Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 33, NWS Phoenix, AZ

July 21, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Jul 21, 2021, 10:51 PM MST for Maricopa County, Arizona. It was in force for 24 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: Jul 21, 2021, 10:51 PM MST (05:51 UTC)
Expired: Jul 21, 2021, 11:15 PM MST
In force: 24 min
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 28 km from the middle of the area, began a volume at 05:51 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

Phoenix, AZ (KPSR), launched 00:00Z, 5.9 hours before the alert went out and 29 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: 760 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 3156 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -21 m²/s²
0-3 km storm-relative helicity: 10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted.

342 
WUUS55 KPSR 220551
SVRPSR
AZC013-220615-
/O.NEW.KPSR.SV.W.0033.210722T0551Z-210722T0615Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
1051 PM MST Wed Jul 21 2021

The National Weather Service in Phoenix has issued a

* Severe Thunderstorm Warning for...
  Maricopa County in south central Arizona...

* Until 1115 PM MST.

* At 1051 PM MST, a severe thunderstorm was located over Granite Reef
  Dam, or near Fountain Hills, moving north at 10 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Fountain Hills and Granite Reef Dam. 

* This includes the following highways...
  AZ Route 87 between mile markers 184 and 194.
  AZ Route 202 near mile marker 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

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

&&

LAT...LON 3349 11162 3348 11176 3361 11179 3362 11162
TIME...MOT...LOC 0551Z 178DEG 7KT 3354 11169 

HAIL...0.75IN
WIND...60MPH
 
$$

CK

2 follow-up statements

906 
WWUS55 KPSR 220559
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
1059 PM MST Wed Jul 21 2021

AZC013-220615-
/O.CON.KPSR.SV.W.0033.000000T0000Z-210722T0615Z/
Maricopa AZ-
1059 PM MST Wed Jul 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1115 PM MST
FOR MARICOPA COUNTY...

At 1059 PM MST, a severe thunderstorm was located over Granite Reef
Dam, or near Fountain Hills, moving north at 10 mph.

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

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Fountain Hills and Granite Reef Dam. 

This includes the following highways...
AZ Route 87 between mile markers 184 and 194.
AZ Route 202 near mile marker 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

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

&&

LAT...LON 3349 11162 3348 11176 3361 11179 3362 11162
TIME...MOT...LOC 0559Z 178DEG 7KT 3355 11169 

HAIL...0.88IN
WIND...60MPH
 
$$

CK

414 
WWUS55 KPSR 220611
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
1111 PM MST Wed Jul 21 2021

AZC013-220620-
/O.EXP.KPSR.SV.W.0033.000000T0000Z-210722T0615Z/
Maricopa AZ-
1111 PM MST Wed Jul 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR MARICOPA COUNTY WILL EXPIRE AT
1115 PM MST...
    
The severe thunderstorm which prompted the warning has weakened.
Therefore, the warning will be allowed to expire. However small 
hail, gusty winds and heavy rain are still possible with this 
thunderstorm.

LAT...LON 3349 11162 3348 11176 3361 11179 3362 11162
TIME...MOT...LOC 0610Z 178DEG 7KT 3357 11169 

$$

CK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 5:37 PM MST	Special Weather Statement	PSR	Yuma	38 min
Jul 21, 5:41 PM MST	Special Weather Statement	PSR		49 min
Jul 21, 6:18 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	42 min
Jul 21, 6:20 PM MST	Special Weather Statement	PSR	Gila	40 min
Jul 21, 6:47 PM MST	Special Weather Statement	PSR		43 min
Jul 21, 6:59 PM MST	Special Weather Statement	PSR	Yuma	46 min
Jul 21, 7:06 PM MST	Areal Flood Advisory	PSR	Gila	3 hr
Jul 21, 7:10 PM MST	Special Weather Statement	PSR	La Paz	50 min
Jul 21, 7:17 PM MST	Areal Flood Advisory	PSR	Yuma	44 min
Jul 21, 7:40 PM MST	Dust Storm Warning	PSR	Yuma	35 min
Jul 21, 8:01 PM MST	Flash Flood Warning Considerable damage threat	PSR	Yuma	4 hr
Jul 21, 8:13 PM MST	Dust Storm Advisory	PSR	Yuma	47 min
Jul 21, 9:06 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	39 min
Jul 21, 10:06 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	39 min
Jul 21, 10:11 PM MST	Special Weather Statement	PSR	Pinal	49 min
Jul 21, 10:23 PM MST	Special Weather Statement	PSR	Maricopa	37 min
Jul 21, 10:25 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	16 min
Jul 21, 10:39 PM MST	Special Weather Statement	PSR		36 min
Jul 21, 11:12 PM MST	Special Weather Statement	PSR		48 min
Jul 21, 11:15 PM MST	Special Weather Statement	PSR	Pinal	45 min
Jul 22, 12:28 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Jul 22, 12:32 AM MST	Areal Flood Advisory	PSR	Maricopa	118 min
Jul 22, 3:06 PM MST	Special Weather Statement	PSR		54 min
Jul 22, 3:43 PM MST	Special Weather Statement	PSR	Maricopa	47 min
Jul 22, 3:58 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	33 min
Jul 22, 4:30 PM MST	Dust Storm Advisory	PSR	Yuma	41 min
Jul 22, 4:53 PM MST	Areal Flood Advisory	PSR	Maricopa	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.