Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 111, NWS Phoenix, AZ

September 29, 2021Pinal County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Sep 29, 2021, 10:27 PM MST for Pinal County, Arizona. It was in force for 48 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
Sep 29, 2021, 10:27 PM MST (05:27 UTC)
Expired
Sep 29, 2021, 11:15 PM MST
In force
48 min
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Pinal County, AZ

The radar

The Phoenix radar (KIWA), 44 km from the middle of the area, began a volume at 05:30 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

Tuscon, AZ (KTUS), launched 00:00Z, 5.5 hours before the alert went out and 116 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, Tuscon, AZ at 00:00Z on 2021-09-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 314 joules per kilogram.LCLLFCEL10008507005003002001001 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, Tuscon, AZ at 00:00Z on 2021-09-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.193958Sfc1 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
314 J/kg
Mixed-layer CIN
-91 J/kg
Mixed-layer LCL
2898 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

824 
WUUS55 KPSR 300527
SVRPSR
AZC021-300615-
/O.NEW.KPSR.SV.W.0111.210930T0527Z-210930T0615Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
1027 PM MST Wed Sep 29 2021

The National Weather Service in Phoenix has issued a

* Severe Thunderstorm Warning for...
  Pinal County in southeastern Arizona...

* Until 1115 PM MST.

* At 1027 PM MST, a severe thunderstorm was located near Casa Grande,
  moving east 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...
  Casa Grande, La Palma, Arizola, Randolph, Blackwater, Sacaton and
  Stanfield.

This includes the following highways...
AZ Interstate 10 between mile markers 180 and 200.
AZ Interstate 8 between mile markers 166 and 178.
AZ Route 87 between mile markers 124 and 128, and between mile
markers 138 and 150.

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 3296 11201 3314 11169 3288 11148 3283 11154
      3278 11184 3279 11187
TIME...MOT...LOC 0527Z 252DEG 13KT 3289 11181 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

SDB
2 follow-up statements
271 
WWUS55 KPSR 300553
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
1053 PM MST Wed Sep 29 2021

AZC021-300615-
/O.CON.KPSR.SV.W.0111.000000T0000Z-210930T0615Z/
Pinal AZ-
1053 PM MST Wed Sep 29 2021

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

At 1052 PM MST, a severe thunderstorm was located over Arizola, or
near Casa Grande, moving east 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...
Casa Grande, La Palma, Arizola, Randolph and Blackwater. 

This includes the following highways...
AZ Interstate 10 between mile markers 184 and 200.
AZ Interstate 8 between mile markers 168 and 178.
AZ Route 87 between mile markers 124 and 128, and between mile
markers 138 and 146.

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 3278 11184 3294 11193 3309 11165 3288 11148
      3283 11154
TIME...MOT...LOC 0552Z 266DEG 12KT 3284 11173 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

SDB
324 
WWUS55 KPSR 300610
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
1110 PM MST Wed Sep 29 2021

AZC021-300620-
/O.EXP.KPSR.SV.W.0111.000000T0000Z-210930T0615Z/
Pinal AZ-
1110 PM MST Wed Sep 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR PINAL COUNTY WILL EXPIRE AT
1115 PM MST...
                
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 will be allowed to expire.  However small
hail, gusty winds and heavy rain are still possible with this
thunderstorm.

LAT...LON 3278 11184 3294 11193 3309 11165 3288 11148
      3283 11154
TIME...MOT...LOC 0610Z 252DEG 13KT 3286 11167 

$$

SDB

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 29, 5:09 PM MSTSpecial Weather StatementPSRYuma51 min
Sep 29, 6:34 PM MSTSpecial Weather StatementPSR26 min
Sep 29, 7:36 PM MSTSpecial Weather StatementPSRLa Paz39 min
Sep 29, 8:00 PM MSTAreal Flood AdvisoryPSRYuma3 hr
Sep 29, 8:20 PM MSTSpecial Weather StatementPSRLa Paz40 min
Sep 29, 10:10 PM MSTSpecial Weather StatementPSRPinal35 min
Sep 29, 11:02 PM MSTAreal Flood AdvisoryPSRPinal3 hr
Sep 29, 11:13 PM MSTSpecial Weather StatementPSRPinal32 min
Sep 29, 11:45 PM MSTSpecial Weather StatementPSRPinal45 min
Sep 29, 11:55 PM MSTSevere Thunderstorm WarningPSRPinal35 min
Sep 30, 12:42 AM MSTSevere Thunderstorm WarningPSRGila, Pinal48 min
Sep 30, 1:00 AM MSTAreal Flood AdvisoryPSRMaricopa3 hr
Sep 30, 1:30 AM MSTSpecial Weather StatementPSR30 min
Sep 30, 2:47 PM MSTSpecial Weather StatementPSR43 min
Sep 30, 3:39 PM MSTAreal Flood AdvisoryPSRMaricopa8 hr
Sep 30, 4:21 PM MSTSpecial Weather StatementPSR39 min
Sep 30, 4:26 PM MSTSpecial Weather StatementPSR49 min

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.