Alert archive / Montana / Severe Thunderstorm Warnings in 2022

Severe Thunderstorm Warning 143, NWS Great Falls, MT

August 12, 2022Glacier County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 12, 2022, 3:45 PM MDT for Glacier County, Montana. It was in force for 30 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
Aug 12, 2022, 3:45 PM MDT (21:45 UTC)
Expired
Aug 12, 2022, 4:15 PM MDT
In force
30 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Glacier County, MT

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 9.8 hours before the alert went out and 276 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-pSkew-T log-p diagram, Spokane, WA at 12:00Z on 2022-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 504 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 12:00Z on 2022-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
504 J/kg
Mixed-layer CIN
-335 J/kg
Mixed-layer LCL
1847 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

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 Aug 12, 2:47 PM MDT, 58 minutes earlier.

Area forecast discussion, Aug 12, 2:47 PM MDT, 58 minutes before
Area Forecast Discussion
National Weather Service Great Falls MT
247 PM MDT Fri Aug 12 2022

.SYNOPSIS...

Scattered showers and thunderstorms are likely across Southwest
and Central Montana through late evening. Some thunderstorms could
produce locally damaging wind gusts. Overall hot and dry
conditions continue, keeping most locations in the upper 80s and
90s through next week.

&&

.DISCUSSION...

Thunderstorms continue to develop over Central Idaho this
afternoon associated with a strong southwesterly jet streak.
Modest convective instability will allow for continued
development. As developing storms move across the Continental
Divide into Central Montana, they are expected to be maintained as
elevated linear segments. Downdraft CAPE values also exceed 1000
J/Kg with deep inverted-V profiles. Precipitable water is above
the 90th percentile for this time of year. Hence, convective cores
will be capable of producing heavy precipitation aloft, but
evaporative cooling with the descending storm cores will result in
primarily a convective wind gust hazard through late this
evening. In addition to the wind hazard, efficient lightning will
maintain a high potential for new fire starts on dry and highly
receptive fuels.

Thunderstorm activity clears away to the east through the early
morning hours Saturday. Isolated to scattered thunderstorms
are expected once again on Saturday afternoon, but with less
coverage and likely further south. A weak frontal boundary passes
Saturday night, with drier air following into Sunday.

The persistent and dominant upper level ridge rebuilds into next
week. Ensemble cluster analyses indicate few differences among the
range of forecast guidance, suggesting high confidence that the
ridge will persist with continued above normal temperatures. The
change will be toward drier conditions, with lower precipitable
water and afternoon relative humidity dropping to near 10 percent
for some drier locations into next week. Fortunately in this
pattern the overall winds remain light, but it doesn't take much
for thunderstorms developing further west to drift into the
upstream side of the ridge and produce a lightning hazard. The
robust ridge shows signs of breaking down by next weekend, with
around 20 percent of the ensemble members indicating a ridge
collapse and transition to a cooler northwesterly flow.

&&

.AVIATION...
1150 AM MDT Fri Aug 11 2022 (12/18Z TAF period)

VFR conditions will prevail through early afternoon; however,
showers and thunderstorms are then expected through the evening for
most terminals. These showers, moving southwest to northeast, are
expected to produce erratic gusty winds in excess of 40 knots, and
lightning. Shower activity continues during the overnight hours for
eastern portions of Central and North-central Montana before exiting
the region early Saturday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  60  96  57  92 /  60  10  10  10
CTB  58  92  52  86 /  50  10   0   0
HLN  62  95  60  93 /  60  20  10  10
BZN  56  92  56  90 /  40  30  20  20
WYS  47  80  46  80 /  40  60  30  40
DLN  54  87  52  86 /  50  30  10  20
HVR  62  96  60  91 /  60  20  10   0
LWT  59  91  57  88 /  70  20  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

http://www.weather.gov/greatfalls

In the hours before

Special weather statement, Aug 12, 2:39 PM MDT, 1 hour 6 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, Aug 12, 3:08 PM MDT, 37 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, Aug 12, 3:09 PM MDT, 36 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, Aug 12, 3:32 PM MDT, 13 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, Aug 12, 3:35 PM MDT, 10 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.

IssuedProductOfficeCountiesLasted
Aug 11, 6:31 PM MDTSpecial Weather StatementTFXBeaverhead29 min
Aug 11, 7:23 PM MDTSpecial Weather StatementTFXBeaverhead22 min
Aug 11, 7:48 PM MDTSpecial Weather StatementTFXBeaverhead27 min
Aug 11, 8:18 PM MDTSpecial Weather StatementTFXMadison27 min
Aug 11, 8:54 PM MDTSpecial Weather StatementTFXJefferson, Madison36 min
Aug 11, 10:31 PM MDTSpecial Weather StatementTFXJefferson59 min
Aug 11, 11:25 PM MDTSpecial Weather StatementTFXLewis and Clark65 min
Aug 11, 11:57 PM MDTSpecial Weather StatementTFXCascade63 min
Aug 12, 12:04 AM MDTSpecial Weather StatementTFXBroadwater56 min
Aug 12, 12:31 AM MDTSpecial Weather StatementTFXCascade44 min
Aug 12, 1:09 AM MDTSpecial Weather StatementTFXCascade66 min
Aug 12, 3:01 AM MDTSpecial Weather StatementTFXTeton44 min
Aug 12, 3:35 AM MDTSpecial Weather StatementTFXMeagher40 min
Aug 12, 2:39 PM MDTSpecial Weather StatementTFXGlacier36 min
Aug 12, 2:51 PM MDTAreal Flood AdvisoryTFXGlacier114 min
Aug 12, 3:08 PM MDTSpecial Weather StatementTFXGlacier37 min
Aug 12, 3:09 PM MDTSpecial Weather StatementTFXGlacier36 min
Aug 12, 3:35 PM MDTSpecial Weather StatementTFXPondera40 min
Aug 12, 3:45 PM MDTAreal Flood AdvisoryTFXGlacier2 hr
Aug 12, 3:58 PM MDTAreal Flood AdvisoryTFXBeaverhead2 hr
Aug 12, 4:19 PM MDTSpecial Weather StatementTFXGlacier26 min
Aug 12, 4:22 PM MDTSpecial Weather StatementTFXPondera23 min
Aug 12, 4:41 PM MDTSpecial Weather StatementTFXToole34 min
Aug 12, 4:44 PM MDTSpecial Weather StatementTFXToole46 min
Aug 12, 4:46 PM MDTSpecial Weather StatementTFXBeaverhead44 min
Aug 12, 4:51 PM MDTSpecial Weather StatementTFXBlaine39 min
Aug 12, 5:14 PM MDTSpecial Weather StatementTFXToole46 min
Aug 12, 5:19 PM MDTSpecial Weather StatementTFXGlacier41 min
Aug 12, 5:27 PM MDTSpecial Weather StatementTFXBeaverhead33 min
Aug 12, 5:32 PM MDTSevere Thunderstorm WarningTFXGlacier28 min
Aug 12, 5:35 PM MDTSpecial Weather StatementTFXPondera40 min
Aug 12, 5:36 PM MDTSpecial Weather StatementTFXToole39 min
Aug 12, 5:41 PM MDTSpecial Weather StatementTFXTeton34 min
Aug 12, 5:52 PM MDTSpecial Weather StatementTFXGlacier23 min
Aug 12, 5:56 PM MDTSpecial Weather StatementTFXLewis and Clark34 min

Nearby

Severe Thunderstorm Warnings in Montana, 2022Every severe thunderstorm warning in 2022

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.