Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

August 30, 20215 counties in Montana

NWS Great Falls, MT issued this special weather statement at Aug 30, 2021, 7:40 PM MDT for 5 counties in Montana. It was in force for 35 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 30, 2021, 7:40 PM MDT (01:40 UTC)
Expired: Aug 30, 2021, 8:15 PM MDT
In force: 35 min
Issued by: NWS Great Falls, MT
Hail: 0.00 in
Wind: 55

Counties Cascade County, MT, Chouteau County, MT, Fergus County, MT, Judith Basin County, MT, Meagher County, MT

The radar

The Great Falls radar (KTFX), 87 km from the middle of the area, began a volume at 01:43 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

Great_falls, MT (KTFX), launched 00:00Z, 1.7 hours before the alert went out and 29 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: 111 J/kg
Mixed-layer CIN: -83 J/kg
Mixed-layer LCL: 3427 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 179 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 Great Falls, MT wrote its last area forecast discussion before this special weather statement went out at Aug 30, 5:45 PM MDT, 1 hour 55 minutes earlier.

Area forecast discussion, Aug 30, 5:45 PM MDT, 1 hour 55 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>
      <p class="small" id="detail">
        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

Local storm report, Aug 30, 5:31 PM MDT, 2 hours 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
531 PM MDT MON AUG 30 2021

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

0516 PM     TSTM WND GST     1 NE BELGRADE           45.79N 111.16W
08/30/2021  M78 MPH          GALLATIN           MT   ASOS

            GUST CAME FROM CONVECTIVE CLOUDS WITH NO
            LIGHTNING OBSERVED. KTFX/KBLX RADARS SHOWED
            ONLY 20 TO 25 DBZ ECHOES.

&&

MPJ

Special weather statement, Aug 30, 5:57 PM MDT, 1 hour 43 minutes before

Special Weather Statement
National Weather Service Great Falls MT
557 PM MDT Mon Aug 30 2021

MTZ012-050-053>055-310100-
Broadwater MT-Cascade MT-Gallatin MT-Judith Basin MT-Meagher MT-
557 PM MDT Mon Aug 30 2021

...Showers and thunderstorms will impact portions of Broadwater,
Meagher, Judith Basin, Gallatin, and Cascade Counties through 700 PM
MDT...

At 553 PM MDT, Doppler radar was tracking a band of showers and
thunderstorms across portions of central and southwestern Montana.
Movement was northeast at 45 mph.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4475 11137 4564 11135 4579 11180 4584 11166
      4657 11179 4679 11149 4720 11205 4751 11205
      4769 11099 4759 11105 4744 11076 4742 11022
      4718 10976 4670 10975 4672 11027 4618 11029
      4619 11078 4560 11080 4505 11115 4449 11111
TIME...MOT...LOC 2353Z 215DEG 37KT 4669 11133 4598 11052

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

mpj

Special weather statement, Aug 30, 7:19 PM MDT, 21 minutes before

Special Weather Statement
National Weather Service Great Falls MT
719 PM MDT Mon Aug 30 2021

MTZ044-310145-
Toole MT-
719 PM MDT Mon Aug 30 2021

...A strong thunderstorm will impact portions of central Toole County
through 745 PM MDT...

At 718 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Shelby, moving northeast at 30 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Shelby, Ferdig, Ethridge and Oilmont.

This includes the following highways...
 Interstate 15 between mile markers 363 and 381.
 Highway 2 between mile markers 266 and 279.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4850 11189 4854 11214 4858 11214 4885 11175
      4867 11144
TIME...MOT...LOC 0118Z 231DEG 29KT 4862 11187

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

JAF

Special weather statement, Aug 30, 7:40 PM MDT, 0 minutes before

Special Weather Statement
National Weather Service Great Falls MT
740 PM MDT Mon Aug 30 2021

MTZ012-013-050-051-054-310215-
Chouteau MT-Cascade MT-Fergus MT-Judith Basin MT-Meagher MT-
740 PM MDT Mon Aug 30 2021

...Strong thunderstorms will impact portions of Meagher, Judith
Basin, Fergus, Chouteau, and Cascade Counties through 815 PM MDT...

At 738 PM MDT, Doppler radar was tracking showers and thunderstorms
along a line extending from near Lewistown to 11 miles southeast of
The Knees. Movement was northeast at 45 mph.

HAZARD...Wind gusts of 50 to 55 mph. Locally heavy rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4727 10872 4676 10863 4672 11027 4618 11029
      4620 11106 4640 11106 4692 11179 4713 11179
      4720 11205 4761 11193 4770 11141 4813 11141
      4813 11083 4831 11061 4830 10985 4813 10953
      4775 10953 4781 10898 4758 10831 4732 10831
TIME...MOT...LOC 0138Z 234DEG 37KT 4704 10932 4790 11111

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

mpj

The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 30, 7:19 PM MDT	Special Weather Statement	TFX	Toole	26 min
Aug 30, 9:23 PM MDT	Special Weather Statement	TFX	Blaine	22 min
Aug 30, 9:26 PM MDT	Special Weather Statement	TFX	Cascade	34 min
Aug 30, 9:54 PM MDT	Special Weather Statement	TFX	Blaine	51 min
Aug 30, 10:05 PM MDT	Special Weather Statement	TFX	Chouteau	25 min
Aug 30, 10:12 PM MDT	Special Weather Statement	TFX	Cascade	33 min
Aug 30, 10:51 PM MDT	Special Weather Statement	TFX	Blaine	39 min
Aug 30, 11:52 PM MDT	Special Weather Statement	TFX	Blaine	23 min

Nearby

Special Weather Statements in Montana, 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.