Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 112, NWS Flagstaff, AZ

August 15, 2021Apache County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 15, 2021, 1:22 PM MST for Apache County, Arizona. It was in force for 38 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 15, 2021, 1:22 PM MST (20:22 UTC)
Expired
Aug 15, 2021, 2:00 PM MST
In force
38 min
Issued by
NWS Flagstaff, AZ
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

County Apache County, AZ

The radar

The Flagstaff radar (KFSX), 221 km from the middle of the area, began a volume at 20:21 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, 8.4 hours before the alert went out and 241 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, Flgstf/Belemont, AZ at 12:00Z on 2021-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 9 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2021-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
9 J/kg
Mixed-layer CIN
-172 J/kg
Mixed-layer LCL
2026 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

947 
WUUS55 KFGZ 152022
SVRFGZ
AZC001-152100-
/O.NEW.KFGZ.SV.W.0112.210815T2022Z-210815T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
222 PM MDT Sun Aug 15 2021

The National Weather Service in Flagstaff has issued a

* Severe Thunderstorm Warning for...
  Apache County in northeastern Arizona...

* Until 300 PM MDT.

* At 222 PM MDT, a severe thunderstorm was located 7 miles west of
  Window Rock, or 28 miles northwest of Gallup, moving southwest at 5
  mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

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

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 3578 10918 3574 10907 3550 10922 3574 10938
TIME...MOT...LOC 2022Z 041DEG 5KT 3569 10920 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

RR
2 follow-up statements
289 
WWUS55 KFGZ 152039
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
239 PM MDT Sun Aug 15 2021

AZC001-152100-
/O.CON.KFGZ.SV.W.0112.000000T0000Z-210815T2100Z/
Apache-
239 PM MDT Sun Aug 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM MDT
FOR APACHE COUNTY...

At 239 PM MDT, a severe thunderstorm was located 8 miles west of
Window Rock, or 29 miles west of Gallup, moving southwest at 5 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

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

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 3578 10918 3574 10907 3550 10922 3574 10938
TIME...MOT...LOC 2039Z 041DEG 5KT 3567 10922 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

RR
149 
WWUS55 KFGZ 152051
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
251 PM MDT Sun Aug 15 2021

AZC001-152101-
/O.EXP.KFGZ.SV.W.0112.000000T0000Z-210815T2100Z/
Apache-
251 PM MDT Sun Aug 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR APACHE COUNTY WILL EXPIRE AT
300 PM MDT...
                
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 heavy rain
is still possible with this thunderstorm.

LAT...LON 3578 10918 3574 10907 3550 10922 3574 10938
TIME...MOT...LOC 2051Z 041DEG 5KT 3566 10923 

$$

RR

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 15, 12:37 PM MSTSpecial Weather StatementFGZ23 min
Aug 15, 12:52 PM MSTSevere Thunderstorm WarningFGZCoconino38 min
Aug 15, 1:43 PM MSTSevere Thunderstorm WarningFGZCoconino, Yavapai36 min
Aug 15, 2:17 PM MSTSevere Thunderstorm WarningFGZCoconino43 min
Aug 15, 2:33 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino, Yavapai3 hr
Aug 15, 2:42 PM MSTSevere Thunderstorm WarningFGZYavapai48 min
Aug 15, 3:36 PM MSTSevere Thunderstorm WarningFGZYavapai39 min
Aug 15, 3:49 PM MSTSevere Thunderstorm WarningFGZCoconino, Navajo26 min
Aug 15, 3:52 PM MSTSevere Thunderstorm WarningFGZNavajo23 min
Aug 15, 4:49 PM MSTSevere Thunderstorm WarningFGZApache41 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.