Alert archive / Nebraska / Special Weather Statements in 2012

Special Weather Statement, NWS Cheyenne, WY

July 21, 2012Sioux County, Nebraska

NWS Cheyenne, WY issued this special weather statement at Jul 21, 2012, 5:29 PM MDT for Sioux County, Nebraska. It was in force for 61 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 21, 2012, 5:29 PM MDT (23:29 UTC)
Expired
Jul 21, 2012, 6:30 PM MDT
In force
61 min
Issued by
NWS Cheyenne, WY

County Sioux County, NE

The radar

The Rapid City radar (KUDX), 177 km from the middle of the area, began a volume at 23:28 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, 11.5 hours before the alert went out and 323 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, Denver, CO at 12:00Z on 2012-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 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, Denver, CO at 12:00Z on 2012-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 square meters per square second.1939Sfc1 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
3 J/kg
Mixed-layer CIN
-475 J/kg
Mixed-layer LCL
2634 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
36 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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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 Jul 21, 4:43 PM MDT, 46 minutes earlier.

Area forecast discussion, Jul 21, 4:43 PM MDT, 46 minutes before
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Hazardous weather outlook, Jul 21, 4:52 PM MDT, 37 minutes before
HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE CHEYENNE WY
452 PM MDT SAT JUL 21 2012

WYZ101>119-221245-
CONVERSE COUNTY LOWER ELEVATIONS-NIOBRARA COUNTY-
NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS-
SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY-
EAST PLATTE COUNTY-GOSHEN COUNTY-CENTRAL CARBON COUNTY-
NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY-
SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE-
LARAMIE VALLEY-SOUTH LARAMIE RANGE-SOUTH LARAMIE RANGE FOOTHILLS-
CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY-
452 PM MDT SAT JUL 21 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST WYOMING.

.DAY ONE...TONIGHT

SCATTERED EVENING THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA WITH
GUSTY WINDS AND BRIEF HEAVY RAIN. A FEW STRONGER THUNDERSTORMS MAY
CONTAIN SMALL HAIL. THE FREQUENT LIGHTNING FROM THESE STORMS MAY
ALSO AID IN PRODUCING FIRES...DUE TO VERY DRY CONDITIONS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE
EACH DAY AS MONSOON MOISTURE CONTINUES ACROSS THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND
CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT...
HTTP://WEATHER.GOV/CHEYENNE

NEZ002-003-019>021-054-055-095-096-221245-
DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE-
NORTH SIOUX-SOUTH SIOUX-
452 PM MDT SAT JUL 21 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA
PANHANDLE.

.DAY ONE...TONIGHT

ISOLATED EVENING THUNDERSTORMS ARE POSSIBLE MAINLY IN THE NORTHERN
PANHANDLE. GUSTY WINDS AND BRIEF HEAVY RAIN WILL BE POSSIBLE. A FEW
STRONGER THUNDERSTORMS MAY CONTAIN SMALL HAIL.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE EACH
DAY AS MONSOON MOISTURE CONTINUES ACROSS THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND
CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT...
HTTP://WEATHER.GOV/CHEYENNE

COX

In the hours before

Special weather statement, Jul 21, 4:47 PM MDT, 42 minutes before
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Special weather statement, Jul 21, 5:03 PM MDT, 26 minutes before
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Special weather statement, Jul 21, 5:05 PM MDT, 24 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
505 PM MDT SAT JUL 21 2012

WYZ107-108-116>119-220000-
CENTRAL LARAMIE COUNTY WY-EAST LARAMIE COUNTY WY-EAST PLATTE COUNTY
WY-GOSHEN COUNTY WY-SOUTH LARAMIE RANGE WY-SOUTH LARAMIE RANGE
FOOTHILLS WY-
505 PM MDT SAT JUL 21 2012

...THUNDERSTORM OUTFLOW BOUNDARY MOVING EASTWARD ACROSS LARAMIE
COUNTY...

AT 503 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A THUNDERSTORM OUTFLOW BOUNDARY ALONG A LINE EXTENDING
FROM 5 MILES SOUTHEAST OF CHUGWATER TO 6 MILES NORTH OF WHITAKER TO
7 MILES SOUTHWEST OF WHITAKER TO 6 MILES EAST OF FEDERAL TO CRYSTAL
LAKE CAMPGROUND TO 7 MILES NORTHEAST OF VIRGINIA DALE TO VIRGINIA
DALE...AND MOVING EAST AT 25 MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED AS THIS OUTFLOW BOUNDARY PASSES
ACROSS YOUR LOCATION. ISOLATED THUNDERSTORMS WILL DEVELOP ALONG THE
OUTFLOW BOUNDARY AND MAY AFFECT THE FRONTIER DAYS PARK AND
FESTIVITIES IN CHEYENNE AROUND 530 PM MDT PRODUCING WIND GUSTS TO 50
MPH AND LIGHT RAIN.

THE OUTFLOW BOUNDARY WILL BE NEAR...
WHITAKER AROUND 505 PM MDT.
NORTH CHEYENNE AROUND 525 PM MDT.
WARREN AF BASE AROUND 530 PM MDT.
FRONTIER PARK AROUND 535 PM MDT.
CHEYENNE AROUND 540 PM MDT.
SOUTH GREELEY HIGHWAY AND FOX FARM-COLLEGE AROUND 545 PM MDT.

THIS INCLUDES INTERSTATE 80 IN WYOMING BETWEEN MILE MARKERS 341 AND
368.

THIS INCLUDES INTERSTATE 25 IN WYOMING BETWEEN MILE MARKERS 0 AND 9.

&&

LAT...LON 4100 10530 4114 10517 4124 10503 4133 10501
      4150 10494 4175 10480 4178 10428 4136 10452
      4123 10456 4113 10471 4099 10486 4099 10530
TIME...MOT...LOC 2259Z 270DEG 20KT 4171 10472 4150 10487
          4134 10495 4124 10497 4115 10510 4101 10522
          4089 10538

RUBIN
Special weather statement, Jul 21, 5:11 PM MDT, 18 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
511 PM MDT SAT JUL 21 2012

WYZ117-118-220015-
CENTRAL LARAMIE COUNTY WY-SOUTH LARAMIE RANGE FOOTHILLS WY-
511 PM MDT SAT JUL 21 2012

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN LARAMIE COUNTY UNTIL 615
PM MDT...

AT 510 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR WHITAKER...OR 16 MILES NORTH OF CHEYENNE...
MOVING NORTHEAST AT 15 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 55 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING.

THIS STORM WILL BE NEAR...
WHITAKER AROUND 515 PM MDT.

THIS INCLUDES INTERSTATE 25 IN WYOMING BETWEEN MILE MARKERS 13 AND
43.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

&&

LAT...LON 4162 10490 4142 10439 4115 10486 4120 10517
TIME...MOT...LOC 2312Z 223DEG 12KT 4137 10487

RUBIN
Special weather statement, Jul 21, 5:14 PM MDT, 15 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
514 PM MDT SAT JUL 21 2012

WYZ106>108-220015-
CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY WY-EAST PLATTE
COUNTY WY-GOSHEN COUNTY WY-
514 PM MDT SAT JUL 21 2012

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN PLATTE AND WESTERN GOSHEN
COUNTIES UNTIL 615 PM MDT...

AT 505 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 5 MILES SOUTHEAST OF WHEATLAND...MOVING NORTHEAST
AT 20 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

THIS STORM WILL BE NEAR...
GRAYROCKS RESERVOIR AROUND 540 PM MDT.
FORT LARAMIE NATIONAL HISTORIC SITE AROUND 615 PM MDT.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

HEAVY RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 4239 10465 4197 10438 4194 10490 4204 10495
TIME...MOT...LOC 2314Z 240DEG 16KT 4203 10482

RUBIN
Special weather statement, Jul 21, 5:29 PM MDT, 0 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
529 PM MDT SAT JUL 21 2012

NEZ095-096-WYZ102-108-220030-
GOSHEN COUNTY WY-NIOBRARA COUNTY WY-NORTH SIOUX NE-SOUTH SIOUX NE-
529 PM MDT SAT JUL 21 2012

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL SIOUX...SOUTHEASTERN
NIOBRARA AND EXTREME NORTHEASTERN GOSHEN COUNTIES UNTIL 630 PM MDT...

AT 524 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 10 MILES WEST OF HARRISON...OR 21 MILES EAST OF
LUSK...MOVING EAST AT 15 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING.

THIS STORM WILL TRACK EAST ALONG HIGHWAY 20 BETWEEN VAN TASSELL AND
HARRISON THROUGH 615 PM MDT.

THIS STORM WILL BE NEAR...
HARRISON AROUND 605 PM MDT.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

&&

LAT...LON 4294 10372 4241 10371 4261 10416 4277 10417
TIME...MOT...LOC 2328Z 266DEG 12KT 4266 10405

RUBIN

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 3:09 PM MDTSpecial Weather StatementCYSNiobrara66 min
Jul 21, 3:17 PM MDTSpecial Weather StatementCYSAlbany58 min
Jul 21, 3:31 PM MDTSpecial Weather StatementCYSAlbany59 min
Jul 21, 3:45 PM MDTSpecial Weather StatementCYSPlatte60 min
Jul 21, 3:51 PM MDTSpecial Weather StatementCYSAlbany54 min
Jul 21, 4:26 PM MDTSpecial Weather StatementCYSPlatte64 min
Jul 21, 4:30 PM MDTSevere Thunderstorm WarningCYSPlatte60 min
Jul 21, 4:47 PM MDTSpecial Weather StatementCYSPlatte58 min
Jul 21, 5:03 PM MDTSpecial Weather StatementCYSLaramie57 min
Jul 21, 5:05 PM MDTSpecial Weather StatementCYSLaramie55 min
Jul 21, 5:11 PM MDTSpecial Weather StatementCYSLaramie64 min
Jul 21, 5:14 PM MDTSpecial Weather StatementCYSPlatte61 min
Jul 21, 5:54 PM MDTSpecial Weather StatementCYSGoshen66 min

Nearby

Special Weather Statements in Nebraska, 2012Every special weather statement in 2012

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.