Alert archive / Arizona / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 26, NWS Flagstaff, AZ

July 10, 2021Gila County, Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 10, 2021, 5:56 PM MST for Gila County, Yavapai County, Arizona. It was in force for 49 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 10, 2021, 5:56 PM MST (00:56 UTC)
Expired: Jul 10, 2021, 6:45 PM MST
In force: 49 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Gila County, AZ, Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 59 km from the middle of the area, began a volume at 00:58 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 10, 4:52 PM MST	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Phoenix, AZ (KPSR), launched 00:00Z, 0.9 hours before the alert went out and 109 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: 965 J/kg
Mixed-layer CIN: -311 J/kg
Mixed-layer LCL: 3378 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

779 
WUUS55 KFGZ 110056
SVRFGZ
AZC007-025-110145-
/O.NEW.KFGZ.SV.W.0026.210711T0056Z-210711T0145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
556 PM MST Sat Jul 10 2021

The National Weather Service in Flagstaff has issued a

* Severe Thunderstorm Warning for...
  Gila County in east central Arizona...
  Yavapai County in west central Arizona...

* Until 645 PM MST.

* At 555 PM MST, severe thunderstorms were located along a line
  extending from 7 miles southeast of Rimrock to 7 miles east of 
  Gisela to 12 miles northwest of Hilltop, moving southwest at 20 
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Payson, Star Valley, Haigler Creek, Mesa Del Caballo, Tonto
  Village, Geronimo Estates, Freedom Acres, Strawberry, East Verde
  Estates, Whispering Pines, Childs Power Plant, Rye, Oxbow Estates,
  Round Valley, Young, Flowing Springs, Gisela, Horseshoe Reservoir,
  Pine and Jakes Corner.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3376 11098 3380 11116 3401 11143 3400 11173
      3441 11206 3465 11162 3446 11155 3446 11147
      3442 11155 3441 11154 3443 11132 3410 11075
      3400 11075 3400 11055 3377 11006 3370 11016
      3383 11033 3385 11057 3365 11078 3364 11092
TIME...MOT...LOC 0055Z 036DEG 30KT 3455 11169 3413 11115 3378 11052 

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

RR

2 follow-up statements

916 
WWUS55 KFGZ 110112
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
612 PM MST Sat Jul 10 2021

AZC007-025-110145-
/O.CON.KFGZ.SV.W.0026.000000T0000Z-210711T0145Z/
Gila-Yavapai-
612 PM MST Sat Jul 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MST
FOR GILA AND YAVAPAI COUNTIES...

At 612 PM MST, severe thunderstorms were located along a line
extending from 8 miles southeast of Camp Verde to near Gisela to 11
miles northwest of Hilltop, moving southwest at 35 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...
Payson, Star Valley, Oxbow Estates, Round Valley, Young, Flowing
Springs, Mesa Del Caballo, Gisela, Horseshoe Reservoir, East Verde
Estates, Jakes Corner, Childs Power Plant, Rye, Houston Mesa
Campground, Tonto Natural Bridge State Park, Deer Creek, Rose Creek
Campground and Reynolds Creek Group Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3376 11098 3380 11116 3401 11143 3400 11173
      3435 11196 3453 11168 3442 11155 3441 11154
      3405 11081 3400 11075 3397 11057 3383 11033
      3385 11057 3365 11078 3364 11092
TIME...MOT...LOC 0112Z 036DEG 30KT 3449 11175 3407 11121 3372 11058 

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

RR

669 
WWUS55 KFGZ 110131
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
631 PM MST Sat Jul 10 2021

AZC007-025-110145-
/O.CON.KFGZ.SV.W.0026.000000T0000Z-210711T0145Z/
Gila-Yavapai-
631 PM MST Sat Jul 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MST
FOR GILA AND YAVAPAI COUNTIES...

At 630 PM MST, severe thunderstorms were located along a line
extending from 8 miles west of Childs Power Plant to near Jakes
Corner to 14 miles northeast of Claypool, moving southwest at 35 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...
Oxbow Estates, Jakes Corner, Gisela, Horseshoe Reservoir, Childs
Power Plant, Rye, Deer Creek, Rose Creek Campground and Reynolds
Creek Group Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3376 11098 3380 11116 3401 11143 3400 11173
      3431 11192 3446 11171 3436 11156 3408 11116
      3383 11089 3381 11062 3365 11078 3364 11092
TIME...MOT...LOC 0130Z 036DEG 30KT 3436 11185 3394 11131 3359 11068 

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

RR

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Flagstaff, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 10, 3:46 PM MST, 2 hours 10 minutes earlier.

Area forecast discussion, Jul 10, 3:46 PM MST, 2 hours 10 minutes before

Area Forecast Discussion
National Weather Service Flagstaff AZ
345 PM MST Sat Jul 10 202

.SYNOPSIS...Hot weather continues this weekend, with chances of
afternoon and evening showers and thunderstorms, primarily south of
the I-40 corridor. More significant moisture looks to return next
week, with greater chances for showers and thunderstorms across
much of northern and central Arizona.

&&

.DISCUSSION...Convection has fired off pretty much as expected, with
the exception of a fairly active area that formed in central Navajo
and Apache counties, that is now approaching the I-40 corridor.
Activity should diminish and head into the lower deserts this
evening, with clearing skies from the north.

Somewhat quieter on Sunday as we lose some boundary layer moisture
and remain warm aloft. This will be short-lived, as the doors are
fully open to the monsoon next week. Expect active weather next week
as we ramp into moderate/high monsoon levels. Flash flooding and
severe hail will become more common each day.

Heat peaks today, still around tomorrow, then next week will cool to
more seasonable levels.

&&

.AVIATION...For the 00Z package...Expect mainly VFR conditions
for the 24 hour TAF forecast period. Sct SHRA/TSRA and ISOLD +TSRA
producing brief MVFR along and south of the I-40 corridor through
03Z Sunday. Similar conditions redevelop again AFT 18Z-19Z Sunday.
Sfc winds 5-15kts outside of storms. Aviation discussion not updated
for TAF amendments.

&&

.FIRE WEATHER...Scattered showers and thunderstorms are expected
again on Sunday, mainly south of the I-40 corridor. Activity will
increase Monday, with lowering temperatures.

Tuesday through Thursday...Expect an active pattern, with scattered
to numerous showers and thunderstorms each day. As a result, expect
cooler temperatures and generally light winds.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

Excessive Heat Warning until 8 PM MST Saturday for AZZ037.

Excessive Heat Warning until 8 PM MST Sunday for AZZ005-006.

&&

PUBLIC...Peterson
AVIATION...Peterson
FIRE WEATHER...Peterson

For Northern Arizona weather information visit
weather.gov/flagstaff

In the hours before

Special weather statement, Jul 10, 12:36 PM MST, 5 hours 20 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
136 PM MDT Sat Jul 10 2021

AZZ011-040-102000-
Chuska Mountains and Defiance Plateau-
Northeast Plateaus and Mesas South of Hwy 264-
136 PM MDT Sat Jul 10 2021

...SIGNIFICANT WEATHER ADVISORY FOR A STRONG THUNDERSTORM OVER
APACHE COUNTY AND THE NAVAJO NATION UNTIL 200 PM MDT...

At 134 PM MDT, Doppler radar was tracking a strong thunderstorm over
Wide Ruins moving south at 20 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Wide Ruins and parts of US Hwy 191 between Wide Ruins and Chambers.

LAT...LON 3551 10957 3550 10939 3530 10935 3533 10966
TIME...MOT...LOC 1934Z 004DEG 17KT 3543 10948

NL

Local storm report, Jul 10, 1:12 PM MST, 4 hours 44 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
112 PM MST SAT JUL 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0707 PM     HAIL             1 NW HEBER-OVERGAARD    34.43N 110.58W
07/09/2021  M1.00 INCH       NAVAJO             AZ   PUBLIC

&&

Special weather statement, Jul 10, 1:57 PM MST, 3 hours 59 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
157 PM MST Sat Jul 10 2021

AZZ018-102130-
Northern Gila County-
157 PM MST Sat Jul 10 2021

...SIGNIFICANT WEATHER ADVISORY FOR A STRONG THUNDERSTORM IN GILA
COUNTY INCLUDING AREAS NEAR CANYON DAY UNTIL 230 PM MST...

At 156 PM MST, Doppler radar was tracking a strong thunderstorm near
Fort Apache and Canyon Day, or 32 miles south of Show Low, moving
west at 15 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Whiteriver, Fort Apache Reservation and Canyon Day.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3380 11029 3386 11000 3367 11000 3364 11009
TIME...MOT...LOC 2056Z 077DEG 11KT 3377 11005

NL

Special weather statement, Jul 10, 2:55 PM MST, 3 hours 1 minute before

Special Weather Statement
National Weather Service Flagstaff AZ
255 PM MST Sat Jul 10 2021

AZZ008-037-102245-
Yavapai County Valleys and Basins-Yavapai County  Mountains-
255 PM MST Sat Jul 10 2021

...SIGNIFICANT WEATHER ADVISORY FOR STRONG THUNDERSTORMS IN YAVAPAI
COUNTY UNTIL 345 PM MST...

At 254 PM MST, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles west of Paulden to near Yavapai County
Fairgrounds. Movement was west at 15 mph.

Half inch hail and wind gusts up to 50 mph will be possible with
these storms.

Locations impacted include...
Chino Valley, Prescott Valley, Prescott, Prescott Airport, Williamson
Valley, Prescott Gateway Mall, Iron Springs, Yavapai Campground,
Downtown Prescott, Ponderosa Park, Indian Hill West Prescott, Oak
Knoll Village, Lynx Lake Dam, Prescott Valley Event Center and White
Spar Campground.

LAT...LON 3482 11278 3445 11247 3461 11225 3470 11241
      3486 11256
TIME...MOT...LOC 2154Z 068DEG 15KT 3487 11258 3460 11232

NL

Local storm report, Jul 10, 5:24 PM MST, 32 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
524 PM MST SAT JUL 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     HAIL             1 NW FOREST LAKES       34.35N 110.82W
07/10/2021  E0.88 INCH       COCONINO           AZ   TRAINED SPOTTER

            TRAINED SPOTTER ESTIMATED HAIL AROUND A
            NICKEL SIZE IN DIAMETER WITH PASSING
            THUNDERSTORMS.

&&

NL

Local storm report, Jul 10, 5:26 PM MST, 30 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
526 PM MST SAT JUL 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0522 PM     HAIL             2 E CLINTS WELL         34.55N 111.28W
07/10/2021  E0.88 INCH       COCONINO           AZ   PUBLIC

            PUBLIC ESTIMATED HAIL AROUND A NICKEL SIZE
            IN DIAMETER WITH PASSING SEVERE-WARNED
            THUNDERSTORMS.

&&

NL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 10, 5:09 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Gila, Yavapai	51 min
Jul 10, 5:16 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Coconino, Gila, Navajo	44 min
Jul 10, 6:23 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila, Navajo	3 hr
Jul 10, 6:44 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	35 min
Jul 11, 3:22 PM MST	Special Weather Statement	FGZ	Yavapai	23 min
Jul 11, 3:35 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	40 min
Jul 11, 3:49 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	41 min
Jul 11, 4:25 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	35 min
Jul 11, 4:46 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	29 min
Jul 11, 4:58 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	11 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.