Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 50, NWS Phoenix, AZ

August 11, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Aug 11, 2021, 5:03 PM MST for Maricopa County, Arizona. It was in force for 42 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 11, 2021, 5:03 PM MST (00:03 UTC)
Expired
Aug 11, 2021, 5:45 PM MST
In force
42 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), 48 km from the middle of the area, began a volume at 00:02 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, 0.1 hours before the alert went out and 16 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-pSkew-T log-p diagram, Phoenix, AZ at 00:00Z on 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1157 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phoenix, AZ at 00:00Z on 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1157 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
1687 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

232 
WUUS55 KPSR 120003
SVRPSR
AZC013-120045-
/O.NEW.KPSR.SV.W.0050.210812T0003Z-210812T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
503 PM MST Wed Aug 11 2021

The National Weather Service in Phoenix has issued a

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

* Until 545 PM MST.

* At 501 PM MST, a severe thunderstorm was located over Phoenix, and
  is nearly stationary.

  HAZARD...60 mph wind gusts. Small hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Central Phoenix, Glendale, Scottsdale, Paradise Valley, Piestewa 
  Peak Park, Metro Center Mall, Camelback Mountain, North Mountain 
  Park.

This includes the following highways...
AZ Interstate 10 between mile markers 138 and 147.
AZ Interstate 17 between mile markers 200 and 213.
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.

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

&&

LAT...LON 3345 11220 3364 11223 3367 11194 3346 11191
TIME...MOT...LOC 0001Z 261DEG 4KT 3356 11205 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

AJ
1 follow-up statement
202 
WWUS55 KPSR 120041
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
541 PM MST Wed Aug 11 2021

AZC013-120050-
/O.EXP.KPSR.SV.W.0050.000000T0000Z-210812T0045Z/
Maricopa AZ-
541 PM MST Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR MARICOPA COUNTY WILL EXPIRE AT
545 PM MST...
                
The storm which prompted the warning over portions of metropolitan 
Phoenix 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 gusty winds and heavy rain are still 
possible with this thunderstorm.

LAT...LON 3345 11220 3364 11223 3367 11194 3346 11191
TIME...MOT...LOC 0040Z 261DEG 4KT 3357 11200 

$$

AJ

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 5:14 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa3 hr
Aug 11, 5:14 PM MSTSpecial Weather StatementPSRMaricopa46 min
Aug 11, 5:30 PM MSTFlash Flood WarningPSRMaricopa2 hr
Aug 11, 5:30 PM MSTSevere Thunderstorm WarningPSRMaricopa, Pinal45 min
Aug 11, 5:39 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa3 hr
Aug 11, 5:49 PM MSTSpecial Weather StatementPSR41 min
Aug 11, 5:57 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa6 hr
Aug 11, 6:07 PM MSTDust Storm WarningPSRMaricopa, Pinal53 min
Aug 11, 6:12 PM MSTSevere Thunderstorm WarningPSRMaricopa, Pinal48 min
Aug 11, 6:19 PM MSTSevere Thunderstorm WarningPSRMaricopa41 min
Aug 11, 6:20 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Aug 11, 6:40 PM MSTFlash Flood WarningPSRMaricopa4 hr
Aug 11, 7:02 PM MSTSpecial Weather StatementPSR58 min
Aug 11, 7:11 PM MSTSpecial Weather StatementPSR64 min
Aug 11, 7:26 PM MSTFlash Flood Warning Considerable damage threatPSRLa Paz3 hr
Aug 11, 7:53 PM MSTSpecial Weather StatementPSRLa Paz37 min
Aug 12, 2:00 AM MSTSpecial Weather StatementPSR45 min
Aug 12, 2:42 AM MSTFlash Flood Warning Considerable damage threatPSRGila, Maricopa4 hr
Aug 12, 2:45 AM MSTAreal Flood AdvisoryPSRMaricopa3 hr
Aug 12, 3:34 AM MSTAreal Flood AdvisoryPSRMaricopa3 hr
Aug 12, 4:16 AM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Aug 12, 4:33 AM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Aug 12, 5:17 AM MSTFlash Flood Warning Considerable damage threatPSRMaricopa6 hr
Aug 12, 6:04 AM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Aug 12, 6:21 AM MSTAreal Flood AdvisoryPSRMaricopa46 min
Aug 12, 7:00 AM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Aug 12, 10:09 AM MSTAreal Flood WarningPSRGila8 hr
Aug 12, 10:46 AM MSTAreal Flood WarningPSRMaricopa15 hr
Aug 12, 1:30 PM MSTFlash Flood WatchPSRGila, Maricopa, Pinal5 days
Aug 12, 2:11 PM MSTSpecial Weather StatementPSRLa Paz34 min
Aug 12, 2:30 PM MSTAreal Flood AdvisoryPSRMaricopa3 hr
Aug 12, 2:45 PM MSTAreal Flood AdvisoryPSRLa Paz3 hr
Aug 12, 2:54 PM MSTFlash Flood Warning Considerable damage threatPSRLa Paz, Maricopa4 hr
Aug 12, 3:11 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa5 hr
Aug 12, 3:34 PM MSTSpecial Weather StatementPSR41 min
Aug 12, 4:14 PM MSTAreal Flood AdvisoryPSRMaricopa, Yuma3 hr

Nearby

Severe Thunderstorm Warnings in Arizona, 2021Every 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.