Alert archive / Wyoming / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 166, NWS Cheyenne, WY
NWS Cheyenne, WY issued this severe thunderstorm warning at Aug 8, 2009, 7:20 PM MDT for Laramie County, Wyoming. It was in force for 29 min. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 8, 2009, 7:20 PM MDT (01:20 UTC)
- Expired
- Aug 8, 2009, 7:49 PM MDT
- In force
- 29 min
- Issued by
- NWS Cheyenne, WY
- Area
- Storm-based polygon
County Laramie County, WY
The radar
The Cheyenne radar (KCYS), 42 km from the middle of the area, began a volume at 01:21 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 8, 7:22 PM MDT | HAIL 1 | 7 Wnw Burns, WY | ONE INCH DIAMETER HAIL REPORTED IN HILLSDALE. |
| Aug 8, 7:30 PM MDT | HAIL 1.75 | 8 N Burns, WY |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
Did it verify
Verified. The Iowa Environmental Mesonet's Cow matched 2 storm reports to this severe thunderstorm warning; the first came 2 minutes after it went out.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The nearest sounding before it
Denver, CO (KDNR), launched 00:00Z, 1.3 hours before the alert went out and 189 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.
- Mixed-layer CAPE
- 94 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 3551 m above ground
- 0-6 km bulk shear
- 75 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 202 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS55 KCYS 090120 SVRCYS WYC021-090200- /O.NEW.KCYS.SV.W.0166.090809T0120Z-090809T0200Z/ BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE CHEYENNE WY 720 PM MDT SAT AUG 8 2009 THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... EAST CENTRAL LARAMIE COUNTY IN SOUTHEAST WYOMING... * UNTIL 800 PM MDT * AT 718 PM MDT...THE PUBLIC REPORTED A SEVERE THUNDERSTORM PRODUCING QUARTER SIZE HAIL NEAR HILLSDALE. THIS STORM WAS LOCATED 5 MILES WEST OF BURNS...OR 18 MILES EAST OF CHEYENNE...AND MOVING NORTHEAST AT 15 MPH. * LOCATIONS IMPACTED INCLUDE... GUN BARREL AND HWY 85 AT HIGHWAY 216. PRECAUTIONARY/PREPAREDNESS ACTIONS... IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE HAIL AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS. && LAT...LON 4147 10438 4134 10411 4117 10445 4123 10451 TIME...MOT...LOC 0120Z 229DEG 11KT 4122 10445 $$ RE
2 follow-up statements
000 WWUS55 KCYS 090139 SVSCYS SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 739 PM MDT SAT AUG 8 2009 WYC021-090200- /O.CON.KCYS.SV.W.0166.000000T0000Z-090809T0200Z/ LARAMIE WY- 739 PM MDT SAT AUG 8 2009 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM MDT FOR EASTERN LARAMIE COUNTY... AT 736 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL. THIS STORM WAS LOCATED NEAR BURNS...OR 24 MILES EAST OF CHEYENNE...MOVING NORTHEAST AT 20 MPH. LOCATIONS IMPACTED INCLUDE... BURNS. PRECAUTIONARY/PREPAREDNESS ACTIONS... IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE HAIL AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS. && LAT...LON 4126 10441 4147 10438 4134 10411 4121 10438 TIME...MOT...LOC 0138Z 247DEG 16KT 4124 10434 $$ RE
000 WWUS55 KCYS 090149 SVSCYS SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 749 PM MDT SAT AUG 8 2009 WYC021-090159- /O.CAN.KCYS.SV.W.0166.000000T0000Z-090809T0200Z/ LARAMIE WY- 749 PM MDT SAT AUG 8 2009 ...THE SEVERE THUNDERSTORM WARNING FOR EASTERN LARAMIE COUNTY IS CANCELLED... THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED AND NO LONGER APPEARED TO BE SEVERE...HOWEVER HEAVY RAIN AND SMALL HAIL IS STILL POSSIBLE WITH THIS THUNDERSTORM. LAT...LON 4126 10441 4147 10438 4134 10411 4121 10438 TIME...MOT...LOC 0149Z 247DEG 16KT 4126 10428 $$ RE
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 Cheyenne, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 8, 2:45 PM MDT, 4 hours 35 minutes earlier.
Area forecast discussion, Aug 8, 2:45 PM MDT, 4 hours 35 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 245 PM MDT SAT AUG 8 2009 .SHORT TERM...TONIGHT THRU MON...GOOD LOW LEVEL CONVERGENCE DVLPG ALONG SRN LAR RANGE...WITH SEMI-MOIST UPSLOPE E/NE WINDS OVER FAR SE WY. EXPECTING SOME TSTMS TO FIRE OVER HIGHER TERRAIN AND DRIFT NEWD ACROSS PLAINS LATE THIS AFTN INTO THIS EVENING. A FEW STORMS WILL BE CAPABLE OF MAINLY SMALL HAIL AND BRIEF HEAVY RAIN. WATER VAPOR SATELLITE PIXS SHOWS A FTR OVER SE UT WHICH WILL BE MOVING NEWD THIS EVENG AIDING TSTM DVLPMNT. LINGERING MAIN PIECE OF UPPER TROF BACK OVER ERN NV TO ID WILL SHIFT E STARTING TONIGHT WITH GOOD UPPER JET ON EAST SIDE OF SYSTEM. MODELS SHOW A BREAKOUT OF SHWRS/TSTMS LATER TONIGHT INTO SUN MRNG WITH THE EJECTING TROF ACROSS MUCH OF THE AREA. HAVE UPPED POPS BUT PROBABLY NOT ENUF GIVEN STRENGTH OF THE SYSTEM. UPPER TROF MOVES OUT OF THE REGION SUN AFTN...BUT ENOUGH MSTR AND MARGINAL INSTBLTY FOR SOME AFTN SHWRS/TSTMS. MODELS HAVE BEEN SHOWING A WEAK LAGGING PART OF THE UPPER TROF CAUSING SOME SHWRS/TSTMS OVER MAINLY NERN CO SUN NIGHT FOR A FEW RUNS...SO HAVE ADDED SOME PCPN CHCS NEAR THE CO BORDER. YET ANOTHER UPPER FTR IS FCST TO MOVE INTO THE REGION ON MON AFTN...SO HAVE SPREAD SOME POPS BACK INTO THE REGION MAINLY SE THIRD OF THE AREA. TEMPS ON SUN COULD BE TRICKY ESPCLY IN THE PNHNDL WHERE CLOUDS WILL LINGER THE LONGEST. WARMER ON MON WITH MORE SUNSHINE. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY... KEPT A VERY LOW POP FOR TSTMS AT SE EDGE OF CWA MONDAY EVENING WITH MINOR DISTURBANCE EXITING AREA. AFTER THIS...UPPER RIDGING WILL DOMINATE THE WX TUESDAY THROUGH THURSDAY GETTING TEMPS BACK UP TO AND ABOVE NORMAL UNDER MOSTLY CLEAR SKIES. THERE COULD BE AN ISOLATED LATE DAY TSTM OR TWO OVER EASTERN CWA WEDNESDAY AND THURSDAY LIKE THE ECMWF SHOWS VS. DRY GFS...BUT KEPT IT OUT OF FORECAST FOR NOW. ON FRIDAY...RIDGE FLATTENS AND FLOW ALOFT BECOMES WSW. TEMPS WILL REMAIN ON WARM SIDE FRIDAY BUT THERE WILL BE A FEW TSTMS AT LEAST OVER THE MOUNTAINS AS MID LEVEL MOISTURE INCREASES. ON SATURDAY...ECMWF AND GFS SIMILAR IN SHOWING AN UPPER TROUGH SWEEPING ACROSS MT AND MAINLY NORTHERN WY WITH A COLD FRONT PUSHING INTO CWA. FOR NOW...HAVE LOWERED MAX TEMPS SOME AND ADDED A FEW TSTMS TO THE NORTHERN AND WESTERN PARTS OF THE CWA ALTHOUGH THESE MAY NEED TO BE INCLUDED OVER MOST AREAS. && .AVIATION...SCATTERED SHOWERS AND TSTMS OVER MUCH OF THE REGION OVERNIGHT INTO SUN MRNG WITH PTCHY MVFR CONDITIONS MAINLY EAST OF THE MTNS INTO THE PNHNDL 09Z-16Z. && .FIRE WEATHER...COOL UPPER SYSTEM OVER ID/UT WILL SHIFT EAST OVERNIGHT INTO SUN ACROSS THE REGION. SCT SHWRS AND TSTMS WILL AFFECT MOST AREAS OVERNIGHT INTO SUN MRNG. SOME DRYING ON MON BUT WITH ANOTHER CHC OF SHWRS/TSTMS MAINLY SE. UPPER RIDGE THEN BUILDS INTO THE REGION FOR THE MIDDLE TO THE END OF THE WEEK WITH TEMPS WARMING TO ABOVE NORMAL BY THE MIDDLE OF THE WEEK. A RETURN OF SOME MSTR TO THE AREA WILL BRING SLIM CHCS OF LATE DAY STORMS TO THE REGION BY THE END OF THE WEEK. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. &&
Hazardous weather outlook, Aug 8, 10:00 AM MDT, 9 hours 20 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1000 AM MDT SAT AUG 8 2009 WYZ059>070-091600- CONVERSE-NIOBRARA-SOUTHWEST CARBON-NORTH CARBON-SNOWY RANGE- NORTH LARAMIE RANGE-LARAMIE VALLEY-LARAMIE RANGE-PLATTE-GOSHEN- CHEYENNE FOOTHILLS-PINE BLUFFS- 1000 AM MDT SAT AUG 8 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST WYOMING. .DAY ONE...TODAY AND TONIGHT SOME THUNDERSTORMS WILL FORM THIS AFTERNOON INTO THIS EVENING ACROSS MUCH OF THE REGION. A FEW OF THE STORMS MAY BECOME STRONG ENOUGH TO PRODUCE SMALL HAIL AND BRIEF HEAVY RAIN...MAINLY ALONG AND EAST OF THE LARAMIE RANGE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THERE IS A SLIGHT CHANCE OF LATE DAY THUNDERSTORMS...MAINLY EAST OF THE LARAMIE RANGE FROM SUNDAY THROUGH WEDNESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE NEZ001>003-019>021-054-055-091600- SIOUX-DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL- CHEYENNE- 1000 AM MDT SAT AUG 8 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE. .DAY ONE...TODAY AND TONIGHT SOME THUNDERSTORMS WILL FORM THIS AFTERNOON INTO THIS EVENING ACROSS MUCH OF THE REGION. A FEW OF THE STORMS MAY BECOME STRONG ENOUGH TO PRODUCE SMALL HAIL AND BRIEF HEAVY RAIN. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THERE IS A SLIGHT CHANCE OF LATE DAY THUNDERSTORMS...MAINLY EAST OF THE LARAMIE RANGE FROM SUNDAY THROUGH WEDNESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE
In the hours before
Special weather statement, Aug 8, 3:06 PM MDT, 4 hours 14 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 306 PM MDT SAT AUG 8 2009 WYZ059-067-069-082215- CONVERSE-PLATTE-CHEYENNE FOOTHILLS- INCLUDING THE CITIES OF...DOUGLAS...GLENROCK...WHEATLAND... GUERNSEY...CHEYENNE 306 PM MDT SAT AUG 8 2009 ...A FEW THUNDERSTORMS RUMBLING OVER SOUTHEAST WYOMING... AT 255 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED A FEW THUNDERSTORMS MAINLY ALONG AND NEAR INTERSTATE 25. ONE OF THESE STORMS WAS JUST NORTH OF CHEYENNE WITH ANOTHER NEAR GLENDO. OTHER STORMS NORTH OF CASPER WERE MOVING INTO NORTHWEST CONVERSE COUNTY. SMALL HAIL...WIND GUSTS NEAR 50 MPH AND BRIEF HEAVY RAIN WILL OCCUR WITH THESE STORMS AS THEY MOVE NORTHEAST AT 20 MPH. THUNDERSTORMS WILL BE INCREASING IN COVERAGE THROUGH THE REST OF THIS AFTERNOON. PEOPLE IN SOUTHEAST WYOMING SHOULD KEEP AN EYE ON THE SKY THIS AFTERNOON AND BE READY TO SEEK SHELTER SHOULD A STORM APPROACH. JLH
Special weather statement, Aug 8, 3:43 PM MDT, 3 hours 37 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 343 PM MDT SAT AUG 8 2009 WYZ060-082230- NIOBRARA- 343 PM MDT SAT AUG 8 2009 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN NIOBRARA COUNTY UNTIL 430 PM MDT... AT 340 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR LUSK...MOVING NORTHEAST AT 20 MPH. SMALL HAIL...HEAVY RAIN AND GUSTY WINDS AROUND 50 MPH ARE EXPECTED WITH THIS STORM. IF YOU ARE IN THE PATH OF THIS STORM...SEEK SHELTER IMMEDIATELY. GET INDOORS IF POSSIBLE AND STAY AWAY FROM WINDOWS. JLH
Special weather statement, Aug 8, 7:03 PM MDT, 17 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 703 PM MDT SAT AUG 8 2009 NEZ020-054-WYZ066-069-070-090230- BANNER-KIMBALL-LARAMIE RANGE-CHEYENNE FOOTHILLS-PINE BLUFFS- INCLUDING THE CITIES OF...HARRISBURG...KIMBALL...BUFORD... HORSE CREEK...CHEYENNE...PINE BLUFFS 703 PM MDT SAT AUG 8 2009 ...SCATTERED SHOWERS AND THUNDERSTORMS OVER THE AREA... NATIONAL WEATHER SERVICE RADAR IS INDICATING THAT SHOWERS AND THUNDERSTORMS WERE INCREASING IN COVERAGE ACROSS SOUTHERN LARAMIE COUNTY INTO THE FAR SOUTHWESTERN PORTION OF THE NEBRASKA PANHANDLE. THE ACTIVITY WILL LIKELY CONTINUE TO EXPAND IN COVERAGE AS IT MOVES NORTHEAST AT 20 MPH. LIGHTNING...BRIEF HEAVY RAIN AND GUSTY WINDS CAN BE EXPECTED FROM THE STRONGER STORMS WITH SOME SMALL HAIL POSSIBLE AS WELL.
The office that day
Everything else NWS Cheyenne, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 8:17 PM MDT | Areal Flood Advisory | CYS | Laramie | 2 hr |
Nearby
Severe Thunderstorm Warnings in Wyoming, 2009Every severe thunderstorm warning in 2009
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.