Severe Thunderstorm Warning 39, NWS Riverton, WY

322 
WWUS55 KRIW 092051
SVSRIW

Severe Weather Statement
National Weather Service Riverton WY
251 PM MDT SUN JUL 9 2017

WYC029-092101-
/O.EXP.KRIW.SV.W.0039.000000T0000Z-170709T2100Z/
Park-
251 PM MDT SUN JUL 9 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN PARK COUNTY WILL
EXPIRE AT 300 PM MDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore the warning will be allowed to expire.  However small hail
and gusty winds are still possible with this thunderstorm.

LAT...LON 4500 10985 4483 10985 4487 11024 4500 11024
TIME...MOT...LOC 2051Z 269DEG 13KT 4496 11008 

$$

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Area Forecast Discussion
National Weather Service Riverton WY
146 PM MDT Sun Jul 9 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 147 PM MDT Sun Jul 9 2017

A large high pressure center rotating about over the Great Basin
with zonal westerly flow over southern Canada and the northern Rockies
will bring limited moisture and a series of weak short wave low pressure
troughs across the area through Wednesday.  Showers and isolated
thunderstorms driven mainly by daytime heating will develop each afternoon
and evening mainly over the mountains.  Strong wind gusts will continue
to be the main threat with the Thunderstorms.  Overall little change in
temperatures is expected with slight cooling a best through Wednesday.
Relative humidity will be rather low with light wind away from
thunderstorms.

.LONG TERM...(Wednesday night through Sunday)
Issued at 147 PM MDT Sun Jul 9 2017

A large high pressure center rotating about over the Great Basin
with zonal westerly flow over southern Canada and the northern Rockies
will bring limited moisture and a series of weak short wave low pressure
troughs across the area Wednesday night through Sunday.  Showers and isolated
thunderstorms driven mainly by daytime heating will develop each afternoon
and evening mainly over the mountains.  Strong wind gusts will continue
to be the main threat with the Thunderstorms.  Overall little change in
temperatures is expected with warming expected Wednesday night through Sunday.
Relative humidity will be rather low with light wind away from
thunderstorms.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 147 PM MDT Sun Jul 9 2017

VFR conditions to prevail through the period. Showers and
thunderstorms continue to develop this afternoon, with coverage
being more widespread than Saturday. Outflow wind gusts of 30 to 40
knots will continue to be the main threat, along with locally heavy
rain possible with some storms. Local MVFR visibilities can be
expected in these areas of heavy rain. Storms will transition to
showers after 03Z and remain widespread across northern and central
portions through 08Z Monday. Isolated showers will be possible near
KRKS-KBPI-KPNA during this time. Mountains may be obscured at times,
especially from 06Z-18Z Monday west of the Divide, as additional
clouds and possible showers move in during this time.

&&

.FIRE WEATHER...
Issued AT 147 PM MDT Sun Jul 9 2017

A large high pressure center rotating about over the Great Basin
with zonal westerly flow over southern Canada and the northern Rockies
will bring limited moisture and a series of weak short wave low pressure
troughs across the area through Wednesday.  Showers and isolated
thunderstorms driven mainly by daytime heating will develop each afternoon
and evening mainly over the mountains.  Strong wind gusts will continue
to be the main threat with the Thunderstorms.  Overall little change in
temperatures is expected with slight cooling a best through Wednesday.
Relative humidity will be rather low with light wind away from
thunderstorms.   The lower air mass will be unstable from late morning to
mid evening with sufficient mixing and wind for very good to excellent smoke
dispersal each day.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...Baker
LONG TERM...Baker
AVIATION...LaVoie
FIRE WEATHER...Baker

Hazardous Weather Outlook
National Weather Service Riverton WY
137 AM MDT Sun Jul 9 2017

WYZ001>020-022>030-101200-
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-
137 AM MDT Sun Jul 9 2017

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...Today and Tonight

Isolated thunderstorms this afternoon and evening. Any storm can
have strong outflow winds. The strongest storms will be across the
northern zones.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Monday...Isolated to widely scattered afternoon and evening
thunderstorms. Gusty outflow wind will be common near any
activity. Strong to severe thunderstorms are possible across
northern Wyoming.

Wednesday through Saturday...Isolated afternoon and evening
thunderstorms mainly over the mountains and adjacent foothills.
The main hazard will be strong, gusty winds.

.SPOTTER INFORMATION STATEMENT...

Spotters are urged to report wind gusts over 45 mph and any
size hail. Thank you.

Team Riverton

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
139 PM MDT SUN JUL 09 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0122 PM     TSTM WND GST     CASPER                  42.83N 106.33W
07/09/2017  M60 MPH          NATRONA            WY   ASOS

&&

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Special Weather Statement
National Weather Service Riverton WY
206 PM MDT Sun Jul 9 2017

WYZ001-100100-
Yellowstone National Park-
Including the cities of Lake, Mammoth, and Old Faithful
206 PM MDT Sun Jul 9 2017

...Showers and Thunderstorms this afternoon/evening over portions
of Yellowstone...

Widely scattered showers and thunderstorms will continue over the
park this afternoon. Most of these storms will be over northern
portions of the park, moving to the east-northeast. Isolated to
scattered lightning strikes will be common, along with gusty winds
up to 50 mph and small hail.

Special Weather Statement
National Weather Service Riverton WY
216 PM MDT SUN JUL 9 2017

WYZ002-015-016-092045-
Upper Wind River Basin-Wind River Mountains East-Absaroka Mountains-
216 PM MDT SUN JUL 9 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN FREMONT COUNTY UNTIL
245 PM MDT...

At 215 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles northwest of Dubois, moving northeast at 15 mph.

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

This strong thunderstorm will be near...
  Dubois around 220 PM MDT.

Other locations impacted by this storm include Dubois Municipal
Airport, Double Cabin Campground, Antelope Hills Golf Course and
Crooked Creek Guest Ranch.

LAT...LON 4351 10978 4367 10990 4385 10959 4362 10940
TIME...MOT...LOC 2015Z 239DEG 14KT 4363 10976

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