Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 6, NWS Flagstaff, AZ

June 29, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jun 29, 2021, 3:39 PM MST for Coconino County, Arizona. It was in force for 36 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: Jun 29, 2021, 3:39 PM MST (22:39 UTC)
Expired: Jun 29, 2021, 4:15 PM MST
In force: 36 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Coconino County, AZ

The radar

The Cedar City radar (KICX), 152 km from the middle of the area, began a volume at 22:40 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 10.7 hours before the alert went out and 190 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: 225 J/kg
Mixed-layer CIN: -162 J/kg
Mixed-layer LCL: 1570 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -75 m²/s²
0-3 km storm-relative helicity: -28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

563 
WUUS55 KFGZ 292239
SVRFGZ
AZC005-292315-
/O.NEW.KFGZ.SV.W.0006.210629T2239Z-210629T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
339 PM MST Tue Jun 29 2021

The National Weather Service in Flagstaff has issued a

* Severe Thunderstorm Warning for...
  Coconino County in north central Arizona...

* Until 415 PM MST/515 PM MDT/.

* At 338 PM MST/438 PM MDT/, severe thunderstorms were located along 
  a line near Lake Powell and Wahweap Boat Ramp, moving south at 15 
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Page, Big Five, LeChee, Marble Canyon, Lees Ferry, Antelope Canyon
  Near Sr 98, Wahweap, Antelope Creek Basin, Lake Powell and
  Waterholes Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

If on or near Lake Powell, get away from the water and move indoors 
or inside a vehicle. Remember, lightning can strike out to 15 miles 
from the parent thunderstorm. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now!  Do not 
be caught on the water in a thunderstorm.

&&

LAT...LON 3700 11110 3676 11115 3677 11182 3700 11174
TIME...MOT...LOC 2238Z 019DEG 11KT 3694 11125 3695 11188 

HAIL...<.75IN
WIND...60MPH
 
$$

ET

1 follow-up statement

564 
WWUS55 KFGZ 292308
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
408 PM MST Tue Jun 29 2021

AZC005-292318-
/O.EXP.KFGZ.SV.W.0006.000000T0000Z-210629T2315Z/
Coconino-
408 PM MST Tue Jun 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR COCONINO COUNTY WILL EXPIRE AT
415 PM MST/515 PM MDT/...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

LAT...LON 3700 11110 3676 11115 3677 11182 3700 11174
TIME...MOT...LOC 2308Z 019DEG 11KT 3686 11128 3687 11191 

$$

ET

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 29, 11:34 AM MST	Severe Thunderstorm Warning	FGZ	Coconino	26 min
Jun 29, 11:56 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Jun 29, 1:05 PM MST	Areal Flood Advisory	FGZ	Coconino, Yavapai	3 hr
Jun 29, 1:58 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	32 min
Jun 29, 2:24 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	3 hr
Jun 29, 3:03 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	42 min
Jun 29, 3:49 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jun 29, 4:07 PM MST	Special Weather Statement	FGZ	Gila	23 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.