S. created strong southwest gradient winds over southeast Arizona.
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 TWC wrote it up.
An upper level trough over the western U.S. created strong southwest gradient winds over southeast Arizona. Strong winds damaged one structure in Sierra Vista.
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 May 1, 4:00 PM MST, 1 hour earlier.
Area Forecast Discussion National Weather Service Tucson AZ 400 PM MST Tue May 1 2018 .SYNOPSIS...A low pressure system moving north of the area will bring isolated to scattered showers tonight. Isolated to scattered showers Wednesday will be mainly confined to the White Mountains. Expect quite cool temperatures Wednesday night, then building high pressure will bring much warmer temperatures Friday into this weekend. && .DISCUSSION...Deep upper trough over the western CONUS was contributing to cloudy skies and gusty south to southwest winds across southeast Arizona this afternoon. Expect isolated showers producing light rain to develop early this evening mainly west to northwest of Tucson. Isolated to scattered showers should move eastward across central/eastern portions of this forecast area later tonight. Snow levels are forecast to fall to 7000-7500 feet by daybreak Wednesday. Several HRRR solutions as well as the 01/12Z Univ of AZ WRF-NAM and WRF-GFS suggest the best period for measurable rainfall to occur within the Tucson metro area will be generally from 8 PM MST to around midnight. Rainfall amounts at lower elevations should mostly be less than one tenth of an inch. Liquid amounts in the mountains and particularly from the Catalina/Rincon Mountains to the White Mountains expected to range from about 0.10" - 0.50", with the highest amounts favoring the White Mountains. Snow accumulations above 7000 feet may briefly approach 5-6 inches White Mountains; 3 inches Mount Graham, and 1-2 inches Catalina Mountains. Isolated to scattered showers northeast of Tucson and especially White Mountains Wednesday forecast to end around sunset Wednesday evening. Thereafter, strengthening upper ridge over the western CONUS will translate into dry conditions Thursday into early next week. After cooler temperatures Wednesday, a warming trend will begin Thursday before much warmer temperatures prevail Friday into early next week. The first official 100 degree temperature for the Tucson metro area appears increasingly likely on Sunday, then well above normal temps to continue Monday and Tuesday. Gusty winds continuing into Wednesday then markedly less wind Wednesday night. The combination of clearing skies or clear skies, and light winds will produce ideal radiational cooling conditions late Wednesday night. A few locales in the Sulphur Springs Valley may very briefly encroach upon freezing temperatures late Wednesday night, but widespread freezing temperatures are not expected to occur. && .AVIATION...Valid through 03/00Z. Isolated -SHRA mainly west to northwest of KTUS early this evening, then isolated to scattered -SHRA KTUS vicinity eastward to New Mexico after about 02/03Z and continuing the rest of tonight. The best timing for -SHRA KTUS vicinity appears to be from 03Z-07Z Wednesday. Any -SHRA around daybreak Wednesday and continuing into Wednesday afternoon should occur northeast of KTUS. Otherwise, cloud decks becoming 4k-8k ft AGL this evening and continuing into Wednesday morning. Cloud decks 6k-10k ft AGL Wednesday afternoon then decreasing clouds Wednesday evening. Surface wind this evening and Wednesday afternoon swly/wly 10-25 kts with gusts near 35-40 kts. Surface wind late tonight and Wednesday morning sely to swly 5-15 kts with gusts near 25 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...A Red Flag Warning is in effect until 7 PM MST this evening for southern portions of Fire Weather Zones 151 and 152. The combination of gusty south to west winds, low relative humidity and a high to very high fire danger will create critical fire conditions. A Fire Weather Watch is in effect Wednesday afternoon for much of Cochise County. The combination of gusty southwest to west winds, low relative humidity and a high to very high fire danger may create critical fire conditions. Lighter winds Thursday into this weekend will mitigate critical fire conditions. However, afternoon gusts will occur due to strong daytime heating. Below normal temperatures Wednesday and Thursday will be followed with a strong warming trend Friday into this weekend. The warmest temperatures so far this year will be likely on Sunday. && .TWC WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 7 PM MST this evening for AZZ151-152. Wind Advisory until 7 PM MST this evening for AZZ503-507-508. Fire Weather Watch Wednesday afternoon for AZZ151-152. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
The national radar mosaic for the moment the first event began.
1 strong wind. Local standard time, as filed.
Minor wind damage occurred at the site of a commercial building that was under construction in Sierra Vista. Several of the metal studs were bent and dislodged from the slab.
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, May 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: 745491.