
Abundant moisture over northern brought scattered thunderstorms. One storm produce severe hail.
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 2, 2:26 PM MST, 2 hours 44 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 226 PM MST Sun Sep 2 2018 .SYNOPSIS...The chance for showers and thunderstorms will continue through the early part of this week. Thunderstorms will be most numerous from the Mogollon Rim northward. Otherwise, expect cool mornings and near normal high temperatures through the period. A drying trend is expected toward the end of the week. && .DISCUSSION... More showers and thunderstorms have developed again this afternoon. A notable weakening in the flow aloft today has transitioned us toward more of a flash flood threat than the severe weather we saw yesterday. This weak flow aloft will result in less shear and slow storm motion promoting the threat of heavy rainfall and flash flooding. These slower-moving storms are expected to develop each day through at least Tuesday. Eventually, warmer temperatures aloft develop as high pressure and drier westerly flow forms off the California coast, and we expect a drying and warming trend toward the end of the week. && .AVIATION...For the 00Z package...Scattered thunderstorms will continue into this evening, especially along and north of the Mogollon Rim. MVFR/IFR conditions along with gusty and erratic winds are possible near thunderstorms. Storm coverage is likely to decrease overnight. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Anticipate scattered showers and thundertorms, mainly across higher terrain features, again Monday and Tuesday. Wednesday through Friday...A significant downward trend in showers and thunderstorms is forecast, with daytime temperatures climbing back to near or slightly above normal values. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...KD/TPS AVIATION...KD FIRE WEATHER...KD For Northern Arizona weather information visit weather.gov/flagstaff
Special Weather Statement National Weather Service Flagstaff AZ 1132 AM MST SUN SEP 2 2018 AZZ013-016-021915- Little Colorado River Valley in Navajo County-Eastern Mogollon Rim- 1132 AM MST SUN SEP 2 2018 ...SIGNIFICANT WEATHER ADVISORY FOR NAVAJO COUNTY UNTIL 1215 PM MST... At 1130 AM MST, Doppler radar was tracking a strong thunderstorm 7 miles northwest of Aripine, or 16 miles northeast of Forest Lakes, moving east at 5 mph. Nickel size hail and winds in excess of 30 mph will be possible with this storm. Locations impacted include... Heber-Overgaard. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. && LAT...LON 3439 11058 3447 11064 3457 11051 3443 11042 TIME...MOT...LOC 1830Z 252DEG 6KT 3445 11055 TPS
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
300 PM MST SUN SEP 2 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1040 AM HAIL SAINT MICHAELS 35.66N 109.09W
09/01/2018 E1.75 INCH APACHE AZ PUBLIC
PUBLIC REPORT VIA SOCIAL MEDIA OF GOLF BALL
AND HALF-DOLLAR SIZE HAIL FROM A SEVERE
THUNDERSTORM PASSING OVER THEIR LOCATION.
&&
NLThe Flagstaff radar (KFSX), 70 km away, was scanning. The volume nearest the first event began at 00:08 UTC.
1 hail. Local standard time, as filed.
A trained spotter reported golf ball sized hail (1 3/4 inch diameter) four miles south of Jakes Corner.
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, September 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: 786460.