Alert archive / Arizona / Severe Thunderstorm Warnings in 2018
Severe Thunderstorm Warning 190, NWS Flagstaff, AZ
NWS Flagstaff, AZ issued this severe thunderstorm warning at Oct 21, 2018, 4:06 PM MDT for Navajo County, Arizona. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Oct 21, 2018, 4:06 PM MDT (22:06 UTC)
- Expired
- Oct 21, 2018, 4:45 PM MDT
- In force
- 39 min
- Issued by
- NWS Flagstaff, AZ
- Area
- Storm-based polygon
- Hail
- 1.25 in
- Wind
- 50.0 mph
County Navajo County, AZ
The radar
The Flagstaff radar (KFSX), 122 km from the middle of the area, began a volume at 22:06 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 10.1 hours before the alert went out and 136 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 358 J/kg
- Mixed-layer CIN
- -73 J/kg
- Mixed-layer LCL
- 1094 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 123 m²/s²
- 0-3 km storm-relative helicity
- 174 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Oct 21, 11:42 AM MDT, 4 hours 24 minutes earlier.
Area forecast discussion, Oct 21, 11:42 AM MDT, 4 hours 24 minutes before
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</html>In the hours before
Special weather statement, Oct 21, 3:40 PM MDT, 26 minutes before
Special Weather Statement National Weather Service Flagstaff AZ 240 PM MST SUN OCT 21 2018 AZZ012-013-040-212230- Little Colorado River Valley in Navajo County- Little Colorado River Valley in Coconino County- Northeast Plateaus and Mesas South of Hwy 264- 240 PM MST SUN OCT 21 2018 ...SIGNIFICANT WEATHER ADVISORY FOR NAVAJO AND COCONINO COUNTIES UNTIL 330 PM MST... At 239 PM MST, Doppler radar was tracking two strong thunderstorms 9 miles east of Rimmy Jims, or 12 miles northwest of Winslow, moving east at 10 mph. Nickel size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Winslow and Homolovi State Park Campground. 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 3501 11065 3510 11097 3533 11082 3526 11039 TIME...MOT...LOC 2139Z 261DEG 11KT 3516 11087 41
Special weather statement, Oct 21, 3:57 PM MDT, 9 minutes before
Special Weather Statement National Weather Service Flagstaff AZ 257 PM MST SUN OCT 21 2018 AZZ007-012-212245- Little Colorado River Valley in Coconino County-Coconino Plateau- 257 PM MST SUN OCT 21 2018 ...SIGNIFICANT WEATHER ADVISORY FOR COCONINO COUNTY UNTIL 345 PM MST... At 255 PM MST, Doppler radar was tracking a strong thunderstorm 14 miles southeast of Desert View at Grand Canyon, moving northeast at 20 mph. This storm to affect highway 89 between milemarkers 475 and 490 around 330 PM MST (430 PM MDT). Nickel size hail and winds in excess of 40 mph will be possible with this storm. This storm will remain over mainly rural areas OF Coconino County. 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 3592 11157 3596 11165 3614 11139 3602 11130 TIME...MOT...LOC 2155Z 234DEG 16KT 3595 11159 41
The office that day
Everything else NWS Flagstaff, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 21, 6:43 AM MDT | Special Weather Statement | FGZ | Yavapai | 47 min |
| Oct 21, 7:39 AM MDT | Special Weather Statement | FGZ | 51 min | |
| Oct 21, 8:27 AM MDT | Special Weather Statement | FGZ | 48 min | |
| Oct 21, 9:19 AM MDT | Special Weather Statement | FGZ | 41 min | |
| Oct 21, 1:44 PM MDT | Areal Flood Advisory | FGZ | Apache | 3 hr |
| Oct 21, 2:01 PM MDT | Severe Thunderstorm Warning | FGZ | Coconino | 14 min |
| Oct 21, 3:07 PM MDT | Tornado Warning | FGZ | Coconino | 23 min |
| Oct 21, 3:40 PM MDT | Special Weather Statement | FGZ | Navajo | 50 min |
| Oct 21, 3:57 PM MDT | Special Weather Statement | FGZ | Coconino | 48 min |
| Oct 21, 4:44 PM MDT | Flash Flood Warning | FGZ | Navajo | 3 hr |
| Oct 21, 5:32 PM MDT | Severe Thunderstorm Warning | FGZ | Coconino | 28 min |
| Oct 21, 5:55 PM MDT | Severe Thunderstorm Warning | FGZ | Coconino | 35 min |
Nearby
Severe Thunderstorm Warnings in Arizona, 2018Every severe thunderstorm warning in 2018
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.