Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 112, NWS Phoenix, AZ

September 29, 2021Pinal County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Sep 29, 2021, 11:55 PM MST for Pinal County, Arizona. It was in force for 35 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, 11:55 PM MST (06:55 UTC)
Expired: Sep 30, 2021, 12:30 AM MST
In force: 35 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 06:59 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, 6.9 hours before the alert went out and 105 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: 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.

065 
WUUS55 KPSR 300655
SVRPSR
AZC021-300730-
/O.NEW.KPSR.SV.W.0112.210930T0655Z-210930T0730Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
1155 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 1230 AM MST.

* At 1154 PM MST, a severe thunderstorm was located near Florence,
  moving northeast at 30 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...
  Florence, Coolidge Airport and Valley Farms. 

This includes AZ Route 79 between mile markers 129 and 140.
 
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.

&&

LAT...LON 3300 11130 3295 11137 3293 11142 3304 11149
      3326 11112 3317 11106
TIME...MOT...LOC 0654Z 242DEG 25KT 3304 11126 

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

$$

Iniguez

2 follow-up statements

028 
WWUS55 KPSR 300712
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
1212 AM MST Thu Sep 30 2021

AZC021-300730-
/O.CON.KPSR.SV.W.0112.000000T0000Z-210930T0730Z/
Pinal AZ-
1212 AM MST Thu Sep 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 AM MST
FOR PINAL COUNTY...

At 1211 AM MST, a severe thunderstorm was located 11 miles east of
Florence, moving northeast at 30 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.

This severe thunderstorm will remain over mainly rural areas of Pinal
County.

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.

&&

LAT...LON 3300 11130 3313 11133 3320 11121 3323 11110
      3317 11106
TIME...MOT...LOC 0711Z 233DEG 26KT 3309 11118 

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

$$

Iniguez

675 
WWUS55 KPSR 300727
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
1227 AM MST Thu Sep 30 2021

AZC021-300737-
/O.EXP.KPSR.SV.W.0112.000000T0000Z-210930T0730Z/
Pinal AZ-
1227 AM MST Thu Sep 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR PINAL COUNTY WILL EXPIRE AT
1230 AM MST...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

LAT...LON 3300 11130 3313 11133 3320 11121 3323 11110
      3317 11106
TIME...MOT...LOC 0727Z 242DEG 25KT 3314 11107 

$$

Iniguez

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 29, 5:09 PM MST	Special Weather Statement	PSR	Yuma	51 min
Sep 29, 6:34 PM MST	Special Weather Statement	PSR		26 min
Sep 29, 7:36 PM MST	Special Weather Statement	PSR	La Paz	39 min
Sep 29, 8:00 PM MST	Areal Flood Advisory	PSR	Yuma	3 hr
Sep 29, 8:20 PM MST	Special Weather Statement	PSR	La Paz	40 min
Sep 29, 10:10 PM MST	Special Weather Statement	PSR	Pinal	35 min
Sep 29, 10:27 PM MST	Severe Thunderstorm Warning	PSR	Pinal	48 min
Sep 29, 11:02 PM MST	Areal Flood Advisory	PSR	Pinal	3 hr
Sep 29, 11:13 PM MST	Special Weather Statement	PSR	Pinal	32 min
Sep 29, 11:45 PM MST	Special Weather Statement	PSR	Pinal	45 min
Sep 30, 12:42 AM MST	Severe Thunderstorm Warning	PSR	Gila, Pinal	48 min
Sep 30, 1:00 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Sep 30, 1:30 AM MST	Special Weather Statement	PSR		30 min
Sep 30, 2:47 PM MST	Special Weather Statement	PSR		43 min
Sep 30, 3:39 PM MST	Areal Flood Advisory	PSR	Maricopa	8 hr
Sep 30, 4:21 PM MST	Special Weather Statement	PSR		39 min
Sep 30, 4:26 PM MST	Special Weather Statement	PSR		49 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.