Alert archive / Wyoming / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 23, NWS Riverton, WY

July 1, 2019Fremont County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 1, 2019, 3:48 PM MDT for Fremont County, Wyoming. It was in force for 42 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
Jul 1, 2019, 3:48 PM MDT (21:48 UTC)
Expired
Jul 1, 2019, 4:30 PM MDT
In force
42 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Fremont County, WY

The radar

The Riverton/Lander radar (KRIW), 13 km from the middle of the area, began a volume at 21:50 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

Riverton, WY (KRIW), launched 12:00Z, 9.8 hours before the alert went out and 19 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, Riverton, WY at 12:00Z on 2019-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 22 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2019-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 55 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
22 J/kg
Mixed-layer CIN
-160 J/kg
Mixed-layer LCL
1225 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
55 m²/s²
0-3 km storm-relative helicity
98 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 Riverton, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 1, 12:01 PM MDT, 3 hours 47 minutes earlier.

Area forecast discussion, Jul 1, 12:01 PM MDT, 3 hours 47 minutes before
Area Forecast Discussion
National Weather Service Riverton WY
1201 PM MDT Mon Jul 1 2019

.SHORT TERM...Today and tonight

Clearing skies are quickly spreading eastward this morning. Low
clouds have also developed over portions of Natrona County. Fog
will become a possibility in this and other areas where
precipitation fell Sunday. The unseasonably high dewpoints will
also aid in this formation. Otherwise, skies will become clear
across the area late this morning. This will allow for isolated to
scattered showers to develop over the northwestern mountains,
spreading eastward across mainly northern portions through the
afternoon. An isolated embedded thunderstorm will be possible
during this time. These showers will end by sunset this evening.
Winds will also be light across much of the area today, with gusty
winds up to 25 mph occurring in the higher elevations of the
western mountains.

.LONG TERM...Tuesday through Sunday

Several shortwaves embedded within the near-zonal flow this week
will bring continued chances of showers and thunderstorms during the
afternoons. The best coverage still looks to be northern Wyoming and
over higher elevations, with southern Wyoming staying mostly dry
through the period. This will not help mitigate fire concerns across
southern Wyoming, as elevated fire conditions could return across
those areas by midweek as RHs drop back into the teens. Afternoon
temperatures will remain warm throughout the week. By Friday models
suggest that the low sitting to our northwest will finally lift
across Montana. Gusty winds are likely towards the end of the week
as the pressure gradient tightens in response to the lifting low. By
the weekend temperatures should warm slightly as stronger ridging
sets in.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1154 AM MDT Mon Jul 1 2019

Afternoon thunderstorms are beginning to fire on the higher
elevations of the Absarokas and the Wyoming range. Expect these
storms to moves east during the afternoon, and will likely
approach most airports east of the divide. Some storms may produce
variably gusty winds through the afternoon. Storms will decrease
after sunset, with mostly clear skies and lighter winds overnight.

&&

.FIRE WEATHER...

Isolated to scattered showers will develop over the western
mountains this afternoon, spreading eastward across the northern
zones. Isolated thunderstorms will also be possible. This activity
will end before sunset this evening. Otherwise, winds will be
light with gusts up to 25 mph occurring in the higher elevations
of the western zones.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...LaVoie
LONG TERM...Myers
AVIATION...Straub
FIRE WEATHER...LaVoie
Hazardous weather outlook, Jul 1, 3:02 AM MDT, 12 hours 46 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
302 AM MDT Mon Jul 1 2019

WYZ001>020-022>030-020915-
Yellowstone National Park-Absaroka Mountains-Cody Foothills-
North Big Horn Basin-Southwest Big Horn Basin-
Southeast Big Horn Basin-Owl Creek and Bridger Mountains-
Bighorn Mountains West-Bighorn Mountains Southeast-
Northeast Johnson County-Southeast Johnson County-
Teton and Gros Ventre Mountains-Jackson Hole-
Wind River Mountains West-Wind River Mountains East-
Upper Wind River Basin-Wind River Basin-Lander Foothills-
Green Mountains and Rattlesnake Range-
Natrona County Lower Elevations-Casper Mountain-Star Valley-
Salt River and Wyoming Ranges-Upper Green River Basin Foothills-
Upper Green River Basin-South Lincoln County-
Rock Springs and Green River-Flaming Gorge-East Sweetwater County-
302 AM MDT Mon Jul 1 2019

This Hazardous Weather Outlook is for Western and Central
Wyoming.

.DAY ONE...Today and Tonight.

Isolated to scattered thunderstorms over northern and northwestern
portions.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tuesday through Thursday...Afternoon and evening thunderstorms,
especially across the northern and northwestern portions. It will
be driest across southwest Wyoming.

Tuesday through Thursday...Elevated fire conditions possible over
southern Wyoming.

.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 1, 2:03 PM MDT, 1 hour 45 minutes before
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Special weather statement, Jul 1, 2:12 PM MDT, 1 hour 36 minutes before
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Special weather statement, Jul 1, 2:49 PM MDT, 59 minutes before
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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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Special weather statement, Jul 1, 3:26 PM MDT, 22 minutes before
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        Please try again in a few minutes.
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Special weather statement, Jul 1, 3:42 PM MDT, 6 minutes before
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      <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.
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Special weather statement, Jul 1, 3:45 PM MDT, 3 minutes before
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<body>
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      <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>
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The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 30, 6:06 PM MDTSpecial Weather StatementRIWJohnson84 min
Jul 1, 5:09 AM MDTSpecial Weather StatementRIW36 min
Jul 1, 5:41 AM MDTSpecial Weather StatementRIW34 min
Jul 1, 6:11 AM MDTSpecial Weather StatementRIW34 min
Jul 1, 6:40 AM MDTSpecial Weather StatementRIWPark35 min
Jul 1, 7:15 AM MDTSpecial Weather StatementRIWTeton30 min
Jul 1, 9:13 AM MDTSpecial Weather StatementRIWPark32 min
Jul 1, 11:53 AM MDTSpecial Weather StatementRIW22 min
Jul 1, 12:12 PM MDTSpecial Weather StatementRIWHot Springs33 min
Jul 1, 12:33 PM MDTSpecial Weather StatementRIWFremont27 min
Jul 1, 12:51 PM MDTSevere Thunderstorm WarningRIWJohnson39 min
Jul 1, 12:55 PM MDTSevere Thunderstorm WarningRIWHot Springs50 min
Jul 1, 1:06 PM MDTSevere Thunderstorm WarningRIWFremont39 min
Jul 1, 1:11 PM MDTTornado WarningRIWHot Springs34 min
Jul 1, 1:22 PM MDTSpecial Weather StatementRIWSublette23 min
Jul 1, 1:28 PM MDTSevere Thunderstorm WarningRIWJohnson, Natrona47 min
Jul 1, 1:41 PM MDTTornado WarningRIWHot Springs34 min
Jul 1, 1:42 PM MDTSevere Thunderstorm WarningRIWFremont, Hot Springs16 min
Jul 1, 1:51 PM MDTSpecial Weather StatementRIWSublette24 min
Jul 1, 1:57 PM MDTSevere Thunderstorm WarningRIWSublette35 min
Jul 1, 2:01 PM MDTSpecial Weather StatementRIWSublette29 min
Jul 1, 2:03 PM MDTSpecial Weather StatementRIWFremont27 min
Jul 1, 2:06 PM MDTSevere Thunderstorm WarningRIWHot Springs39 min
Jul 1, 2:11 PM MDTSevere Thunderstorm WarningRIWFremont19 min
Jul 1, 2:12 PM MDTSpecial Weather StatementRIW33 min
Jul 1, 2:32 PM MDTSevere Thunderstorm WarningRIWFremont43 min
Jul 1, 2:44 PM MDTSevere Thunderstorm WarningRIWHot Springs, Natrona, Washakie46 min
Jul 1, 2:49 PM MDTSpecial Weather StatementRIWWashakie26 min
Jul 1, 3:05 PM MDTSevere Thunderstorm WarningRIWBig Horn, Park40 min
Jul 1, 3:08 PM MDTSevere Thunderstorm WarningRIWFremont52 min
Jul 1, 3:26 PM MDTSpecial Weather StatementRIW34 min
Jul 1, 3:42 PM MDTSpecial Weather StatementRIWBig Horn33 min
Jul 1, 3:45 PM MDTSpecial Weather StatementRIWJohnson30 min
Jul 1, 3:50 PM MDTSevere Thunderstorm WarningRIWJohnson, Natrona40 min
Jul 1, 4:27 PM MDTSpecial Weather StatementRIW33 min
Jul 1, 5:41 PM MDTSpecial Weather StatementRIWNatrona49 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2019Every severe thunderstorm warning in 2019

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.