Alert archive / Arizona / Special Weather Statements in 2021

Special Weather Statement, NWS Flagstaff, AZ

August 10, 2021

NWS Flagstaff, AZ issued this special weather statement at Aug 10, 2021, 11:35 AM MST. It was in force for 25 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 10, 2021, 11:35 AM MST (18:35 UTC)
Expired: Aug 10, 2021, 12:00 PM MST
In force: 25 min
Issued by: NWS Flagstaff, AZ
Hail: 0.50 in
Wind: 40

The radar

The Flagstaff radar (KFSX), 72 km from the middle of the area, began a volume at 18:35 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

Phoenix, AZ (KPSR), launched 12:00Z, 6.6 hours before the alert went out and 188 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: 110 J/kg
Mixed-layer CIN: -193 J/kg
Mixed-layer LCL: 1490 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 93 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 10, 9:41 AM MST, 1 hour 54 minutes earlier.

Area forecast discussion, Aug 10, 9:41 AM MST, 1 hour 54 minutes before

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  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
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  <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.
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In the hours before

Special weather statement, Aug 10, 11:35 AM MST, 0 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
1135 AM MST Tue Aug 10 2021

AZZ015-101900-
Western Mogollon Rim-
1135 AM MST Tue Aug 10 2021

...A strong thunderstorm will impact Interstate 17 near
Kachina Village through NOON MST...

At 1134 AM MST, Doppler radar was tracking a strong thunderstorm over
Kachina Village, or near Flagstaff. This storm was nearly stationary.

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...
Flagstaff, Kachina Village and Mountainaire.

This includes the following highways...
 Interstate 17 between mile markers 330 and 338.
 State Route 89A between mile markers 393 and 398.

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 3510 11160 3503 11168 3510 11177 3516 11169
TIME...MOT...LOC 1834Z 147DEG 1KT 3511 11168

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

TPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 5:19 PM MST	Special Weather Statement	FGZ		41 min
Aug 9, 6:17 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 9, 6:56 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	34 min
Aug 9, 7:27 PM MST	Special Weather Statement	FGZ		33 min
Aug 9, 7:50 PM MST	Special Weather Statement	FGZ	Gila	25 min
Aug 9, 8:44 PM MST	Special Weather Statement	FGZ	Gila	46 min
Aug 9, 9:18 PM MST	Areal Flood Advisory	FGZ	Gila, Navajo	3 hr
Aug 9, 9:32 PM MST	Special Weather Statement	FGZ	Gila	43 min
Aug 10, 11:55 AM MST	Severe Thunderstorm Warning	FGZ	Coconino	15 min
Aug 10, 12:02 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 10, 12:14 PM MST	Special Weather Statement	FGZ		31 min
Aug 10, 12:46 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 10, 12:59 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 10, 1:22 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	53 min
Aug 10, 2:22 PM MST	Special Weather Statement	FGZ	Yavapai	23 min
Aug 10, 2:26 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	32 min
Aug 10, 2:35 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	40 min
Aug 10, 2:43 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 10, 2:52 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Yavapai	38 min
Aug 10, 3:11 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 10, 3:46 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 10, 4:13 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.