Alert archive / Wyoming / Special Weather Statements in 2021

Special Weather Statement, NWS Cheyenne, WY

September 3, 2021Laramie County, Wyoming

NWS Cheyenne, WY issued this special weather statement at Sep 3, 2021, 3:45 PM MDT for Laramie County, Wyoming. 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 outline as issued.

The facts

Issued: Sep 3, 2021, 3:45 PM MDT (21:45 UTC)
Expired: Sep 3, 2021, 4:15 PM MDT
In force: 30 min
Issued by: NWS Cheyenne, WY
Hail: 0.00 in
Wind: 40

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 3 km from the middle of the area, began a volume at 21:46 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

Denver, CO (KDNR), launched 12:00Z, 9.8 hours before the alert went out and 192 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: 39 J/kg
Mixed-layer CIN: -181 J/kg
Mixed-layer LCL: 1546 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 55 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 Cheyenne, WY wrote its last area forecast discussion before this special weather statement went out at Sep 3, 2:47 PM MDT, 58 minutes earlier.

Area forecast discussion, Sep 3, 2:47 PM MDT, 58 minutes before

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Hazardous weather outlook, Sep 3, 3:01 PM MDT, 44 minutes before

Hazardous Weather Outlook
National Weather Service Cheyenne WY
301 PM MDT Fri Sep 3 2021

NEZ002-003-019>021-054-055-095-096-WYZ101>103-106>108-116>119-
042115-
Dawes County-Box Butte County-Scotts Bluff County-Banner County-
Morrill County-Kimball County-Cheyenne County-
Northern Sioux County-Southern Sioux County-
Converse County Lower Elevations-Niobrara County-
North Laramie Range-
Central Laramie Range and Southwest Platte County-
East Platte County-Goshen County-South Laramie Range-
South Laramie Range Foothills-Central Laramie County-
East Laramie County-
301 PM MDT Fri Sep 3 2021

This hazardous weather outlook is for portions of panhandle
Nebraska...east central Wyoming and southeast Wyoming.

.DAY ONE...THIS AFTERNOON AND TONIGHT

The area of concern will be south of a Wheatland to Chadron line.
Storm activity will spread northeast and east, reaching a peak
intensity by late afternoon. Main threats will be half dollar size
hail, wind gusts of 65 MPH, and repeated heavy rainfall. However
a short-lived tornado cannot be ruled out late this afternoon
and this evening over the northern half of the Nebraska Panhandle
as storms form a line there. Storm activity will end from west to
east this evening, with storms exiting the Nebraska Panhandle by
11 PM MDT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

No hazardous weather is expected at this time.

.Spotter information statement...

Spotter activation may be needed this afternoon and evening east
of I-25.

WYZ104-105-109>115-042115-
Ferris/Seminoe/Shirley Mountains-Shirley Basin-
Central Carbon County-North Snowy Range Foothills-
Southwest Carbon County-Sierra Madre Range-
Upper North Platte River Basin-Snowy Range-Laramie Valley-
301 PM MDT Fri Sep 3 2021

This hazardous weather outlook is for portions of south central
Wyoming and southeast Wyoming.

.DAY ONE...THIS AFTERNOON AND TONIGHT

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

The probability for widespread hazardous weather is low.

.Spotter information statement...

Spotter activation will not be needed.

JTL

In the hours before

Special weather statement, Sep 3, 1:38 PM MDT, 2 hours 7 minutes before

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Special weather statement, Sep 3, 2:20 PM MDT, 1 hour 25 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
220 PM MDT Fri Sep 3 2021

WYZ117-118-032045-
Central Laramie County WY-South Laramie Range Foothills WY-
220 PM MDT Fri Sep 3 2021

...A strong thunderstorm will impact portions of north central
Laramie County through 245 PM MDT...

At 220 PM MDT, Doppler radar was tracking a strong thunderstorm near
Whitaker, or 25 miles north of Cheyenne, moving east at 10 mph.

HAZARD...Winds in excess of 40 mph and nickel size hail.

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 north central
Laramie County.

This includes Interstate 25 in Wyoming between mile markers 32 and
38.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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 4146 10498 4152 10497 4158 10472 4148 10467
      4139 10472
TIME...MOT...LOC 2020Z 273DEG 9KT 4149 10494

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

Charnick

Special weather statement, Sep 3, 2:47 PM MDT, 58 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
247 PM MDT Fri Sep 3 2021

WYZ108-118-119-032130-
Goshen County WY-Central Laramie County WY-East Laramie County WY-
247 PM MDT Fri Sep 3 2021

...Strong thunderstorms will impact portions of southwestern Goshen
and northeastern Laramie Counties through 330 PM MDT...

At 246 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 14 miles southeast of Chugwater to 16 miles
west of Gun Barrel to 8 miles east of Whitaker. Movement was east at
25 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Gun Barrel and Meriden Rest Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4160 10427 4146 10431 4133 10438 4143 10480
      4152 10475 4161 10472
TIME...MOT...LOC 2046Z 280DEG 21KT 4160 10463 4151 10466 4143 10471

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

Charnick

Special weather statement, Sep 3, 3:30 PM MDT, 15 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
330 PM MDT Fri Sep 3 2021

NEZ020-054-WYZ108-118-119-032215-
Kimball NE-Banner NE-Goshen County WY-Central Laramie County WY-
East Laramie County WY-
330 PM MDT Fri Sep 3 2021

...Strong thunderstorms will impact portions of northwestern Kimball,
southwestern Banner, southeastern Goshen and northeastern Laramie
Counties through 415 PM MDT...

At 330 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles southeast of La Grange to 6 miles west
of Albin to near Gun Barrel. Movement was southeast at 35 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

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...
Albin, Gun Barrel and Bushnell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4148 10355 4128 10372 4122 10393 4145 10445
      4153 10430 4164 10423
TIME...MOT...LOC 2130Z 293DEG 31KT 4156 10411 4144 10422 4138 10438

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Charnick

Special weather statement, Sep 3, 3:45 PM MDT, 0 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
345 PM MDT Fri Sep 3 2021

WYZ117-118-032215-
Central Laramie County WY-South Laramie Range Foothills WY-
345 PM MDT Fri Sep 3 2021

...Strong outflow winds will impact portions of south central
Laramie County through 415 PM MDT...

At 344 PM MDT, Doppler radar was tracking strong outflow wind near
Warren Af Base, or near Cheyenne, moving east at 30 mph.

HAZARD...Outflow wind gusts in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Cheyenne, South Greeley, Hillsdale, Ranchettes, Warren AFB, Frontier
Park, North Cheyenne, Warren Af Base, Fox Farm-College and South
Greeley High.

This includes the following highways...
 Interstate 25 in Wyoming between mile markers 5 and 22.
 Interstate 80 in Wyoming between mile markers 353 and 379.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4112 10502 4120 10494 4131 10492 4127 10448
      4109 10447 4100 10457 4100 10474
TIME...MOT...LOC 2144Z 290DEG 25KT 4120 10489

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Charnick

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 3, 4:14 AM MDT	Special Weather Statement	CYS	Niobrara	46 min
Sep 3, 1:38 PM MDT	Special Weather Statement	CYS	Laramie	37 min
Sep 3, 2:20 PM MDT	Special Weather Statement	CYS	Laramie	25 min
Sep 3, 2:47 PM MDT	Special Weather Statement	CYS	Laramie	43 min
Sep 3, 3:53 PM MDT	Special Weather Statement	CYS	Laramie	37 min
Sep 3, 4:33 PM MDT	Special Weather Statement	CYS	Laramie	27 min
Sep 3, 4:45 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	31 min
Sep 3, 5:14 PM MDT	Areal Flood Advisory	CYS	Laramie	12 min
Sep 3, 5:25 PM MDT	Flash Flood Warning	CYS	Laramie	3 hr
Sep 3, 5:31 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Niobrara, Platte	26 min
Sep 3, 3:30 PM MDT	Special Weather Statement	CYS	Banner	45 min

Nearby

Special Weather Statements in Wyoming, 2021 Every special weather statement in 2021

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.