Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 161, NWS Flagstaff, AZ

August 17, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 17, 2021, 1:28 PM MST for Coconino County, Arizona. It was in force for 47 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 17, 2021, 1:28 PM MST (20:28 UTC)
Expired: Aug 17, 2021, 2:15 PM MST
In force: 47 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 30 km from the middle of the area, began a volume at 20:27 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, 8.5 hours before the alert went out and 69 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 984 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 829 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 135 m²/s²
0-3 km storm-relative helicity: 154 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.8

Open this sounding in Storm Lab

The text

As transmitted.

398 
WUUS55 KFGZ 172028
SVRFGZ
AZC005-172115-
/O.NEW.KFGZ.SV.W.0161.210817T2028Z-210817T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
128 PM MST Tue Aug 17 2021

The National Weather Service in Flagstaff has issued a

* Severe Thunderstorm Warning for...
  Coconino County in north central Arizona...

* Until 215 PM MST.

* At 127 PM MST, a severe thunderstorm was located near Tremaine
  Lake, or 30 miles southwest of Winslow, and is nearly stationary.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Tremaine Lake, Long Lake and Chavez Mountain. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3475 11128 3494 11130 3499 11112 3477 11105
TIME...MOT...LOC 2027Z 256DEG 1KT 3484 11119 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

DB

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 16, 5:04 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Navajo	3 hr
Aug 16, 6:33 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	27 min
Aug 16, 7:08 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	37 min
Aug 16, 7:37 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	23 min
Aug 16, 7:42 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	33 min
Aug 16, 7:57 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	33 min
Aug 16, 8:04 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	26 min
Aug 16, 8:21 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	24 min
Aug 16, 9:18 PM MST	Severe Thunderstorm Warning	FGZ	Gila	42 min
Aug 16, 10:01 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	29 min
Aug 16, 10:33 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	25 min
Aug 17, 12:04 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Gila, Navajo	3 hr
Aug 17, 12:15 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	60 min
Aug 17, 12:22 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	5 hr
Aug 17, 12:29 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Gila, Navajo	46 min
Aug 17, 12:41 PM MST	Flash Flood Warning EmergencyCatastrophic damage threat	FGZ	Coconino	3 hr
Aug 17, 12:59 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	46 min
Aug 17, 1:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	5 hr
Aug 17, 1:16 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	44 min
Aug 17, 1:21 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	39 min
Aug 17, 1:37 PM MST	Flash Flood Watch	FGZ	Apache, Coconino, Navajo	9 hr
Aug 17, 2:03 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	5 hr
Aug 17, 2:09 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	51 min
Aug 17, 2:15 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	45 min
Aug 17, 2:18 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	5 hr
Aug 17, 3:03 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 17, 3:42 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	33 min
Aug 17, 3:44 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 17, 4:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 17, 4:19 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	26 min
Aug 17, 4:22 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 17, 4:46 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr

Nearby

Severe Thunderstorm Warnings in Arizona, 2021 Every severe thunderstorm warning in 2021

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.