Alert archive / Montana / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 15, NWS Great Falls, MT

May 31, 2018Gallatin County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at May 31, 2018, 6:59 PM MDT for Gallatin County, Montana. It was in force for 14 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 31, 2018, 6:59 PM MDT (00:59 UTC)
Expired: May 31, 2018, 7:13 PM MDT
In force: 14 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Gallatin County, MT

The radar

The Billings radar (KBLX), 202 km from the middle of the area, began a volume at 00:59 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 watch it was issued in

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

Issued	Product	Office	Lasted
May 31, 1:50 PM MDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 1.0 hours before the alert went out and 218 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 641 m above ground
0-6 km bulk shear: 70 kt
0-1 km storm-relative helicity: 235 m²/s²
0-3 km storm-relative helicity: 429 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

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 Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at May 31, 6:00 PM MDT, 59 minutes earlier.

Area forecast discussion, May 31, 6:00 PM MDT, 59 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

In the hours before

Local storm report, May 31, 3:50 PM MDT, 3 hours 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
350 PM MDT THU MAY 31 2018

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

0340 PM     HAIL             3 WNW WISE RIVER        45.80N 113.01W
05/31/2018  E0.25 INCH       BEAVERHEAD         MT   TRAINED SPOTTER

            BRIEF PERIOD OF PEA SIZED HAIL. LIGHT WIND
            GUST, LITTLE RAIN.

&&

SAC

Special weather statement, May 31, 4:11 PM MDT, 2 hours 48 minutes before

Special Weather Statement
National Weather Service Great Falls MT
411 PM MDT THU MAY 31 2018

MTZ013-312245-
Chouteau-
411 PM MDT THU MAY 31 2018

...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL CHOUTEAU COUNTY...

At 411 PM MDT, a strong thunderstorm was located 15 miles east of
Fort Benton, moving north at 30 mph.

Wind gusts up to 50 mph and nickel size hail are possible with this
storm.

Locations impacted include...
Virgelle.

This includes Highway 87 between mile markers 63 and 77.

LAT...LON 4776 11022 4779 11042 4820 11042 4814 10997
TIME...MOT...LOC 2211Z 191DEG 27KT 4786 11032

KJ

Special weather statement, May 31, 4:14 PM MDT, 2 hours 45 minutes before

Special Weather Statement
National Weather Service Great Falls MT
414 PM MDT THU MAY 31 2018

MTZ014-312245-
Central and Southern Lewis and Clark-
414 PM MDT THU MAY 31 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SOUTH CENTRAL LEWIS AND
CLARK AND SOUTHWESTERN CASCADE COUNTIES...

At 414 PM MDT, radar indicated strong thunderstorms were located
along a line extending from 8 miles east of Lincoln to 17 miles
southwest of Wolf Creek to 18 miles northeast of Garrison. Movement
was northeast at 45 mph.

Wind gusts up to 50 mph and dime size hail are possible with these
storms.

Locations impacted include...
Wolf Creek, Marysville, Canyon Creek and Craig.

This includes the following highways...
 Interstate 15 between mile markers 202 and 238.
 Highway 200 between mile markers 78 and 104.
 Highway 287 between mile markers 1  and 19.

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 4732 11209 4730 11205 4720 11205 4718 11201
      4719 11198 4714 11193 4676 11191 4665 11232
      4666 11241 4670 11242 4670 11253 4687 11252
      4703 11259
TIME...MOT...LOC 2214Z 222DEG 38KT 4700 11252 4691 11241 4666 11246

KJ

Local storm report, May 31, 4:40 PM MDT, 2 hours 19 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Local storm report, May 31, 5:19 PM MDT, 1 hour 40 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Special weather statement, May 31, 5:57 PM MDT, 1 hour 2 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

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

Issued	Product	Office	Counties	Lasted
May 31, 6:20 PM MDT	Severe Thunderstorm Warning	TFX	Beaverhead, Gallatin, Madison	40 min
May 31, 7:12 PM MDT	Special Weather Statement	TFX	Jefferson	33 min
May 31, 7:59 PM MDT	Special Weather Statement	TFX	Judith Basin	31 min
May 31, 11:41 PM MDT	Areal Flood Advisory	TFX	Cascade	5 hr
Jun 1, 2:01 AM MDT	Areal Flood Warning	TFX	Lewis and Clark	12 hr

Nearby

Severe Thunderstorm Warnings in Montana, 2018 Every severe thunderstorm warning in 2018

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.