Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 28, NWS Flagstaff, AZ

July 11, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 11, 2021, 3:35 PM MST for Yavapai County, Arizona. It was in force for 40 min. 7 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, 3:35 PM MST (22:35 UTC)
Expired: Jul 11, 2021, 4:15 PM MST
In force: 40 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), 103 km from the middle of the area, began a volume at 22:39 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, 3:38 PM MST	HAIL 0.89	Dewey-Humboldt, AZ	MIX OF DIME AND NICKEL SIZED HAIL.
Jul 11, 3:43 PM MST	HAIL 0.88	1 S Prescott Valley, AZ
Jul 11, 3:48 PM MST	HAIL 1	2 Wsw Dewey-Humboldt, AZ
Jul 11, 3:49 PM MST	HAIL 1	4 Ssw Prescott Valley, AZ
Jul 11, 4:04 PM MST	HAIL 1.25	5 Sw Prescott Valley, AZ	TRAINED SPOTTER Y532 REPORTS HAIL UP TO 1.25 INCHES IN DIAMETER.
Jul 11, 4:16 PM MST	TSTM WND GST 60	2 Sw Prescott Valley, AZ	WIND GUSTS FROM A PASSING SEVERE THUNDERSTORM ESTIMATED AROUND 60 MPH.
Jul 11, 4:16 PM MST	HAIL 1	2 Sw Prescott Valley, AZ	TRAINED SPOTTER REPORTED HAIL ESTIMATED AROUND A QUARTER IN SIZE.

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, 10.6 hours before the alert went out and 92 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.

428 
WUUS55 KFGZ 112235
SVRFGZ
AZC025-112315-
/O.NEW.KFGZ.SV.W.0028.210711T2235Z-210711T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
335 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 415 PM MST.

* At 334 PM MST, a severe thunderstorm was located near
  Dewey-humboldt, or 7 miles southeast of Prescott Valley, moving
  southwest at 15 mph.

  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...
  Prescott Valley, Prescott, Dewey-humboldt, Groom Creek Subdivision,
  Walker, Poland Junction, Prescott Gateway Mall, Downtown Prescott,
  Indian Hill West Prescott, Oak Knoll Village, Lynx Lake Dam,
  Prescott Valley Event Center, Upper Wolf Creek Group Campground and
  White Spar Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Heavy rainfall is also occurring with this storm and could result in
ponding on area roadways.

&&

LAT...LON 3463 11229 3450 11217 3431 11233 3455 11254
TIME...MOT...LOC 2234Z 038DEG 12KT 3451 11231 

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

NL

3 follow-up statements

587 
WWUS55 KFGZ 112250
SVSFGZ

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

AZC025-112315-
/O.CON.KFGZ.SV.W.0028.000000T0000Z-210711T2315Z/
Yavapai-
350 PM MST Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM MST
FOR YAVAPAI COUNTY...

At 350 PM MST, a severe thunderstorm was located over Walker, or 8
miles south of Prescott Valley, moving southwest at 15 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, Dewey-humboldt, Groom Creek Subdivision,
Walker, Poland Junction, Prescott Gateway Mall, Downtown Prescott,
Indian Hill West Prescott, Oak Knoll Village, Lynx Lake Dam, Prescott
Valley Event Center, Upper Wolf Creek Group Campground and White Spar
Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Very heavy rainfall is occurring with this storm, and may lead to 
flooding on roads. Do not drive your vehicle through flooded 
roadways.

&&

LAT...LON 3463 11229 3450 11217 3431 11233 3455 11254
TIME...MOT...LOC 2250Z 038DEG 12KT 3447 11235 

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

NL

903 
WWUS55 KFGZ 112257
SVSFGZ

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

AZC025-112315-
/O.CON.KFGZ.SV.W.0028.000000T0000Z-210711T2315Z/
Yavapai-
357 PM MST Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM MST
FOR YAVAPAI COUNTY...

At 356 PM MST, a severe thunderstorm was located over Walker, or 8
miles south of Prescott Valley, moving southwest at 15 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, Dewey-humboldt, Groom Creek Subdivision,
Walker, Prescott Gateway Mall, Downtown Prescott, Indian Hill West
Prescott, Oak Knoll Village, Lynx Lake Dam, Prescott Valley Event
Center, Upper Wolf Creek Group Campground, White Spar Campground and
Lower Wolf Creek Campground.

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 3463 11229 3454 11221 3442 11243 3455 11254
TIME...MOT...LOC 2256Z 038DEG 12KT 3446 11236 

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

NL

311 
WWUS55 KFGZ 112305
SVSFGZ

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

AZC025-112315-
/O.CON.KFGZ.SV.W.0028.000000T0000Z-210711T2315Z/
Yavapai-
405 PM MST Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM MST
FOR YAVAPAI COUNTY...

At 404 PM MST, a severe thunderstorm was located over Walker, or 9
miles south of Prescott Valley, moving southwest at 15 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, Downtown Prescott, Indian Hill West
Prescott, Oak Knoll Village, Prescott Gateway Mall, Prescott Valley
Event Center, White Spar Campground and Lynx Lake Dam.

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 3462 11233 3453 11230 3447 11247 3455 11254
TIME...MOT...LOC 2304Z 038DEG 12KT 3444 11238 

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, 3:49 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	41 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.