Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 25, NWS Phoenix, AZ

July 12, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Jul 12, 2021, 10:05 PM MST for Maricopa County, Arizona. It was in force for 25 min. 1 report 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 12, 2021, 10:05 PM MST (05:05 UTC)
Expired: Jul 12, 2021, 10:30 PM MST
In force: 25 min
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 49 km from the middle of the area, began a volume at 05:07 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 12, 10:18 PM MST	TSTM WND GST 60	6 Nw North Scottsdale, AZ	AND 0.5 INCH. HAIL AND NEAR ZERO VISIBILITY IN HEAVY RAIN.

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

The nearest sounding before it

Phoenix, AZ (KPSR), launched 00:00Z, 5.1 hours before the alert went out and 25 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: 523 J/kg
Mixed-layer CIN: -351 J/kg
Mixed-layer LCL: 2953 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

578 
WUUS55 KPSR 130505
SVRPSR
AZC013-130545-
/O.NEW.KPSR.SV.W.0025.210713T0505Z-210713T0545Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
1005 PM MST Mon Jul 12 2021

The National Weather Service in Phoenix has issued a

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

* Until 1045 PM MST.

* At 1005 PM MST, a severe thunderstorm was located over Desert Ridge
  Marketplace, or near Scottsdale, moving southwest at 25 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...
  Phoenix, Glendale, Scottsdale, Tempe, Peoria, El Mirage, Fountain
  Hills, Paradise Valley, Youngtown, Sun City, Sun City West, Cave
  Creek, Carefree, Papago Park and Piestewa Peak Park.

* This includes the following highways...
  AZ Interstate 10 between mile markers 145 and 150, and between mile
  markers 152 and 153.
  AZ Interstate 17 between mile markers 202 and 221.
  AZ Route 51 between mile markers 1 and 15.

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 3385 11194 3367 11169 3353 11184 3340 11199
      3364 11236
TIME...MOT...LOC 0505Z 046DEG 23KT 3369 11194 

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

SDB

1 follow-up statement

297 
WWUS55 KPSR 130530
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
1030 PM MST Mon Jul 12 2021

AZC013-130540-
/O.CAN.KPSR.SV.W.0025.000000T0000Z-210713T0545Z/
Maricopa AZ-
1030 PM MST Mon Jul 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR MARICOPA COUNTY IS
CANCELLED...
                
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 has been cancelled.  However gusty winds are
still possible with this thunderstorm.

LAT...LON 3385 11194 3367 11169 3353 11184 3340 11199
      3364 11236
TIME...MOT...LOC 0526Z 046DEG 23KT 3358 11208 

$$

SDB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 7:37 PM MST	Special Weather Statement	PSR	Gila	38 min
Jul 12, 8:17 PM MST	Severe Thunderstorm Warning	PSR	Gila, Pinal	43 min
Jul 12, 8:29 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	3 hr
Jul 12, 9:18 PM MST	Special Weather Statement	PSR		42 min
Jul 12, 9:40 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	35 min
Jul 12, 10:14 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila, Maricopa	2 hr
Jul 12, 10:28 PM MST	Special Weather Statement	PSR	Maricopa	32 min
Jul 12, 11:35 PM MST	Special Weather Statement	PSR		40 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.