Alert archive / Wyoming / Special Weather Statements in 2011

Special Weather Statement, NWS Riverton, WY

July 11, 2011Sublette County, Wyoming

NWS Riverton, WY issued this special weather statement at Jul 11, 2011, 3:13 PM MDT for Sublette County, Wyoming. It was in force for 47 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 11, 2011, 3:13 PM MDT (21:13 UTC)
Expired
Jul 11, 2011, 4:00 PM MDT
In force
47 min
Issued by
NWS Riverton, WY

County Sublette County, WY

The radar

The Riverton/Lander radar (KRIW), 134 km from the middle of the area, began a volume at 21:15 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

Grand Junction, CO (KGJT), launched 12:00Z, 9.2 hours before the alert went out and 396 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, Grand Junction, CO at 12:00Z on 2011-07-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 171 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, Grand Junction, CO at 12:00Z on 2011-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.193958Sfc1 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
171 J/kg
Mixed-layer CIN
-134 J/kg
Mixed-layer LCL
1172 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
101 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

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 Riverton, WY wrote its last area forecast discussion before this special weather statement went out at Jul 11, 2:26 PM MDT, 47 minutes earlier.

Area forecast discussion, Jul 11, 2:26 PM MDT, 47 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
226 PM MDT MON JUL 11 2011

.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT

SOUTHWEST FLOW ALOFT WILL CONTINUE OVER WESTERN AND CENTRAL WYOMING
WITH MONSOON MOISTURE COMING NORTH FROM THE GREAT BASIN INTO THE
SOUTH...AND A PACIFIC TROUGH OFF THE BRITISH COLUMBIA COAST
BRINGING PACIFIC MOISTURE INTO NORTHWEST WYOMING AND PRODUCING
WEAK JET DYNAMICS...UPPER LEVEL DIVERGENCE. BEST LOW LEVEL
MOISTURE IN THE NORTHEAST...BUT RESPECTABLE MOISTURE AVAILABLE
OVER THE SOUTHWEST AS WELL. TYPICAL AFTERNOON CONVECTION FIRING
OFF THE MOUNTAINS WILL SPREAD ACROSS THE AREA THIS EVENING.
CONVECTION ACROSS UTAH AND WESTERN COLORADO WILL THEN MIGRATE
NORTH INTO SOUTHERN WYOMING THROUGH THE NIGHT SUPPORTING SHOWERS
AND THUNDERSTORMS INTO THE MORNING HOURS. MORE MOISTURE FROM THE
SOUTH WILL BE IN PLACE ON TUESDAY WITH AN INCREASE IN SHOWER AND
THUNDERSTORM COVERAGE. STILL WILL BE SOMEWHAT HIT AND MISS WITH NO
GREAT FOCUS FOR IDENTIFYING AREAS WITH THE GREATEST THREAT FOR
HEAVY RAIN. NOCTURNAL SHOWERS AND THUNDERSTORMS WILL AGAIN BE A
THREAT THROUGH TUESDAY NIGHT. WEDNESDAY WILL START TO DRY OUT WITH
A DECREASE IN COVERAGE. TEMPERATURES DURING THE DAY MAY BE
SLIGHTLY COOLER WITH MORE CLOUD COVER AND PRECIPITATION. STRONG
WIND GUSTS AND SMALL HAIL WILL BE THE MAIN THREAT WITH
THUNDERSTORMS. LESS CONVECTION SHOULD BE SEEN WEDNESDAY NIGHT AS
THE PACIFIC TROUGH MOVES EAST BRINGING A DRY SLOT OVER THE AREA
WITH MUCH LOWER PRECIPITABLE WATER AVAILABLE. LOW LEVEL MOISTURE
SHOULD DROP CONSIDERABLY WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

GLOBAL MODELS ARE PROGGING A DRY SOUTHWEST FLOW ACROSS THE AREA
THURSDAY THROUGH SATURDAY. VERY LITTLE OR NO DIURNAL CONVECTION
IS EXPECTED. COULD SEE RED FLAG WEATHER CONDITIONS...BREEZY SW
WIND AND VERY LOW RH...OVER PORTIONS OF THE AREA...BUT FUELS ARE
NOT CONSIDERED CRITICAL AT THIS TIME.

MODELS ARE SHOWING THE STRONG RIDGE OVER CENTRAL/SE CONUS SHIFTING
WESTWARD THIS WEEKEND INTO EARLY NEXT WEEK...WITH SLIGHTLY HIGHER
THICKNESS LEVELS. 700MB TEMPERATURES ARE EXPECTED TO RANGE BETWEEN
15 AND 20C BY EARLY NEXT WEEK. COULD SEE WIDESPREAD 90S
AGAIN...WITH SOME AREAS POSSIBLY REACHING THE CENTURY MARK.
ALTHOUGH THE RIDGE IS EXPECTED TO STRENGTHEN OVER THE AREA EARLY
NEXT WEEK...MODELS ARE PROGGING A SLIGHTLY BETTER MOISTURE PROFILE
THAN WHAT IS EXPECTED THURSDAY THROUGH SATURDAY. THUS...THE
FORECAST AREA SHOULD SEE A BETTER SHOT AT ISOLATED
AFTERNOON/EVENING CONVECTION SUNDAY AND MONDAY.

TEMPERATURES WILL BE SEASONAL TO SLIGHTLY ABOVE AVERAGE THURSDAY
THROUGH SATURDAY...WITH ABOVE AVERAGE TEMPERATURES BY 5-10 DEGREES
POSSIBLE BY SUNDAY AND MONDAY.

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL TODAY AND TONIGHT.  THUNDERSTORMS WILL
ONCE AGAIN INITIATE ON THE NORTHERN FRINGE THE MONSOONAL PLUME OF
MOISTURE OVER THE NORTHERN GREAT BASIN AND PUSH EAST NORTHEAST
ACROSS WEST AND CENTRAL WYOMING. SCATTERED COVERAGE OF STORMS AND
ISOLATED STRONGER STORMS WITH HEAVY RAIN AND HAIL ARE EXPECTED VCNTY
WEST AND NORTH OF A KEVW-KPNA-KCOD-KBYG LINE THIS EVENING. A DRIER
AIRMASS IN CENTRAL PORTIONS OF WYOMING...SOUTH OF THE AFOREMENTIONED
LINE...WILL RESULT IN ELEVATED CONVECTION WITH ERRATIC OUTFLOW WIND
GUSTS OF 35-45KT THE PRIMARY HAZARD. MOST STORMS WILL BE NORTH AND
EAST OF WYOMING BY 08Z TUESDAY.  BRIEF MVFR/IFR CONDITIONS IN HEAVY
DOWNPOURS AND/OR BLOWING DUST WILL BE POSSIBLE WITH STRONGER STORMS.
GREATER STORM COVERAGE IS EXPECTED ON TUES AS A SHORT WAVE MOVES
THROUGH THE AREA. THE STRONGEST STORMS ARE EXPECTED VCNTY KBYG AND
KCPR NORTH AND EAST WITH GUSTY WINDS AND HAIL AS THE PRIMARY
THREATS.

&&

.FIRE WEATHER...

A MONSOONAL PLUME OF MOISTURE WILL PUSH FURTHER NORTH ACROSS THE
AREA TONIGHT. STORMS WILL ONCE AGAIN INITIATE OVER THE NORTHERN
GREAT BASIN AND PUSH EAST NORTHEAST ACROSS THE DISTRICT THIS
EVENING WITH WIDELY SCATTERED COVERAGE EXPECTED OVER MOST OF THE
DISTRICT LATE THIS AFTERNOON THROUGH EVENING. STRONGER STORMS WITH
BETTER CHANCES OF WETTING RAIN OCCUR NEAR THE MONTANA BORDER WHILE
A DRIER AIRMASS WILL RESULT IN MAINLY HIGH-BASED STORMS WITH GUSTY
OUTFLOW WINDS FURTHER SOUTH. A SUB-TROPICAL DISTURBANCE WILL BRING
A BETTER CHANCE OF WETTING RAINS WITH STORMS ACROSS THE ENTIRE
DISTRICT ON TUESDAY. A DRIER AIRMASS WILL GRADUALLY PUSH INTO THE
DISTRICT WEDNESDAY AND THURSDAY. NO DISCERNIBLE TEMPERATURE TREND
IS EXPECTED OVER THE NEXT FEW DAYS.

&&

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

SHORT TERM...C.BAKER
LONG TERM...WM
AVIATION...ALLEN
FIRE WEATHER...C.BAKER
HYDROLOGY...C.BAKER
Hazardous weather outlook, Jul 11, 5:00 AM MDT, 10 hours 13 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
500 AM MDT MON JUL 11 2011

WYZ001>020-022>030-121200-
ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST-
BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES-
SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY-
TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN-
UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN-
WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
YELLOWSTONE NATIONAL PARK-
500 AM MDT MON JUL 11 2011

...FLOOD WARNING FOR THE WIND RIVER AROUND RIVERTON AND FOR SMALLER
CREEKS AND RIVERS OF SUBLETTE COUNTY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED THUNDERSTORMS WILL SPREAD OVER MUCH OF THE
AREA TODAY...ESPECIALLY THIS AFTERNOON AND EVENING. THE PRIMARY
HAZARDS ASSOCIATED WITH THIS STORM ACTIVITY WILL BE FREQUENT
LIGHTNING...STRONG WIND AND SMALL HAIL.

SNOWMELT DUE TO WARM TEMPERATURES WILL LEAVE SOME RIVERS AND STREAMS
RUNNING HIGH AND SWIFT TODAY...ESPECIALLY OVER FREMONT AND SUBLETTE
COUNTIES. ADDITIONALLY...THE YELLOWSTONE RIVER IN YELLOWSTONE
NATIONAL PARK WILL REMAIN HIGH WITH NEAR RECORD FLOWS POSSIBLE
THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

ALL CREEKS AND RIVERS ACROSS WEST CENTRAL WYOMING WILL CONTINUE TO
FALL BELOW FLOOD STAGES. WHILE RIVERS CONTINUE TO SLOWLY FALL...THEY
WILL STILL RUN HIGH AND SWIFT.

ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TUESDAY AND
WEDNESDAY AFTERNOON AND EVENINGS.  SOME OF THE STORMS HAVE THE
POTENTIAL TO BE STRONG...ESPECIALLY ON TUESDAY...WITH STRONG
WINDS AND HAIL.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT SEVERE WEATHER AND FLOODING TO THE
NATIONAL WEATHER SERVICE AT 1-800-211-1448. THANK YOU.

TEAM RIVERTON

In the hours before

Special weather statement, Jul 11, 2:31 PM MDT, 42 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
231 PM MDT MON JUL 11 2011

WYZ024>026-112115-
SALT RIVER AND WYOMING RANGES WY-UPPER GREEN RIVER BASIN WY-UPPER
GREEN RIVER BASIN FOOTHILLS WY-
231 PM MDT MON JUL 11 2011

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL SUBLETTE COUNTY UNTIL 315
PM MDT...

AT 224 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 8 MILES WEST OF BIG PINEY...MOVING EAST AT 20
MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

THIS STORM WILL BE NEAR...
STATE HWY 350 AROUND 240 PM MDT.
BIG PINEY AROUND 255 PM MDT.
SUBLETTE COUNTY FAIRGROUNDS AND MARBLETON AROUND 300 PM MDT.
HWY JCT 189 AND 351 AND U.S. HWY 189 MILE MARKER 110 AROUND 305 PM
MDT.

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

BRIEF 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.

REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
RIVERTON AT 1-800-211-1448.

LAT...LON 4286 10998 4235 10971 4233 11038 4263 11047
TIME...MOT...LOC 2031Z 271DEG 12KT 4258 11024

ALLEN
Special weather statement, Jul 11, 3:13 PM MDT, 0 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
313 PM MDT MON JUL 11 2011

WYZ025-026-112200-
UPPER GREEN RIVER BASIN WY-UPPER GREEN RIVER BASIN FOOTHILLS WY-
313 PM MDT MON JUL 11 2011

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN SUBLETTE COUNTY UNTIL
400 PM MDT...

AT 304 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR U.S. HWY 189 MILE MARKER 100...OR NEAR BIG
PINEY...MOVING EAST AT 20 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

THIS STORM WILL BE NEAR...
STATE HWY 351 MILE MARKER 10 AROUND 335 PM MDT.
JONAH FIELD AROUND 400 PM MDT.

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

BRIEF 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.

REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
RIVERTON AT 1-800-211-1448.

LAT...LON 4270 10978 4235 10962 4234 11020 4250 11029
TIME...MOT...LOC 2114Z 260DEG 16KT 4249 11003

ALLEN

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 2:31 PM MDTSpecial Weather StatementRIWSublette44 min
Jul 11, 3:37 PM MDTSpecial Weather StatementRIWSublette38 min
Jul 11, 4:13 PM MDTSpecial Weather StatementRIW47 min

Nearby

Special Weather Statements in Wyoming, 2011Every special weather statement in 2011

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.