Alert archive / Wyoming / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 63, NWS Riverton, WY

July 27, 2015Fremont County, Hot Springs County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 27, 2015, 4:12 PM MDT for Fremont County, Hot Springs County, Wyoming. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 27, 2015, 4:12 PM MDT (22:12 UTC)
Expired
Jul 27, 2015, 5:00 PM MDT
In force
48 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Fremont County, WY, Hot Springs County, WY

The radar

The Riverton/Lander radar (KRIW), 35 km from the middle of the area, began a volume at 22:13 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 4, 1:08 PM MDTSevere Thunderstorm WatchSPC112 days

The nearest sounding before it

Rapid City, SD (KRAP), launched 12:00Z, 10.2 hours before the alert went out and 461 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, Rapid City, SD at 12:00Z on 2015-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 237 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, Rapid City, SD at 12:00Z on 2015-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.19395878Sfc1 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
237 J/kg
Mixed-layer CIN
-666 J/kg
Mixed-layer LCL
1635 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Riverton, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 27, 2:36 PM MDT, 1 hour 36 minutes earlier.

Area forecast discussion, Jul 27, 2:36 PM MDT, 1 hour 36 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
236 PM MDT MON JUL 27 2015

.SHORT TERM...TONIGHT THROUGH TUESDAY

A WEAK STATIONARY FRONTAL BOUNDARY APPEARS TO BE DRAPED EAST TO
WEST ALONG THE OWL CREEK MTNS AND ALONG THE JOHNSON/NATRONA COUNTY
LINE. NORTH OF THE BOUNDARY DEW POINTS ARE IN THE 40S AND 50S AND
SOUTH OF THE BOUNDARY THEY ARE ONLY IN THE 20S. MEANWHILE A STRONG
PACIFIC COLD FRONT IS PLOWING ITS WAY EAST ACROSS FAR WESTERN WY
AND WILL EVENTUALLY  THE AIRMASS ACROSS ALL OF WESTERN AND
CENTRAL WY THIS EVENING AS THE NORTHERN THIRD OF WYOMING
EXPERIENCES A SFC FRONTAL OCCLUSION. AS THIS PACIFIC FRONT
PROGRESSES EAST...THE POTENTIAL FOR STRONG THUNDERSTORMS EXISTS
ACROSS NORTHERN WY IN THE AREA OF HIGHER DEW POINTS AND RESULTANT
HIGHER CAPES. SPC HAS THIS AREA UNDER MARGINAL SO LARGE HAIL AND
DAMAGING WINDS ARE A POSSIBILITY IN THESE AREAS THROUGH AT LEAST
EARLY THIS EVENING. SO FAR...SMALL HAIL HAS BEEN REPORTED AT
MAMMOTH AND DUBOIS AND AS FAR SOUTH AS CASPER.

THE OTHER AREA OF CONCERN IS THE ON GOING RED FLAG WARNING FOR
PORTIONS OF THE CENTRAL...EASTERN AND SOUTHERN PORTIONS OF THE CWA
WHERE MINIMUM RH VALUES RANGING FROM THE UPPER SINGLE DIGITS TO
THE LOW TEENS HAVE BEEN COMMON ALONG WITH WINDS GUSTING AS HIGH
AS 35 KNOTS FROM THE SOUTHWEST AHEAD OF THE APPROACHING PACIFIC
COLD FRONT WITH EVEN STRONGER SHIFTING WINDS ANTICIPATED WITH THE
FROPA. WITH 3 HOURLY SFC PRESSURE RISES ANTICIPATED TO BE UP TO
12MB...MANY AREAS COULD SEE POST FRONTAL WIND GUSTS OF UP TO 50
MPH. IN ADDITION...A HAINES INDEX OF SIX IS IN PLACE IN THESE
AREAS...NOT TO MENTION THE SMALL POSSIBILITY OF A DRY LIGHTNING
STRIKE. WILL LET THE RED FLAG RIDE THROUGH 10 PM THIS EVENING FOR
FIRE WEATHER ZONES 279...280...281...283...285 AND 300.

THE AFOREMENTIONED PACIFIC COLD FRONT IS BEING SLUNG BY A VIGOROUS
EASTBOUND SHORTAVE FOR THIS TIME OF YEAR WHICH HAS BEEN TRACKING
EAST ACROSS MONTANA. THIS TROUGH WILL CLOSE OFF OVER EAST CENTRAL
MONTANA BY 06Z TONIGHT AND BECOME ALMOST VERTICALLY STACKED. THERE
IS PLENTY OF COLD AIR FOR THIS TIME OF YEAR WRAPPING AROUND THE
BACKSIDE OF THIS LOW WITH H7 TEMPS EXPECTED TO DROP BETWEEN -2 AND
-3C IN NW WYOMING LATER TONIGHT. IN FACT...TEMPS ARE ALREADY ONLY
IN THE 50S IN THE FAR WEST BEHIND THE FRONT. WITH THESE COLD H7
TEMPS...SNOW LEVELS SHOULD DROP TO BETWEEN 7K AND 7500 FEET IN
YELLOWSTONE PARK LATER TONIGHT THROUGH TUESDAY MORNING WHERE UP
TO A HALF INCH OF SNOW COULD FALL JUST BEFORE THE WX SYSTEM PULLS
OUT TO THE EAST AND THE RESULTANT AREA OF PRECIP SHRINKS. AREAS
LIKE TOGWOTEE PASS COULD SEE A PERIOD OF SNOWFALL AROUND MIDNIGHT
TONIGHT WITH GRANITE AND POWDER RIVER PASSES TO FOLLOW. THE
SOUTHERN WINDS COULD SEE A VERY BRIEF PERIOD OF LIGHT WET SNOW
ABOVE 8500 FEET IN THE WEE HOURS TUESDAY MORNING BEFORE SUNRISE.

FOR TUESDAY...A COOLER BUT PLEASANTLY MILD AND SUNNY DAY IS IN
STORE. WEST NORTHWEST WINDS WILL DIMINISH AS THE MONTANA WEATHER
SYSTEM CONTINUES TO PULL AWAY.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY

HIGH PRESSURE OVER THE AREA WILL KEEP WARM AND DRY CONDITIONS
THROUGH MUCH OF THE FORECAST PERIOD. MODELS IN GOOD AGREEMENT WITH
THIS QUIET SOLUTION FOR WESTERN AND CENTRAL WYOMING.

CONDITIONS BEGIN TO CHANGE SUNDAY MORNING AS A WEAK DISTURBANCE
BEGINS TO MOVE TOWARDS THE STATE. THIS SYSTEM WILL GENERATE SOME
SHOWER AND THUNDERSTORM ACTIVITY SUNDAY AFTERNOON AND
EVENING...ESPECIALLY OVER NORTHERN AND WESTERN WYOMING. MODELS ARE
NOT IN GOOD AGREEMENT WITH THE PROGRESSION OF THIS SHOWER
ACTIVITY... BUT WILL LEAVE FORECAST TRENDING TOWARDS THE SOLUTION
FOR LOW COVERAGE OF SHOWERS AND THUNDERSTORMS. THE ECMWF INDICATES A
BETTER PUSH OF MOISTURE AND INSTABILITY ON MONDAY WITH EXPECTED
ZONAL FLOW. ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
ACROSS MUCH OF THE FORECAST AREA UNDER THIS SOLUTION. THE GFS IS NOT
AS AGGRESSIVE...WITH WEAKER MOISTURE AND INSTABILITY. UNDER ITS
SCENARIO...SHOWER COVERAGE WOULD CONTINUE TO BE FAIRLY LIMITED TO
THE NORTHERN AND WESTERN MOUNTAINS.

REGARDLESS...EXPECT GENERALLY WARMING CONDITIONS THROUGH MUCH OF THE
FORECAST PERIOD...WITH SLIGHTLY COOLER TEMPERATURES POSSIBLE SUNDAY
AND MONDAY.

&&

.AVIATION.../00Z ISSUANCE/

A STRONG PACIFIC COLD FRONT WILL CONTINUE TO PUSH INTO WEST AND
CENTRAL WYOMING THROUGH AREAS EAST OF THE DIVIDE LATER THIS
AFTERNOON AND EVENING. ISOLATED TO SCATTERED -TSRA WILL DEVELOP
ALONG THE FRONT MAINLY VCNTY AND NORTH OF A KJAC- KWRL-KBYG LINE
IN THE LATE AFTERNOON AND EVENING. SFC SW WINDS AT 20-35KTS WILL
PRECEDE THE FRONT WITH THE STRONGER WINDS FROM VCNTY KRKS-KCPR AND
ALONG THE EAST SLOPES FROM VCNTY KTHP-KLND. LLWS IN ADDITION TO
CONVECTIVE WIND SHEAR MAY BE ENCOUNTERED BEHIND THE COLD FRONT
VCNTY KCOD- KBYG THROUGH THE REMAINDER OF THE AFTERNOON WITH A
PREVAILING NORTHERLY SFC WIND AND SW WINDS 20-30KTS AT RIDGETOP
LEVEL UNTIL THE STRONG PACIFIC COLD FRONT ARRIVES FROM THE WEST.
SFC WEST WINDS AT 20-30KTS WILL FOLLOW THE COLD FRONT ACROSS
CENTRAL AND SOUTHERN WYOMING. WINDS WILL GRADUALLY DIMINISH
OVERNIGHT. THE NORTHERN ABSAROKA AND BIGHORN RANGES WILL LIKELY
REMAIN FQTLY OBSCURED WITH SCT -SHRA/-SHSN MONDAY NIGHT INTO
TUESDAY MORNING.

&&

.FIRE WEATHER...

...RED FLAG WARNING FOR ZONES 280 281 283 285 AND 300 THROUGH 10PM
TONIGHT...

JUST ABOUT EVERY ELEMENT WORTHY OF A RED FLAG WARNING WILL BE
PRESENT THROUGH THIS EVENING FROM WIDESPREAD STRONG WIND OVER 35
MPH ACROSS THE AREA WITH GUSTS AROUND 50 MPH POSSIBLE IN THE MORE
EXPOSED AND WIND PRONE AREAS...TO LOW HUMIDITY...TO DRY
THUNDERSTORMS AND A DRY COLD FRONT. AREAS EXPECTED TO BE MOST
AFFECTED WILL BE CASPER DISPATCH...SOUTHERN CODY DISPATCH...AND
RAWLINS DISPATCH AS THEY WILL HAVE THE MOST TIME AHEAD OF THE COLD
FRONT IN THE HOT AND DRY SOUTHWEST FLOW. MOST OF THE WET
THUNDERSTORM ACTIVITY WILL BE IN TETON DISPATCH WITH SEVERE
THUNDERSTORMS POSSIBLE IN NORTHERN CASPER AND CODY DISPATCH WITH
HAZARDS THAT RANGE FROM LARGE HAIL TO A TORNADO...WITH DAMAGING
DOWNBURST WINDS THE MOST LIKELY HAZARD THROUGH EARLY THIS EVENING.
IT WILL BE QUITE A BIT CALMER AND COOLER BEHIND THE FRONT FOR
TUESDAY BUT IT WILL REMAIN DRY...ESPECIALLY ACROSS THE SOUTHERN
THIRD OF THE STATE...WINDS WILL CALMER BUT A FEW GUSTS TO 25 MPH
CANNOT BE RULED OUT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 10 PM MDT THIS EVENING FOR WYZ279>281-283-
285-300.

&&

SHORT TERM...LIPSON
LONG TERM...BRANHAM
AVIATION...LIPSON
FIRE WEATHER...LIPSON
Hazardous weather outlook, Jul 27, 3:20 AM MDT, 12 hours 52 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
320 AM MDT MON JUL 27 2015

WYZ001>020-022>030-281100-
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-
320 AM MDT MON JUL 27 2015

...HIGH FIRE DANGER TODAY FOR MUCH OF CENTRAL WYOMING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

SEVERE THUNDERSTORMS WITH ALL HAZARDS POSSIBLE FROM A TORNADO TO
FLASH FLOODING TO DAMAGING WINDS IN JOHNSON COUNTY AND THE
NORTHERN BIGHORN BASIN THIS AFTERNOON ALONG A COLD FRONT.
THUNDERSTORMS WILL ALSO BE POSSIBLE ACROSS WESTERN WYOMING THOUGH
STORMS WILL BE LESS SEVERE...THEY WILL STILL BE CAPABLE OF
PRODUCING HAIL AND GUSTY WINDS ALONG WITH DANGEROUS LIGHTNING.

ELEVATED FIRE WEATHER CONDITIONS EAST OF THE DIVIDE AND
ACROSS THE SOUTH...WHERE WINDS WILL BE STEADY AT 25 TO 35 MPH
WITH FREQUENT GUSTS OVER 40 MPH...OUTDOOR BURNING IS STRONGLY
DISCOURAGED ACROSS WESTERN AND CENTRAL WYOMING TODAY.

TONIGHT...MUCH COLDER BEHIND THE FRONT WITH SNOW POSSIBLE ABOVE
9000FT IN NORTHWEST WYOMING INCLUDING YELLOWSTONE NATIONAL PARK
AND GRAND TETON NATIONAL PARK.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

TUESDAY...COOLER...WITH FREEZING TEMPERATURES POSSIBLE IN THE
WESTERN MOUNTAINS AND VALLEYS. ELEVATED FIRE WEATHER CONDITIONS
CONTINUE OVER SOUTHERN WYOMING.

SUNDAY...ISOLATED THUNDERSTORMS ACROSS THE NORTH.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT HEAVY RAIN...ALL SEVERE
THUNDERSTORM HAZARDS IN ADDITION TO WIND GUSTS GREATER THAN 45 MPH
AND ANY WIND DAMAGE. THANK YOU.

In the hours before

Special weather statement, Jul 27, 2:55 PM MDT, 1 hour 17 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
255 PM MDT MON JUL 27 2015

WYZ017-019-272130-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-WIND RIVER BASIN-
255 PM MDT MON JUL 27 2015

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL FREMONT COUNTY UNTIL
330 PM MDT...

AT 254 PM MDT...DOPPLER RADAR WAS TRACKING A LINE OF THUNDERSTORM
OUTFLOW ALONG A LINE EXTENDING FROM NEAR SHOSHONI TO 9 MILES NORTH
OF SAND DRAW...AND MOVING NORTHEAST AT 45 MPH.

WIND GUSTS OF 50 TO 55 MPH WILL BE POSSIBLE WITH THESE STORMS.

STRONG THUNDERSTORMS WILL BE NEAR...
  SHOSHONI AROUND 300 PM MDT.
  BOYSEN STATE PARK HEADQUARTERS AROUND 305 PM MDT.
  LYSITE AND MONETA AROUND 330 PM MDT.

OTHER LOCATIONS IMPACTED BY THESE STORMS INCLUDE SHOSHONI MUNICIPAL
AIRPORT...BOYSEN STATE PARK AND BONNEVILLE.

#

LAT...LON 4274 10760 4269 10792 4276 10821 4340 10829
      4342 10815 4340 10810 4342 10809 4338 10804
      4339 10804 4339 10794 4337 10791 4340 10790
      4339 10778 4343 10776 4345 10779 4346 10772
      4343 10768 4343 10763 4337 10753
TIME...MOT...LOC 2054Z 220DEG 38KT 4328 10818 4290 10815

ANGLIN
Special weather statement, Jul 27, 3:25 PM MDT, 47 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
325 PM MDT MON JUL 27 2015

WYZ001-002-012-013-023>025-280000-
YELLOWSTONE NATIONAL PARK-ABSAROKA MOUNTAINS-
TETON AND GROS VENTRE MOUNTAINS-JACKSON HOLE-STAR VALLEY-
SALT RIVER AND WYOMING RANGES-UPPER GREEN RIVER BASIN FOOTHILLS-
INCLUDING THE CITIES OF...CANYON...LAKE...MADISON...MAMMOTH...
OLD FAITHFUL...TOWER JUNCTION...PAHASKA...JACKSON...AFTON...
ALPINE...FOSSIL BUTTE NATIONAL MON...PINEDALE
325 PM MDT MON JUL 27 2015

A COLD FRONT WILL CONTINUE TO MOVE THROUGH WESTERN WYOMING THROUGH
THE REMAINDER OF THIS AFTERNOON AND EVENING ALONG WITH SHOWERS
AND THUNDERSTORMS. THE PRIMARY LINE OF SHOWERS AND THUNDERSTORMS
ASSOCIATED WITH THE FRONT CURRENTLY EXTEND FROM PINEDALE...NORTH
TO NEAR UNION PASS. THIS LINE OF STORMS WILL CONTINUE TO MOVE
EAST. 45 TO 55 MPH WINDS CAN BE EXPECTED ALONG THIS LINE OF
STORMS IN MANY AREAS. SOME OF THESE STORMS COULD ALSO PRODUCE
HAIL SMALL HAIL AND BRIEF HEAVY DOWNPOURS. IT WILL BE VERY COLD
BEHIND THE FRONT WITH SNOW POSSIBLE ABOVE 9000FT THIS
EVENING....INCLUDING YELLOWSTONE. CLEARING IS EXPECTED AFTER
MIDNIGHT WITH FREEZING TEMPERATURES POSSIBLE ACROSS MUCH OF THE
AREA EARLY TUESDAY MORNING.

WYZ005-007-014>016-019-026>030-280000-
SOUTHWEST BIG HORN BASIN-OWL CREEK AND BRIDGER MOUNTAINS-
WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST-
UPPER WIND RIVER BASIN-GREEN MOUNTAINS AND RATTLESNAKE RANGE-
UPPER GREEN RIVER BASIN-SOUTH LINCOLN COUNTY-
ROCK SPRINGS AND GREEN RIVER-FLAMING GORGE-EAST SWEETWATER COUNTY-
INCLUDING THE CITIES OF...THERMOPOLIS...ATLANTIC CITY...DUBOIS...
JEFFREY CITY...BAIROIL...MARBLETON...LA BARGE...BIG PINEY...
EDEN...FARSON...KEMMERER...DIAMONDVILLE...ROCK SPRINGS...
GREEN RIVER...WAMSUTTER...SUPERIOR
325 PM MDT MON JUL 27 2015

HOT...DRY...WINDY AND UNSTABLE CONDITIONS AHEAD OF AN APPROACHING
STORM SYSTEM WILL CREATE AN UNFAVORABLE BURNING ENVIRONMENT THIS
AFTERNOON AS ANY FIRES THAT START COULD QUICKLY BECOME
UNCONTROLLABLE.

IN ADDITION...SCATTERED THUNDERSTORMS ARE RAPIDLY DEVELOPING
ACROSS THE AREA AS TEH COLD FRONT APPROACHES FROM THE WEST. DRY
LIGHTNING IS POSSIBLE ALONG WITH STRONG AND ERRATIC WIND GUSTS OF
45 TO 55 MPH FROM THESE THUNDERSTORMS DURING THE REMAINDER OF THE
AFTERNOON AND EARLY EVENING.

PLEASE BE EXTRA CAUTIOUS WITH FIRE THIS AFTERNOON. BE MINDFUL OF
WHAT COULD CAUSE A SPARK...NOT ALL SOURCES ARE OBVIOUS...FOR
INSTANCE...DO NOT PARK A TRUCK OR ATV IN TALL GRASS AND BE SURE
THAT YOU SECURE ANY CHAINS INVOLVED IN TOWING A VEHICLE. SOME OF
THE MORE OBVIOUS SOURCES INCLUDE ABANDONED CAMPFIRES...
WELDING...AND AGRICULTURAL BURNING.

FOR MORE INFORMATION AND RESOURCES ON OUTDOOR FIRE SAFETY...VISIT
WEATHER.GOV/RIVERTON/AGBURNING.

WYZ003-004-006-008>011-280000-
CODY FOOTHILLS-NORTH BIG HORN BASIN-SOUTHEAST BIG HORN BASIN-
BIGHORN MOUNTAINS WEST-BIGHORN MOUNTAINS SOUTHEAST-
NORTHEAST JOHNSON COUNTY-SOUTHEAST JOHNSON COUNTY-
INCLUDING THE CITIES OF...CODY...POWELL...LOVELL...GREYBULL...
WORLAND...BUFFALO...KAYCEE
325 PM MDT MON JUL 27 2015

STRONG THUNDERSTORMS WILL BE POSSIBLE FOR THE REMAINDER OF THIS
AFTERNOON AND EVENING AS A COLD FRONT SHIFTS SOUTHEAST. VARIOUS HAZARDS
WILL BE POSSIBLE INCLUDING LARGE HAIL AND DAMAGING DOWNBURST WINDS
BEING THE MOST LIKELY THREAT. CURRENTLY...A LINE OF SHOWERS AND
THUNDERSTORMS EXTENDS FROM UNION PASS ALONG THE CONTINENTAL DIVIDE
NORTH TO CLARK IN NORTHERN PARK COUNTY. THIS LINE OF STORMS HAS
HAD A HISTORY OF PRODUCING 45 TO 55 MPH WINDS AND WILL CONTINUE TO
MOVE EAST.

AHEAD OF THE FRONT IT WILL BE VERY DRY WITH GUSTY SOUTHWEST WINDS
IN EXCESS OF 45 MPH AT TIMES... RESULTING IN VERY HIGH FIRE
DANGER...ESPECIALLY IN JOHNSON COUNTY.

LIPSON
Special weather statement, Jul 27, 3:43 PM MDT, 29 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
343 PM MDT MON JUL 27 2015

WYZ004-272215-
NORTH BIG HORN BASIN-
343 PM MDT MON JUL 27 2015

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN BIG HORN COUNTY UNTIL 415
PM MDT...

AT 342 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 10
MILES NORTHWEST OF OTTO...WHICH IS 19 MILES WEST OF GREYBULL...MOVING
NORTHEAST AT 40 MPH.

HALF INCH HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS
STORM.

THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF WESTERN BIG HORN
COUNTY...INCLUDING THE FOLLOWING LOCATIONS...BURLINGTON...BASIN SOUTH
BIG HORN COUNTY HOSPITAL...MIDWAY GOLF COURSE...GREYBULL SOUTH BIG
HORN COUNTY AIRPORT...BIG HORN COUNTY FAIRGROUNDS...GREYBULL PUBLIC
SCHOOLS...GREYBULL BURLINGTON NORTHERN SANTA FE RAILROAD YARD...
EMBLEM...GREEN OASIS CAMPGROUND AND GREYBULL HIGH SCHOOL.

#

LAT...LON 4434 10847 4449 10862 4496 10829 4433 10768
TIME...MOT...LOC 2142Z 233DEG 34KT 4447 10846

BRANHAM
Local storm report, Jul 27, 4:09 PM MDT, 3 minutes before
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Local storm report, Jul 27, 4:10 PM MDT, 2 minutes before
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Local storm report, Jul 27, 4:11 PM MDT, 1 minute before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 26, 6:23 PM MDTSpecial Weather StatementRIW37 min
Jul 27, 2:00 PM MDTSpecial Weather StatementRIWWashakie45 min
Jul 27, 2:03 PM MDTSpecial Weather StatementRIWNatrona27 min
Jul 27, 2:18 PM MDTSpecial Weather StatementRIWPark42 min
Jul 27, 2:24 PM MDTSpecial Weather StatementRIW36 min
Jul 27, 2:55 PM MDTSpecial Weather StatementRIW35 min
Jul 27, 3:43 PM MDTSpecial Weather StatementRIWBig Horn32 min
Jul 27, 3:48 PM MDTSevere Thunderstorm WarningRIWBig Horn27 min
Jul 27, 4:12 PM MDTSevere Thunderstorm WarningRIWBig Horn33 min
Jul 27, 4:39 PM MDTSpecial Weather StatementRIW36 min
Jul 27, 4:51 PM MDTSevere Thunderstorm WarningRIWFremont23 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2015Every severe thunderstorm warning in 2015

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.