Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 29, NWS Flagstaff, AZ

July 11, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 11, 2021, 3:49 PM MST for Yavapai County, Arizona. It was in force for 41 min. 5 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 11, 2021, 3:49 PM MST (22:49 UTC)
Expired: Jul 11, 2021, 4:30 PM MST
In force: 41 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 116 km from the middle of the area, began a volume at 22:50 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.

What was reported inside it

Time	Report	Where	Remark
Jul 11, 3:52 PM MST	HAIL 1.25	4 S Prescott Airport, AZ
Jul 11, 3:55 PM MST	HAIL 1.25	4 Ssw Prescott Airport, AZ	HALF DOLLAR SIZE HAIL MEASURED BY SPOTTER Y421.
Jul 11, 3:59 PM MST	HAIL 1	4 Sw Prescott Airport, AZ
Jul 11, 4:10 PM MST	HAIL 0.5	6 Nne Iron Springs, AZ	TRAINED SPOTTER Y196 REPORTS HAIL AROUND HALF INCH IN SIZE.
Jul 11, 4:14 PM MST	TSTM WND GST 83	1 Ene Prescott Airport, AZ	ASOS STATION KPRC PRESCOTT AIRPORT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 10.8 hours before the alert went out and 89 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: 197 J/kg
Mixed-layer CIN: -303 J/kg
Mixed-layer LCL: 2378 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 126 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

086 
WUUS55 KFGZ 112249
SVRFGZ
AZC025-112330-
/O.NEW.KFGZ.SV.W.0029.210711T2249Z-210711T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
349 PM MST Sun Jul 11 2021

The National Weather Service in Flagstaff has issued a

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

* Until 430 PM MST.

* At 348 PM MST, a severe thunderstorm was located over Downtown
  Prescott, or near Prescott Valley, moving southwest at 55 mph.

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

  SOURCE...Trained weather spotters.

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

* Locations impacted include...
  Prescott Valley, Prescott, Yavapai Campground and Prescott Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Watch for heavy rainfall leading to ponding and minor flooding on 
area roadways.

&&

LAT...LON 3469 11239 3461 11234 3454 11254 3468 11263
TIME...MOT...LOC 2248Z 038DEG 49KT 3458 11246 

HAIL...1.00IN
WIND...60MPH
 
$$

NL

2 follow-up statements

085 
WWUS55 KFGZ 112258
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
358 PM MST Sun Jul 11 2021

AZC025-112330-
/O.CON.KFGZ.SV.W.0029.000000T0000Z-210711T2330Z/
Yavapai-
358 PM MST Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM MST
FOR YAVAPAI COUNTY...

At 357 PM MST, a severe thunderstorm was located near Ponderosa Park,
or 11 miles southwest of Prescott Valley, moving southwest at 55 mph.

HAZARD...60 mph wind gusts and half dollar size hail.

SOURCE...Trained weather spotters.

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

Locations impacted include...
Prescott Valley, Prescott, Yavapai Campground and Prescott Airport. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Watch for heavy rainfall leading to ponding and minor flooding on 
area roadways.

&&

LAT...LON 3469 11239 3461 11234 3454 11254 3468 11263
TIME...MOT...LOC 2257Z 038DEG 49KT 3448 11256 

HAIL...1.25IN
WIND...60MPH
 
$$

NL

889 
WWUS55 KFGZ 112302
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
402 PM MST Sun Jul 11 2021

AZC025-112330-
/O.CON.KFGZ.SV.W.0029.000000T0000Z-210711T2330Z/
Yavapai-
402 PM MST Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM MST
FOR YAVAPAI COUNTY...

At 401 PM MST, a severe thunderstorm was located near Yavapai
Campground, or near Prescott Valley, moving west at 10 mph.

HAZARD...60 mph wind gusts and half dollar size hail.

SOURCE...Trained weather spotters.

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

Locations impacted include...
Prescott, Yavapai Campground and Prescott Airport. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Watch for heavy rainfall leading to ponding and minor flooding on 
area roadways.

&&

LAT...LON 3469 11240 3460 11236 3454 11254 3468 11263
TIME...MOT...LOC 2301Z 094DEG 9KT 3461 11248 

HAIL...1.25IN
WIND...60MPH
 
$$

NL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 10, 5:09 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Gila, Yavapai	51 min
Jul 10, 5:16 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Coconino, Gila, Navajo	44 min
Jul 10, 5:56 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	49 min
Jul 10, 6:23 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila, Navajo	3 hr
Jul 10, 6:44 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	35 min
Jul 11, 3:22 PM MST	Special Weather Statement	FGZ	Yavapai	23 min
Jul 11, 3:35 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	40 min
Jul 11, 4:25 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	35 min
Jul 11, 4:46 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	29 min
Jul 11, 4:58 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	11 min

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.