Alert archive / Montana / Special Weather Statements in 2017

Special Weather Statement, NWS Glasgow, MT

July 20, 2017Valley County, Montana

NWS Glasgow, MT issued this special weather statement at Jul 20, 2017, 8:35 AM MDT for Valley County, Montana. It was in force for 55 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 20, 2017, 8:35 AM MDT (14:35 UTC)
Expired
Jul 20, 2017, 9:30 AM MDT
In force
55 min
Issued by
NWS Glasgow, MT

County Valley County, MT

The radar

The Glasgow radar (KGGW), 50 km from the middle of the area, began a volume at 14:39 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

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 2.6 hours before the alert went out and 50 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, Glasgow Intl Airport, MT at 12:00Z on 2017-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Glasgow Intl Airport, MT at 12:00Z on 2017-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -18 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2932 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
-18 m²/s²
0-3 km storm-relative helicity
89 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 Glasgow, MT wrote its last area forecast discussion before this special weather statement went out at Jul 20, 8:14 AM MDT, 21 minutes earlier.

Area forecast discussion, Jul 20, 8:14 AM MDT, 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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Hazardous weather outlook, Jul 20, 3:21 AM MDT, 5 hours 14 minutes before
Hazardous Weather Outlook
National Weather Service Glasgow MT
321 AM MDT Thu Jul 20 2017

MTZ016>027-059>062-210930-
Central and Southeast Phillips-Central and Southern Valley-
Daniels-Sheridan-Western Roosevelt-Petroleum-Garfield-McCone-
Richland-Dawson-Prairie-Wibaux-Northern Phillips-
Southwest Phillips-Northern Valley-Eastern Roosevelt-
321 AM MDT Thu Jul 20 2017

This Hazardous Weather Outlook is for portions of northeast
Montana.

.DAY ONE...Today and Tonight

A Red Flag Warning for low relative humidity and gusty wind is in
effect for this afternoon and evening for southwest portions of
Northeast Montana.

There is the possibility of strong thunderstorms for eastern areas
of Northeast Montana this afternoon and evening. A few storms may
become severe with damaging winds and large hail.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Critical Fire Weather conditions are possible for all zones
Friday due to low relative humidity and strong northwest wind.
The winds may also produce hazardous boating conditions on Fort
Peck Lake Friday afternoon.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.

In the hours before

Special weather statement, Jul 20, 8:35 AM MDT, 0 minutes before
Special Weather Statement
National Weather Service Glasgow MT
835 AM MDT THU JUL 20 2017

MTZ016-017-059-061-201530-
Central and Southeast Phillips MT-Northern Valley MT-
Northern Phillips MT-Central and Southern Valley MT-
835 AM MDT THU JUL 20 2017

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL PHILLIPS AND
NORTHWESTERN VALLEY COUNTIES UNTIL 930 AM MDT...

At 835 AM MDT, Doppler radar was tracking a strong thunderstorm near
Saco, or 21 miles east of Malta, moving northeast at 30 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Saco and Hinsdale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4828 10741 4843 10760 4882 10690 4851 10655
TIME...MOT...LOC 1435Z 235DEG 27KT 4840 10741

HICKFORD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 3:18 AM MDTRed Flag WarningGGWGarfield, McCone, Petroleum, Phillips, Valley42 hr
Jul 20, 11:49 AM MDTSpecial Weather StatementGGWRoosevelt, Sheridan56 min
Jul 20, 1:47 PM MDTSpecial Weather StatementGGWDaniels43 min
Jul 20, 2:08 PM MDTSpecial Weather StatementGGWSheridan52 min
Jul 20, 2:14 PM MDTSevere Thunderstorm WarningGGWRichland19 min
Jul 20, 2:39 PM MDTRed Flag WarningGGWDaniels, Dawson, Garfield, McCone, Petroleum, Phillips and 6 more54 hr
Jul 20, 2:40 PM MDTLake Wind AdvisoryGGWGarfield, McCone, Petroleum, Phillips, Valley13 hr

Nearby

Special Weather Statements in Montana, 2017Every special weather statement in 2017

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.