Severe Thunderstorm Warning 86, NWS Cheyenne, WY

897 
WWUS55 KCYS 090235
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
835 PM MDT FRI JUN 8 2018

NEC013-090300-
/O.CON.KCYS.SV.W.0086.000000T0000Z-180609T0300Z/
Box Butte NE-
835 PM MDT FRI JUN 8 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM MDT
FOR NORTHEASTERN BOX BUTTE COUNTY...

At 835 PM MDT, severe thunderstorms were located along a line
extending from 19 miles south of Hay Springs to near Wild Horse
Butte, moving east at 15 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Wild Horse Butte.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Cheyenne.

&&

LAT...LON 4224 10293 4237 10295 4244 10282 4244 10275
      4223 10274
TIME...MOT...LOC 0235Z 269DEG 14KT 4240 10270 4229 10287 

HAIL...<.75IN
WIND...60MPH
 
$$

Hammer

925 
WWUS55 KCYS 090246
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
846 PM MDT FRI JUN 8 2018

NEC013-090256-
/O.CAN.KCYS.SV.W.0086.000000T0000Z-180609T0300Z/
Box Butte NE-
846 PM MDT FRI JUN 8 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN BOX BUTTE COUNTY
IS CANCELLED...
    
The storms which prompted the warning have moved out of the area.
Therefore the warning has been cancelled.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Cheyenne.

LAT...LON 4224 10293 4237 10295 4244 10282 4244 10275
      4223 10274
TIME...MOT...LOC 0243Z 274DEG 13KT 4240 10266 4229 10283 

$$

Hammer

Area Forecast Discussion
National Weather Service Cheyenne WY
552 PM MDT Fri Jun 8 2018

.UPDATE...
Issued at 304 PM MDT Fri Jun 8 2018

THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH
163 IN EFFECT UNTIL 10 PM MDT THIS EVENING FOR THE FOLLOWING
AREAS

IN NEBRASKA THIS WATCH INCLUDES 3 COUNTIES

IN WESTERN NEBRASKA

BOX BUTTE             DAWES                 SIOUX

IN WYOMING THIS WATCH INCLUDES 2 COUNTIES

IN EAST CENTRAL WYOMING

NIOBRARA

IN SOUTHEAST WYOMING

GOSHEN

THIS INCLUDES THE CITIES OF AGATE, ALLIANCE, CHADRON,
CHADRON ST PARK, HARRISON, LUSK, REDBIRD, AND TORRINGTON.

.Mesoscale Update...
Storms are developing along the Laramie Range and in a maturing
CU field across the Nebraska Panhandle. LAPS and observations
showed mid to low 60s dewpoints across Nebraska and mid 50s
across southeast Wyoming. This moisture under steep mid level
lapse rates was generating 5500 j/kg of SBCAPE. Shear is on the
weaker side with 0-6km Bulk shear at or about 30 kts. This should
favor a mixed multicell/weak supercell mode with the threat for
large hail, damaging winds, and an isolated tornado. The tornado
threat in particular appears fairly marginal with about 100 m2/s2
0-3km helicity. Storms will mature rapidly in the large CAPE
environment and will likely congeal into a more solid line later
this evening. This line/ MCS would have the potential for a
damaging wind threat as it translates east southeast.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 235 PM MDT Fri Jun 8 2018

A few forecast concerns in the short term forecast today. First
off, severe thunderstorm potential today, then winds and fire
weather concerns this weekend.

Currently...Surface low pressure system being analyzed on analysis
near the northeast corner of Niobrara County this afternoon. A
Dryline being analyzed near the Wyoming/Nebraska border extending
south along the Front Range. IR Satellite imagery showing
supercells developing across northeast Wyoming into western South
Dakota. SPC Mesoanalysis page showing surface based CAPE around
5500 J/KG over most of the Panhandle with around 3000 J/KG up to
the I-25 Corridor in southeast Wyoming. Very humid in the
Panhandle with 2PM dewpoints in the mid 60s at Chadron, 60 at
Sidney and 68 at Alliance. Storms are beginning to form on radar
along the Laramie Range, especially up near Douglas.

Latest HRRR showing convection becoming severe here shortly across
northern Goshen County and then moving northeast into the richer
CAPE/instability. Likely intensifying as they track across the
northern Panhandle. Bowing structure/squall line signature being
seen on simulated radar across the northern Panhandle after 00Z,
so strong winds and hail look to be the primary hazards. Looks
like convection ends/moves east by 03/04Z this evening.

For Saturday, southwest winds are going to be on the increase
across Carbon County. GFS 700mb winds increase to 30-35kts.
Forecast soundings show mixing up to 525mbs, so its going to be
windy across Carbon County. Afternoon humidity down into the
single digits with these winds. Fuels were just turned over to Yes
for 305, 307 and 309, so a Red Flag Warning was warranted for 305
and 307.

Even stronger winds Sunday as a dry cold front moves across the
area. GFS 700mb winds up to 50kts and soundings showing winds
mixing at 500mbs of 50 to 55kts. So we could be flirting with high
wind criteria along with critical fire weather conditions. Issued
a Fire Weather Watch for 305, 307 and 309.

.LONG TERM...(Monday through Friday)
Issued at 235 PM MDT Fri Jun 8 2018

Dry, breezy and cooler Monday as the upper trough axis swings
well east of the area and surface high pressure builds into the
region. Dry conditions should then continue through Weds as the
CWA resides under westerly upper flow with temperatures warming.
A passing weak impulse may set off a bit of convection Thursday
as moisture begins to increase. Friday should see the approach of
the next upper shortwave from the northwest with a little better
chance for convection late in the day.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 547 PM MDT Fri Jun 8 2018

Wyoming TAFS...VFR at Rawlins with wind gusts to 25 knots through
03Z and to 32 knots after 15Z Saturday. VFR at Laramie with
isolated thunderstorms in the vicinity through 02Z and wind gusts
to 23 knots through 02Z and to 23 knots after 15Z. VFR at Cheyenne
with isolated thunderstorms through 02Z producing wind gusts to 40
knots. Wind gusts to 20 knots after 15Z Saturday.

Nebraska TAFS...VFR at Chadron, Alliance and Scottsbluff with
isolated thunderstorms through 03Z producing wind gusts to 45
knots along with brief MVFR. Wind gusts to 26 knots after 15Z
Saturday. VFR at Sidney with thunderstorms in the vicinity through
03Z and wind gusts to 20 knots through 03Z and to 24 knots after
15Z Saturday.

&&

.FIRE WEATHER...
Issued at 235 PM MDT Fri Jun 8 2018

Fuels have been reported ready in FWZs 305, 307 and 309 just
today. Expect a windy period for Saturday through Monday,
initially beginning across Carbon County Saturday. These winds
will become more widespread Sunday across much of southeast
Wyoming and Nebraska Panhandle as a dry cold front approaches. The
front looks to move through the area Sunday evening with winds
shifting from west to northwest. In the meantime, strong winds and
very low humidity is expected to create critical fire weather
issues for FWZ 305 and 307 Saturday and 305, 307 and 309 Sunday.
Red Flag Warnings are in effect for 305 and 307 Saturday, with
watches in effect 305, 307 and 309 Sunday. Most other areas in
southeast Wyoming and Nebraska Panhandle will see the strong
winds and low humidity, especially Sunday. But fuels are still
reported not receptive.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from 11 AM to 8 PM MDT Saturday for WYZ305-307.

     Fire Weather Watch from Sunday morning through Sunday evening
     for WYZ305-307-309.

NE...None.
&&

UPDATE...ADL
SHORT TERM...GCC
LONG TERM...RE
AVIATION...RUBIN
FIRE WEATHER...GCC

Hazardous Weather Outlook
National Weather Service Cheyenne WY
214 PM MDT Fri Jun 8 2018

NEZ002-003-019>021-054-055-095-096-WYZ101-102-107-108-118-119-
092015-
Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne-
North Sioux-South Sioux-Converse County Lower Elevations-
Niobrara County-East Platte County-Goshen County-
Central Laramie County-East Laramie County-
214 PM MDT Fri Jun 8 2018

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

.SEVERE THUNDERSTORM WATCH #163 IN EFFECT UNTIL 10 PM MDT FOR BOX
BUTTE DAWES SIOUX GOSHEN AND NIOBRARA COUNTIES...

Strong to severe storms are expected to develop with the threat of
large hail to the size of quarters, damaging winds in excess of 60
mph, and an isolated tornado. Spotter activation will likely be
needed late this afternoon and evening.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

Isolated thunderstorms are expected on Saturday afternoon, however
the chances for severe storms will be less. A couple of stronger
storms over far eastern Wyoming and the western Nebraska Panhandle
will be possible, with winds to around 50 mph and hail to the size
of quarters. Thunderstorm chances Sunday through Wednesday will be
fairly low, however chances for afternoon and evening
thunderstorms will increase again by Thursday.

WYZ103>106-109>117-092015-
North Laramie Range-Ferris/Seminoe/Shirley Mountains-
Shirley Basin-Central Laramie Range and Southwest Platte 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-
214 PM MDT Fri Jun 8 2018

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

.SEVERE THUNDERSTORM WATCH #163 IN EFFECT UNTIL 10 PM MDT FOR BOX
BUTTE DAWES SIOUX GOSHEN AND NIOBRARA COUNTIES...

Isolated thunderstorms are possible this evening.
Severe weather is primarily expected further to the northeast but
an isolated severe storm is possible through 8 pm.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

Thunderstorm chances Saturday through Wednesday will be fairly
low, with most of any showers and thunderstorms expected to form
near the mountains. Chances for afternoon and evening thunderstorms
will increase again region-wide by Thursday.

.Spotter information statement...

Activation of storm spotters is not expected through Saturday.

Special Weather Statement
National Weather Service Cheyenne WY
408 PM MDT FRI JUN 8 2018

WYZ101-082300-
Converse County Lower Elevations WY-
408 PM MDT FRI JUN 8 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN CONVERSE COUNTY
UNTIL 500 PM MDT...

At 407 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles northwest of Bill, or 30 miles south of Wright, moving east at
30 mph.

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

Locations impacted include...
Bill and Dull Center.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4322 10553 4331 10564 4341 10556 4348 10496
      4317 10495
TIME...MOT...LOC 2207Z 263DEG 28KT 4331 10539

Lyons

Special Weather Statement
National Weather Service Cheyenne WY
432 PM MDT FRI JUN 8 2018

WYZ101-102-082315-
Converse County Lower Elevations WY-Niobrara County WY-
432 PM MDT FRI JUN 8 2018

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL NIOBRARA AND EAST
CENTRAL CONVERSE COUNTIES UNTIL 515 PM MDT...

At 432 PM MDT, Doppler radar was tracking a strong thunderstorm 11
miles southwest of Manning Ranch, or 17 miles northeast of Douglas,
moving east at 20 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Manning Ranch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

A severe thunderstorm watch remains in effect until 1000 PM MDT for
east central Wyoming.

LAT...LON 4280 10517 4287 10530 4297 10525 4311 10487
      4286 10476
TIME...MOT...LOC 2232Z 250DEG 19KT 4292 10512

Lyons

Special Weather Statement
National Weather Service Cheyenne WY
519 PM MDT FRI JUN 8 2018

WYZ101-102-090000-
Converse County Lower Elevations WY-Niobrara County WY-
519 PM MDT FRI JUN 8 2018

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL NIOBRARA AND EAST
CENTRAL CONVERSE COUNTIES UNTIL 600 PM MDT...

At 518 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 15 miles northwest of Lance Creek to near
Manning Ranch to 17 miles northwest of Keeline. Movement was east at
15 mph.

Half inch hail and wind gusts of 50 to 55 mph will be possible with
these storms.

Locations impacted include...
Manning Ranch and Lance Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

A severe thunderstorm watch remains in effect until 1000 PM MDT for
east central Wyoming.

LAT...LON 4328 10456 4279 10477 4283 10512 4302 10532
      4326 10500
TIME...MOT...LOC 2318Z 248DEG 14KT 4317 10487 4304 10492 4292 10501

Lyons

Special Weather Statement
National Weather Service Cheyenne WY
619 PM MDT FRI JUN 8 2018

NEZ096-WYZ108-090100-
South Sioux NE-Goshen County WY-
619 PM MDT FRI JUN 8 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN SIOUX AND EAST
CENTRAL GOSHEN COUNTIES UNTIL 700 PM MDT...

At 619 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles northeast of Torrington, moving east at 30 mph.

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

Locations impacted include...
Torrington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

A severe thunderstorm watch remains in effect until 1000 PM MDT for
the Panhandle of Nebraska...and southeastern Wyoming.

LAT...LON 4206 10419 4214 10429 4223 10425 4238 10369
      4207 10369
TIME...MOT...LOC 0019Z 256DEG 27KT 4217 10413

Lyons

Special Weather Statement
National Weather Service Cheyenne WY
738 PM MDT FRI JUN 8 2018

NEZ002-003-090230-
Box Butte NE-Dawes NE-
738 PM MDT FRI JUN 8 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN BOX BUTTE AND
SOUTHEASTERN DAWES COUNTIES UNTIL 830 PM MDT...

At 738 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Wild Horse Butte, or 17 miles north of Alliance,
moving northeast at 30 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Hemingford, Wild Horse Butte and Berea.

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.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Cheyenne.

&&

A severe thunderstorm watch remains in effect until 1000 PM MDT for
the Panhandle of Nebraska.

LAT...LON 4215 10299 4237 10313 4257 10277 4245 10277
      4244 10275 4216 10274
TIME...MOT...LOC 0138Z 243DEG 28KT 4236 10289

Hammer