Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 98, NWS Flagstaff, AZ

August 10, 2021Coconino County, Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 10, 2021, 2:52 PM MST for Coconino County, Yavapai County, Arizona. It was in force for 38 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 10, 2021, 2:52 PM MST (21:52 UTC)
Expired: Aug 10, 2021, 3:30 PM MST
In force: 38 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Coconino County, AZ, Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 163 km from the middle of the area, began a volume at 21:55 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, 9.9 hours before the alert went out and 90 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: 609 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 962 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

046 
WUUS55 KFGZ 102152
SVRFGZ
AZC005-025-102230-
/O.NEW.KFGZ.SV.W.0098.210810T2152Z-210810T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
252 PM MST Tue Aug 10 2021

The National Weather Service in Flagstaff has issued a

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

* Until 330 PM MST.

* At 250 PM MST, a severe thunderstorm was located near Seligman, or
  41 miles northwest of Chino Valley, 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...
  Seligman, including I-40.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3507 11276 3527 11302 3546 11284 3526 11260
TIME...MOT...LOC 2150Z 226DEG 0KT 3528 11281 

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

$$

Humphreys

1 follow-up statement

832 
WWUS55 KFGZ 102221
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
321 PM MST Tue Aug 10 2021

AZC005-025-102231-
/O.EXP.KFGZ.SV.W.0098.000000T0000Z-210810T2230Z/
Yavapai-Coconino-
321 PM MST Tue Aug 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR YAVAPAI AND COCONINO COUNTIES
WILL EXPIRE AT 330 PM MST...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with this thunderstorm.

LAT...LON 3507 11276 3527 11302 3546 11284 3526 11260
TIME...MOT...LOC 2221Z 226DEG 0KT 3528 11281 

$$

Humphreys

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 5:19 PM MST	Special Weather Statement	FGZ		41 min
Aug 9, 6:17 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 9, 6:56 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	34 min
Aug 9, 7:27 PM MST	Special Weather Statement	FGZ		33 min
Aug 9, 7:50 PM MST	Special Weather Statement	FGZ	Gila	25 min
Aug 9, 8:44 PM MST	Special Weather Statement	FGZ	Gila	46 min
Aug 9, 9:18 PM MST	Areal Flood Advisory	FGZ	Gila, Navajo	3 hr
Aug 9, 9:32 PM MST	Special Weather Statement	FGZ	Gila	43 min
Aug 10, 11:35 AM MST	Special Weather Statement	FGZ		25 min
Aug 10, 11:55 AM MST	Severe Thunderstorm Warning	FGZ	Coconino	15 min
Aug 10, 12:02 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 10, 12:14 PM MST	Special Weather Statement	FGZ		31 min
Aug 10, 12:46 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 10, 12:59 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 10, 1:22 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	53 min
Aug 10, 2:22 PM MST	Special Weather Statement	FGZ	Yavapai	23 min
Aug 10, 2:26 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	32 min
Aug 10, 2:35 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	40 min
Aug 10, 2:43 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 10, 3:11 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 10, 3:46 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 10, 4:13 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.