Alert archive / Arizona / Special Weather Statements in 2021

Special Weather Statement, NWS Phoenix, AZ

July 18, 2021Pinal County, Arizona

NWS Phoenix, AZ issued this special weather statement at Jul 18, 2021, 9:16 AM MST for Pinal County, Arizona. It was in force for 44 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 18, 2021, 9:16 AM MST (16:16 UTC)
Expired: Jul 18, 2021, 10:00 AM MST
In force: 44 min
Issued by: NWS Phoenix, AZ

County Pinal County, AZ

The radar

The Phoenix radar (KIWA), 36 km from the middle of the area, began a volume at 16:16 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, 4.3 hours before the alert went out and 67 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: 453 J/kg
Mixed-layer CIN: -202 J/kg
Mixed-layer LCL: 2153 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 7 m²/s²
0-3 km storm-relative helicity: 40 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

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 Phoenix, AZ wrote its last area forecast discussion before this special weather statement went out at Jul 18, 5:55 AM MST, 3 hours 21 minutes earlier.

Area forecast discussion, Jul 18, 5:55 AM MST, 3 hours 21 minutes before

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<html lang="en">
<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.
      </p>
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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In the hours before

Special weather statement, Jul 18, 9:16 AM MST, 0 minutes before

Special Weather Statement
National Weather Service Phoenix AZ
916 AM MST Sun Jul 18 2021

AZZ552-553-555-558-181700-
Northwest Pinal County AZ-Apache Junction/Gold Canyon AZ-Superior AZ-
Pinal/Superstition Mountains AZ-
916 AM MST Sun Jul 18 2021

...SIGNIFICANT WEATHER ADVISORY FOR PINAL COUNTY UNTIL 1000 AM MST...

At 915 AM MST, Doppler radar was tracking a strong thunderstorm 10
miles south of Boyce Thompson Arboretum, or 11 miles south of
Superior, moving northwest at 15 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Florence, Superior, Florence Junction, Queen Valley and Boyce
Thompson Arboretum.

This includes the following highways...
US Highway 60 between mile markers 207 and 227.
AZ Route 79 between mile markers 136 and 150.
AZ Route 177 between mile markers 159 and 167.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3299 11132 3319 11153 3330 11144 3338 11130
      3339 11114 3318 11104
TIME...MOT...LOC 1615Z 149DEG 14KT 3313 11118

JS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 11:24 AM MST	Areal Flood Advisory	PSR	Pinal	2 hr
Jul 18, 2:04 PM MST	Special Weather Statement	PSR	Gila	26 min
Jul 18, 2:29 PM MST	Special Weather Statement	PSR	Gila	31 min
Jul 18, 4:27 PM MST	Special Weather Statement	PSR	Gila	33 min

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.