Severe Thunderstorm Warning 261, NWS Cheyenne, WY

568 
WWUS55 KCYS 142204
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
404 PM MDT TUE AUG 14 2018

WYC021-142230-
/O.CON.KCYS.SV.W.0261.000000T0000Z-180814T2230Z/
Laramie WY-
404 PM MDT TUE AUG 14 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM MDT
FOR SOUTH CENTRAL LARAMIE COUNTY...

At 404 PM MDT, a severe thunderstorm was located 8 miles west of
Carpenter, or 16 miles southeast of Cheyenne, moving southeast at 25
mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Carpenter.

This includes Interstate 80 in Wyoming between mile markers 373 and
381.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4110 10471 4118 10459 4116 10445 4110 10426
      4100 10430 4100 10477
TIME...MOT...LOC 2204Z 293DEG 21KT 4104 10451 

HAIL...0.75IN
WIND...60MPH
 
$$

Allen

052 
WWUS55 KCYS 142212
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
412 PM MDT TUE AUG 14 2018

WYC021-142222-
/O.CAN.KCYS.SV.W.0261.000000T0000Z-180814T2230Z/
Laramie WY-
412 PM MDT TUE AUG 14 2018

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL LARAMIE COUNTY
IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

LAT...LON 4110 10471 4118 10459 4116 10445 4110 10426
      4100 10430 4100 10477
TIME...MOT...LOC 2210Z 283DEG 21KT 4103 10445 

$$

Allen

Area Forecast Discussion
National Weather Service Cheyenne WY
214 PM MDT Tue Aug 14 2018

.SHORT TERM...(This evening through Wednesday)
Issued at 159 PM MDT Tue Aug 14 2018

A stalled cold front is the focus of activity today as monsoon
moisture has combined with heightened atmospheric instability to
generate thunderstorms along and east of the Laramie Range already
today as of 2 PM MDT. Storms have already become quite strong
with small hail being the main threat so far. Strong to severe
thunderstorms are expected across southeast Wyoming and into the
western Nebraska Panhandle this afternoon and evening with SB CAPE
values near 1500 to 2500 J/kg and strong mid-layer shear values.
Main threats will be large hail and damaging winds, with locally
heavy rains as PWATs are near 1 inch. Will continue to monitor
these storms closely as they develop and move east.

Overnight, areas of fog will be possible, especially in areas that
receive rain today. Not expecting fog to be quite as widespread as
it was last night.

As we move into Wednesday, the stalled front will be the focus of
activity yet again, as similar factors combine to produce strong
to severe thunderstorms. This time however, thunderstorm
development will be limited to the eastern-most portions of WY and
east into the Nebraska Panhandle. Dry air will build into the
western portions of the CWA as a ridge of high pressure builds
east into the region.

.LONG TERM...(Thursday through Monday)
Issued at 315 AM MDT Tue Aug 14 2018

Rocky Mountain upper ridge becomes the dominant feature Thursday
and Friday with northwest flow aloft. Diurnal convection will be
limited to the southeast WY mountains and foothills both days. Near
average temperatures will prevail. The next upper trough to bring
more widespread shower/thunderstorm activity will track east from
the Pacific Northwest across MT/WY Saturday and northern/central
Plains Sunday. The attendant surface low and cold front will pass
through the CWA by late Saturday evening. Preliminary QPF from a
quarter to half inch is forecast, with locally heavier amounts
possible in thunderstorms. There is a small chance for strong to
severe convection. The precipitation ends from west to east Sunday
night. There is a slight chance for afternoon/evening convection
Monday with the passage of a trailing shortwave across southeast
WY. Temperatures will cool to below seasonal normals Sunday and
Monday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1148 AM MDT Tue Aug 14 2018

VFR conditions primarily prevail across the direct TAF sites but
an area of TSRA is shifting across Niobrara County that extends
southwest into Platte and Albany Counties towards KLAR. Areas of
MVFR to IFR are likely in the heavier showers and thunderstorm
activity as this TSRA band moves from west to east. KCDR will
likely be near or directly impacted by this line over the next
several hours. Will time in TSRA directly as it approaches the
area and confidence increases. Additional SHRA/TSRA is expected to
develop along the southern edge of this band over the Laramie
Mountain Range through the afternoon. This activity will shift
east as well and be near KLAR/KCYS and could also enter Nebraska
near KBFF. Lower confidence exists if storms will be able to make
it to KAIA or KSNY this afternoon. All activity should diminish by
04-05Z.

Winds will generally be east to southeast for the High Plains
sites of WY and NE and 15-20 kt. Winds will decrease to below 10
knots after 04Z.

Isolated to scattered areas of MVFR to IFR low ceilings could be
possible once again Wednesday morning per NAM sounding profiles
near KCYS. Have tilted forecast towards lower ceilings and will
monitor for lower or more overcast possibilities.

&&

.FIRE WEATHER...
Issued at 159 PM MDT Tue Aug 14 2018

A stalled surface front is the focal point today and tomorrow of
shower and thunderstorm development as monsoon moisture streams
north and combines with general atmospheric instability. A few of
these storms will be strong to severe; threats will be damaging
winds and large hail. Today will also carry the threat of locally
heavy rainfall amounts. Areas near Carbon County will be dry
through the period with RH values near 15% for the period, though
winds will remain below critical thresholds. Changing weather
conditions will occur by the wend of the week as a ridge of high
pressure builds back into the region.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

SHORT TERM...AB
LONG TERM...MAJ
AVIATION...JSA
FIRE WEATHER...AB

Hazardous Weather Outlook
National Weather Service Cheyenne WY
229 PM MDT Tue Aug 14 2018

NEZ002-003-019>021-054-055-095-096-WYZ101>103-105>108-115>119-
152030-
Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne-
North Sioux-South Sioux-Converse County Lower Elevations-
Niobrara County-North Laramie Range-Shirley Basin-
Central Laramie Range and Southwest Platte County-
East Platte County-Goshen County-Laramie Valley-
South Laramie Range-South Laramie Range Foothills-
Central Laramie County-East Laramie County-
229 PM MDT Tue Aug 14 2018

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

Isolated to scattered thunderstorms this afternoon and evening. A
few strong to severe storms with large hail and wind gusts in
excess of 60 mph are possible over much of east central and
southeast Wyoming into the extreme western Nebraska Panhandle.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Isolated to scattered afternoon and evening thunderstorms will
develop Friday through Sunday. Severe weather is not expected at
this time.

.Spotter information statement...

Spotter activation will not be required.

WYZ104-109>114-152030-
Ferris/Seminoe/Shirley Mountains-Central Carbon County-
North Snowy Range Foothills-Southwest Carbon County-
Sierra Madre Range-Upper North Platte River Basin-Snowy Range-
229 PM MDT Tue Aug 14 2018

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

Isolated afternoon and early evening thunderstorms will develop.
Gusty winds and occasional lightning will be the primary hazards.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Isolated afternoon and evening thunderstorms Friday will become
scattered this weekend. Severe weather is not expected at this
time.

.Spotter information statement...

Spotter activation will not be required.

Special Weather Statement
National Weather Service Cheyenne WY
1240 PM MDT TUE AUG 14 2018

WYZ103-105-106-115-141930-
Shirley Basin WY-
Central Laramie Range and Southwest Platte County WY-
North Laramie Range WY-Laramie Valley WY-
1240 PM MDT TUE AUG 14 2018

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL ALBANY COUNTY UNTIL 130
PM MDT...

At 1240 PM MDT, Doppler radar was tracking a strong thunderstorm near
Wheatland Reservoir 3, or 40 miles north of Laramie, moving east at
20 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Wheatland Reservoir 3.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4183 10592 4195 10591 4198 10554 4176 10563
TIME...MOT...LOC 1840Z 275DEG 15KT 4187 10580

Allen

Special Weather Statement
National Weather Service Cheyenne WY
116 PM MDT TUE AUG 14 2018

WYZ106-115>117-142000-
South Laramie Range WY-
Central Laramie Range and Southwest Platte County WY-
South Laramie Range Foothills WY-Laramie Valley WY-
116 PM MDT TUE AUG 14 2018

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL ALBANY COUNTY UNTIL
200 PM MDT...

At 116 PM MDT, Doppler radar was tracking a strong thunderstorm near
Baldy Peak, or 16 miles north of Laramie, moving east at 15 mph.

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

Locations impacted include...
Baldy Peak.

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 4147 10568 4165 10566 4165 10528 4140 10528
TIME...MOT...LOC 1916Z 275DEG 15KT 4156 10557

Allen

Special Weather Statement
National Weather Service Cheyenne WY
129 PM MDT TUE AUG 14 2018

WYZ106-107-117-118-142015-
East Platte County WY-
Central Laramie Range and Southwest Platte County WY-
Central Laramie County WY-South Laramie Range Foothills WY-
129 PM MDT TUE AUG 14 2018

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN ALBANY...NORTHWESTERN
LARAMIE AND SOUTHWESTERN PLATTE COUNTIES UNTIL 215 PM MDT...

At 129 PM MDT, Doppler radar was tracking a strong thunderstorm near
Iron Mountain, or 29 miles northeast of Laramie, moving east at 10
mph.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Iron Mountain.

LAT...LON 4154 10528 4173 10528 4173 10491 4147 10497
TIME...MOT...LOC 1929Z 280DEG 9KT 4164 10521

Allen

Special Weather Statement
National Weather Service Cheyenne WY
150 PM MDT TUE AUG 14 2018

WYZ106-115>117-142045-
South Laramie Range WY-
Central Laramie Range and Southwest Platte County WY-
South Laramie Range Foothills WY-Laramie Valley WY-
150 PM MDT TUE AUG 14 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN ALBANY AND
NORTHWESTERN LARAMIE COUNTIES UNTIL 245 PM MDT...

At 149 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Iron Mountain to 6 miles west of Horse
Creek to 6 miles north of Yellow Pine Campground. Movement was
southeast at 20 mph.

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

Locations impacted include...
Tie City Campground, Horse Creek, North Crow Campground, Iron
Mountain and Yellow Pine Campground.

This includes Interstate 80 in Wyoming between mile markers 320 and
324.

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.

&&

LAT...LON 4157 10504 4137 10506 4114 10529 4123 10545
      4131 10553 4142 10542 4164 10540
TIME...MOT...LOC 1949Z 284DEG 19KT 4156 10531 4144 10530 4135 10541

Allen

Special Weather Statement
National Weather Service Cheyenne WY
257 PM MDT TUE AUG 14 2018

WYZ104-105-142130-
Shirley Basin WY-Ferris/Seminoe/Shirley Mountains WY-
257 PM MDT TUE AUG 14 2018

...SPECIAL WEATHER STATEMENT...

At 257 PM MDT, Doppler radar was tracking a strong thunderstorm 10
miles southeast of Independence Rock, or 44 miles north of Rawlins,
moving east at 35 mph.

Half inch hail will be possible with this storm.

This storm will remain over mainly rural areas of north central
Carbon County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential 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 4243 10706 4243 10645 4218 10653 4232 10709
TIME...MOT...LOC 2057Z 282DEG 32KT 4240 10697

Braun

Special Weather Statement
National Weather Service Cheyenne WY
322 PM MDT TUE AUG 14 2018

WYZ117>119-142200-
Central Laramie County WY-South Laramie Range Foothills WY-
East Laramie County WY-
322 PM MDT TUE AUG 14 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL LARAMIE COUNTY
UNTIL 400 PM MDT...

At 322 PM MDT, Doppler radar was tracking a strong thunderstorm over
South Greeley, or near Cheyenne, moving southeast at 20 mph.

Nickel size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

Locations impacted include...
Cheyenne, Carpenter and Ranchettes.

This includes Interstate 80 in Wyoming between mile markers 367 and
383.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4115 10470 4127 10471 4124 10452 4107 10428
      4100 10432 4100 10482
TIME...MOT...LOC 2122Z 294DEG 19KT 4109 10475

Allen