Alert archive / Wyoming / Flash Flood Warnings in 2023

Flash Flood Warning 3, NWS Riverton, WY

June 15, 2023Natrona County, Wyoming

NWS Riverton, WY issued this flash flood warning at Jun 15, 2023, 6:13 PM MDT for Natrona County, Wyoming. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jun 15, 2023, 6:13 PM MDT (00:13 UTC)
Expired: Jun 15, 2023, 9:15 PM MDT
In force: 3 hr
Issued by: NWS Riverton, WY
Area: Storm-based polygon
Flood severity: None

County Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 137 km from the middle of the area, began a volume at 00:16 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.

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Jun 15, 5:01 PM MDT, 1 hour 12 minutes earlier.

Area forecast discussion, Jun 15, 5:01 PM MDT, 1 hour 12 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>

Hazardous weather outlook, Jun 15, 2:32 AM MDT, 15 hours 41 minutes before

Hazardous Weather Outlook
National Weather Service Riverton WY
232 AM MDT Thu Jun 15 2023

WYZ001>020-022>030-161300-
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-
232 AM MDT Thu Jun 15 2023

...Flood Watch in effect from noon Thursday to 6 PM Friday for
portions of central and north-central WY...

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...This afternoon and tonight.

More showers and thunderstorms will develop from southwest into
central Wyoming. Moderate to heavy rain is likely to fall across
portions of central and north-central WY.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Friday...Showers and thunderstorms continuing, becoming less numerous
in the afternoon.

Saturday...Possible thunderstorms in northwestern Wyoming.

Sunday through Tuesday...Scattered afternoon and evening showers and
thunderstorms, with the best chance across the northwest mountains.
Strong southwest winds are possible Monday and Tuesday from
southwest into central Wyoming.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to provide rainfall totals over the past 24
hours to the National Weather Service.

McDonald

In the hours before

Special weather statement, Jun 15, 2:17 PM MDT, 3 hours 56 minutes before

Special Weather Statement
National Weather Service Riverton WY
217 PM MDT Thu Jun 15 2023

WYZ005-007-017-020-152045-
Owl Creek and Bridger Mountains-Wind River Basin-Southwest Big Horn
Basin-Natrona County Lower Elevations-
217 PM MDT Thu Jun 15 2023

...Strong thunderstorms will impact portions of southeastern Hot
Springs, west central Natrona and east central Fremont Counties
through 245 PM MDT...

At 216 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 9 miles northwest of Boysen State Park to 8
miles southwest of Moneta. Movement was northeast at 30 mph.

HAZARD...Winds in excess of 40 mph and half inch hail along with
         heavy rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Strong thunderstorms will be near...
  Moneta around 235 PM MDT.

Other locations in the path of these storms include Lysite and Lost
Cabin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Very heavy rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

If on or near Boysen Reservoir, get out of the water and move
indoors or inside a vehicle. Remember, lightning can strike out to
10 miles from the parent thunderstorm. If you can hear thunder, you
are close enough to be struck by lightning. Move to safe shelter
now! Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4296 10781 4341 10841 4376 10800 4324 10729
TIME...MOT...LOC 2016Z 227DEG 27KT 4341 10828 4306 10782

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

McDonald

Special weather statement, Jun 15, 2:48 PM MDT, 3 hours 25 minutes before

Special Weather Statement
National Weather Service Riverton WY
248 PM MDT Thu Jun 15 2023

WYZ005-007-008-017-020-152115-
Owl Creek and Bridger Mountains-Wind River Basin-Bighorn Mountains
West-Southwest Big Horn Basin-Natrona County Lower Elevations-
248 PM MDT Thu Jun 15 2023

...Strong thunderstorms will impact portions of southeastern Hot
Springs, northwestern Natrona, east central Fremont, and southern
Washakie Counties through 315 PM MDT...

At 246 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 14 miles northeast of Shoshoni to near Lysite
to 7 miles north of Castle Gardens. Movement was northeast at 30 mph.

HAZARD...Winds in excess of 40 mph and half inch hail along with
         heavy rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Strong thunderstorms will be near...
  Lysite around 255 PM MDT.
  Lost Cabin around 300 PM MDT.

Other locations in the path of these storms include Cottonwood Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Very heavy rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

These storms 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 4290 10761 4316 10778 4341 10804 4371 10775
      4368 10771 4364 10771 4365 10766 4349 10743
      4328 10729 4324 10730 4323 10726 4317 10722
TIME...MOT...LOC 2046Z 215DEG 25KT 4341 10794 4322 10773 4304 10762

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

McDonald

Special weather statement, Jun 15, 3:06 PM MDT, 3 hours 7 minutes before

Special Weather Statement
National Weather Service Riverton WY
306 PM MDT Thu Jun 15 2023

WYZ020-022-152130-
Casper Mountain-Natrona County Lower Elevations-
306 PM MDT Thu Jun 15 2023

...A strong thunderstorm will impact portions of south central
Natrona County through 330 PM MDT...

At 306 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Alcova, which is also 22 miles southwest of Casper,
moving east at 15 mph.

HAZARD...Winds in excess of 40 mph and half inch hail along with
         heavy rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This storm will remain over mainly rural areas of south central
Natrona County, including the following locations... Bessemer Bend
and western parts of Casper Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Conditions are favorable for the development of weak, brief funnel
clouds. This type of funnel cloud is harmless, but on rare occasions
they can briefly touch down, producing wind gusts over 50 mph. If a
funnel cloud is spotted move indoors and report your sighting to the
National Weather Service.

Very heavy rainfall is also occurring with this storm and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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.

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 4258 10639 4257 10670 4259 10671 4264 10670
      4266 10671 4269 10676 4272 10677 4274 10679
      4274 10681 4287 10651
TIME...MOT...LOC 2106Z 254DEG 13KT 4266 10671

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

McDonald

Special weather statement, Jun 15, 3:17 PM MDT, 2 hours 56 minutes before

Special Weather Statement
National Weather Service Riverton WY
317 PM MDT Thu Jun 15 2023

WYZ005-007-008-017-152145-
Owl Creek and Bridger Mountains-Wind River Basin-Bighorn Mountains
West-Southwest Big Horn Basin-
317 PM MDT Thu Jun 15 2023

...Strong thunderstorms will impact portions of southeastern Hot
Springs, northwestern Natrona, east central Fremont, and
southeastern Washakie Counties through 345 PM MDT...

At 316 PM MDT, Doppler radar was tracking strong thunderstorms 9
miles south of Cottonwood Pass, which is also 21 miles northeast of
Shoshoni, moving northeast at 15 mph.

HAZARD...Winds in excess of 30 mph and half inch hail and heavy
         rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Cottonwood Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Very heavy rainfall is also occurring with this storm and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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 4329 10740 4334 10795 4367 10786 4362 10759
      4361 10758 4362 10757 4361 10755 4361 10754
      4360 10745 4358 10746 4356 10744 4359 10741
      4357 10729
TIME...MOT...LOC 2116Z 207DEG 13KT 4342 10775

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

McDonald

Special weather statement, Jun 15, 3:31 PM MDT, 2 hours 42 minutes before

Special Weather Statement
National Weather Service Riverton WY
331 PM MDT Thu Jun 15 2023

WYZ020-022-152200-
Casper Mountain-Natrona County Lower Elevations-
331 PM MDT Thu Jun 15 2023

...A strong thunderstorm will impact portions of southeastern Natrona
County through 400 PM MDT...

At 330 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Bates Hole, which is also 14 miles southwest of
Casper, moving northeast at 20 mph.

HAZARD...Winds in excess of 30 mph and penny size hail and very
         heavy rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Southwest Casper, Mills, Red Butte, Paradise Valley. and Beartrap
Meadows County Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Conditions are favorable for the development of weak, brief funnel
clouds. This type of funnel cloud is harmless, but on rare occasions
they can briefly touch down, producing wind gusts over 50 mph. If a
funnel cloud is spotted move indoors and report your sighting to the
National Weather Service.

Very heavy rainfall is also occurring with this storm and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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.

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 4255 10645 4266 10665 4291 10647 4273 10613
TIME...MOT...LOC 2130Z 216DEG 16KT 4267 10649

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...30 MPH

McDonald

Local storm report, Jun 15, 5:17 PM MDT, 56 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 Riverton, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 15, 9:11 PM MDT	Areal Flood Advisory	RIW	Natrona	16 hr
Jun 16, 6:11 AM MDT	Areal Flood Advisory	RIW	Johnson	12 hr

Nearby

Flash Flood Warnings in Wyoming, 2023 Every flash flood warning in 2023

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.