Alert archive / Arizona / Special Weather Statements in 2021

Special Weather Statement, NWS Flagstaff, AZ

August 11, 2021

NWS Flagstaff, AZ issued this special weather statement at Aug 11, 2021, 3:11 PM MST. It was in force for 34 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 11, 2021, 3:11 PM MST (22:11 UTC)
Expired: Aug 11, 2021, 3:45 PM MST
In force: 34 min
Issued by: NWS Flagstaff, AZ
Hail: 0.50 in
Wind: 40

The radar

The Flagstaff radar (KFSX), 137 km from the middle of the area, began a volume at 22:11 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, 10.2 hours before the alert went out and 54 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: 82 J/kg
Mixed-layer CIN: -165 J/kg
Mixed-layer LCL: 1265 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 153 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Aug 11, 9:15 AM MST, 5 hours 56 minutes earlier.

Area forecast discussion, Aug 11, 9:15 AM MST, 5 hours 56 minutes before

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<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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In the hours before

Special weather statement, Aug 11, 2:25 PM MST, 46 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
225 PM MST Wed Aug 11 2021

AZZ007-015-112200-
Western Mogollon Rim-Coconino Plateau-
225 PM MST Wed Aug 11 2021

...Strong thunderstorm will impact portions of Coconino County near
Williams through 300 PM MST...

At 224 PM MST, Doppler radar was tracking a strong thunderstorm near
Williams, or 30 miles west of Flagstaff, moving northwest at 10 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Williams, Dogtown Lake Campground and Kaibab Lake Campground.

This includes the following highways...
 Business Interstate 40 between mile markers 163 and 165.
 Interstate 40 between mile markers 161 and 170.
 State Route 64 between mile markers 186 and 199.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

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 3535 11201 3520 11211 3529 11242 3551 11225
TIME...MOT...LOC 2124Z 118DEG 9KT 3531 11215

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Humphreys

Special weather statement, Aug 11, 3:11 PM MST, 0 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
311 PM MST Wed Aug 11 2021

AZZ007-008-015-112245-
Western Mogollon Rim-Coconino Plateau-Yavapai County  Mountains-
311 PM MST Wed Aug 11 2021

...A strong thunderstorm will impact portions of Yavapai and Coconino
Counties near Ash Fork through 345 PM MST...

At 310 PM MST, Doppler radar was tracking a strong thunderstorm 8
miles northeast of Ash Fork, or 37 miles north of Chino Valley,
moving west at 20 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Ash Fork.

This includes the following highways...
 Business Interstate 40 near mile marker 146.
 Interstate 40 between mile markers 140 and 158.
 State Route 89 between mile markers 362 and 363.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3540 11225 3522 11226 3518 11258 3541 11260
TIME...MOT...LOC 2210Z 084DEG 19KT 3530 11237

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Humphreys

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 9:30 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 11, 1:38 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 11, 1:48 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 11, 2:25 PM MST	Special Weather Statement	FGZ		35 min
Aug 11, 2:49 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache	3 hr
Aug 11, 4:24 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr

Nearby

Special Weather Statements in Arizona, 2021 Every special weather statement 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.