Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 68, NWS Tucson, AZ

July 18, 2021Graham County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Jul 18, 2021, 3:05 PM MST for Graham County, Arizona. It was in force for 40 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 18, 2021, 3:05 PM MST (22:05 UTC)
Expired: Jul 18, 2021, 3:45 PM MST
In force: 40 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Graham County, AZ

The radar

The Tucson radar (KEMX), 133 km from the middle of the area, began a volume at 22:06 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 12:00Z, 10.1 hours before the alert went out and 121 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: 1146 J/kg
Mixed-layer CIN: -124 J/kg
Mixed-layer LCL: 1485 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

569 
WUUS55 KTWC 182205
SVRTWC
AZC009-182245-
/O.NEW.KTWC.SV.W.0068.210718T2205Z-210718T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Tucson AZ
305 PM MST Sun Jul 18 2021

The National Weather Service in Tucson has issued a

* Severe Thunderstorm Warning for...
  West central Graham County in southeastern Arizona...

* Until 345 PM MST.

* At 304 PM MST, a severe thunderstorm was located 14 miles northwest
  of Thatcher, or 16 miles west of Safford, moving northwest 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...
  Bylas and Fort Thomas. 

This includes Route 70 between mile markers 294 and 305, and between
mile markers 308 and 326.
 
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 3296 10987 3283 10995 3295 11034 3318 11016
TIME...MOT...LOC 2204Z 119DEG 15KT 3292 10998 

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

AH

2 follow-up statements

784 
WWUS55 KTWC 182223
SVSTWC

Severe Weather Statement
National Weather Service Tucson AZ
323 PM MST Sun Jul 18 2021

AZC009-182245-
/O.CON.KTWC.SV.W.0068.000000T0000Z-210718T2245Z/
Graham-
323 PM MST Sun Jul 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM MST
FOR WEST CENTRAL GRAHAM COUNTY...

At 323 PM MST, a severe thunderstorm was located 17 miles northwest
of Thatcher, or 20 miles northwest of Safford, moving northwest 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...
Bylas.

This includes Route 70 between mile markers 294 and 302, and between
mile markers 308 and 313.
 
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 3297 10989 3286 10996 3299 11031 3318 11016
TIME...MOT...LOC 2223Z 129DEG 13KT 3297 11002 

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

AH

880 
WWUS55 KTWC 182239
SVSTWC

Severe Weather Statement
National Weather Service Tucson AZ
339 PM MST Sun Jul 18 2021

AZC009-182249-
/O.EXP.KTWC.SV.W.0068.000000T0000Z-210718T2245Z/
Graham-
339 PM MST Sun Jul 18 2021

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL GRAHAM COUNTY
WILL EXPIRE AT 345 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.

LAT...LON 3297 10989 3286 10996 3299 11031 3318 11016
TIME...MOT...LOC 2239Z 133DEG 11KT 3300 11002 

$$

AH

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 6:50 PM MST	Special Weather Statement	TWC	Cochise	25 min
Jul 17, 8:04 PM MST	Special Weather Statement	TWC	Graham	41 min
Jul 17, 8:28 PM MST	Special Weather Statement	TWC	Cochise	32 min
Jul 18, 6:19 AM MST	Special Weather Statement	TWC	Santa Cruz	41 min
Jul 18, 7:55 AM MST	Areal Flood Advisory	TWC	Santa Cruz	3 hr
Jul 18, 11:57 AM MST	Areal Flood Advisory	TWC	Cochise	3 hr
Jul 18, 1:00 PM MST	Areal Flood Advisory	TWC	Graham	109 min
Jul 18, 1:28 PM MST	Flash Flood Watch	TWC	Cochise, Graham, Greenlee, Pima, Pinal, Santa Cruz	11 hr
Jul 18, 2:36 PM MST	Areal Flood Advisory	TWC	Graham	3 hr
Jul 18, 3:36 PM MST	Areal Flood Advisory	TWC	Graham	114 min
Jul 18, 4:08 PM MST	Flash Flood Warning Considerable damage threat	TWC	Greenlee	112 min
Jul 18, 4:10 PM MST	Special Weather Statement	TWC		35 min
Jul 18, 4:16 PM MST	Areal Flood Advisory	TWC	Graham, Greenlee	119 min
Jul 18, 4:21 PM MST	Areal Flood Advisory	TWC	Graham	114 min
Jul 18, 4:36 PM MST	Flash Flood Warning Considerable damage threat	TWC	Graham, Greenlee	3 hr
Jul 18, 4:45 PM MST	Areal Flood Advisory	TWC	Cochise	2 hr
Jul 18, 4:50 PM MST	Severe Thunderstorm Warning	TWC	Cochise	40 min
Jul 18, 4:58 PM MST	Flash Flood Warning Considerable damage threat	TWC	Cochise	2 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.