Deep monsoon moisture brought heavy rain and hail to parts of northern Arizona.
Every event with a place to put it. 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.
Deep monsoon moisture brought heavy rain and hail to parts of northern Arizona.
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 Jul 19, 10:00 AM MST, 2 hours 15 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 1000 AM MST Thu Jul 19 2018 .SYNOPSIS...Expect afternoon and evening showers and thunderstorms through at least Saturday. The greatest coverage and highest potential for stronger storms will be over the Mogollon Rim and Yavapai County where areas of heavy rain could produce localized flooding. Warmer afternoon temperatures and less storm coverage may start on Sunday. && .UPDATE...12Z sounding showed a PW of 0.74 inch...down from 1.00 yesterday morning. Very little cloud cover this morning so there will be abundant solar heating this morning. Easterly flow up through 5H and then southwest winds above around 3H. This could help storms develop. We are expecting another active day today. Making some adjustments to the POPs this evening as high resolution models are indicating a few thunderstorm clusters lasting and moving into the lower elevations. && .PREV DISCUSSION /344 AM MST/... Cloud cover has been decreasing since midnight across northern Arizona, though the amount of monsoonal moisture overhead is expected to show little change through Saturday. So for today, expect showers and tstorms to develop across the high terrain by late morning and spread into the valleys this afternoon. Storm steering flow this afternoon will be very light, thus storms will be slow moving and may produce heavy rainfall amounts. Storms dropping south and westward off the Mogollon Rim will be headed into tstorm capes of 1000-2000 j/kg. The GFS shows another cyclonic mesoscale circulation late this afternoon, this one moving into the White Mtns. Something to keep an eye out for. For Friday and Saturday, the subtropical high pressure re- centers near Four Corners on Friday. This puts northern Arizona in very light south to southeast flow pattern with rich monsoon moisture through Saturday. Expect primarily afternoon and evening showers and thunderstorms with storms moving very slowly from south to north. Heavy rain and flash flooding will be the main storm threats. From Sunday through Wednesday - Progs continue to show drier air moving overhead above 500 mb (theta 330 surface). N0 changes were made to this period with the idea we will see a decrease in daytime storm coverage and fair weather overnight. Max temps up 2 to 5 degrees for this period vs today. && .AVIATION...For the 18Z package...VFR conditions and mostly clear skies this morning will transition to sct-nmrs shra/tsra with isold +tsra by 19Z-20Z. Convective activity most wdsprd between 21Z-02Z. Strongest storms will produce localized MVFR/IFR conditions and wind gusts to 50kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...An active monsoon pattern with scattered to numerous slow moving thunderstorms will continue today and Friday. Heavy rain and erratic thunderstorm winds will be the main threats. Outside of thunderstorms, winds will generally be light. Saturday through Monday...Thunderstorm chances will continue each day through the weekend into early next week. There is a possibility of a slight downturn in activity sometime next week. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...MAS/DL AVIATION...Peterson FIRE WEATHER...DB For Northern Arizona weather information visit weather.gov/flagstaff
Special Weather Statement National Weather Service Flagstaff AZ 1210 PM MST THU JUL 19 2018 AZZ015-192000- Western Mogollon Rim- 1210 PM MST THU JUL 19 2018 ...SIGNIFICANT WEATHER ADVISORY FOR COCONINO COUNTY UNTIL 100 PM MST... At 1210 PM MST, Doppler radar was tracking a strong thunderstorm over Flagstaff Mall, or over Flagstaff. this storm was nearly stationary. Dime size hail and winds in excess of 30 mph will be possible with this storm. Locations impacted include... Flagstaff, Flagstaff Mall, Cosnino and Walnut Canyon National Monument. 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. && LAT...LON 3515 11160 3523 11166 3528 11153 3519 11147 TIME...MOT...LOC 1910Z 231DEG 3KT 3521 11158
The Flagstaff radar (KFSX), 79 km away, was scanning. The volume nearest the first event began at 19:14 UTC.
4 flash flood, 2 heavy rain, 2 hail. Local standard time, as filed.
An alert rain gauge near the Flagstaff Mall reported 4.57 inches of rain in 1 hour and | 45 minutes.
Pictures on social media showed flooded parking lots at car dealer ships with water up to the hood of vehicles one mile east of the Flagstaff Mall. Other pictures showed 2.5 to 3 feet of water flowing in the normally dry Switzer Wash at 4th Street and Butler Avenue.
One inch diameter hail was reported by a NWS employee 3 miles south of the Flagstaff Mall.
Quarter-sized hail (1 inch in diameter) was reported by a trained spotter at 345 and 400 PM MST in Ash Fork.
South Verde Lakes Drive in Camp Verde was closed due to flash flooding.
The river gauge on Big Bug Creek at Mayer showed a 2.1 rise at 620 MST due to heavy rain from a thunderstorm over the Goodwin Fire scar. A second flood wave of the same height came at 1050 PM MST.
A trained spotter reported 1.61 inches of rain in around an hour. Dime sized (3/4 inch diameter) hail also fell.
Emergency Manager reported that flooding was impacting homes and shut down westbound lane of Interstate-40. Emergency shelter for people and large livestock established in Holbrook.
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, July 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: 778687, 778689, 778686, 778690, 781549, 781540, 778696, 781544.