Alert archive / Wyoming / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 42, NWS Cheyenne, WY

June 29, 2001Laramie County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jun 29, 2001, 6:27 PM MDT for Laramie County, Wyoming. It was in force for 63 min. 3 reports came from inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.

The facts

Issued: Jun 29, 2001, 6:27 PM MDT (00:27 UTC)
Expired: Jun 29, 2001, 7:30 PM MDT
In force: 63 min
Issued by: NWS Cheyenne, WY
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 8 km from the middle of the area, began a volume at 00:31 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
Jun 29, 6:34 PM MDT	Hail 0.75	Cheyenne, WY
Jun 29, 6:48 PM MDT	Hail 0.75	Federal, WY
Jun 29, 7:30 PM MDT	Hail 0.75	Cheyenne, WY

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 0.5 hours before the alert went out and 201 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 18 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 3829 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 24 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS55 KCYS 300029
SVRCYS

WYC021-300130-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
627 PM MDT FRI JUN 29 2001

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN LARAMIE COUNTY IN SOUTHEAST WYOMING
  THIS INCLUDES THE CITY OF CHEYENNE

* UNTIL 730 PM MDT

* AT 621 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED SEVERAL
  SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HALF OF LARAMIE
  COUNTY...DRIFTING NORTHEAST AT 10 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE WARREN AF BASE...PINE
  BLUFFS...NORTH CHEYENNE...FEDERAL...CARPENTER AND ALBIN

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY SHELTER
AWAY FROM CREEK BEDS AND OTHER FLOOD-PRONE AREAS. REMEMBER...A SEVERE
THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...DAMAGING WINDS IN
EXCESS OF 55 MPH...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

LAT...LON 4134 10528 4101 10527 4102 10408 4142 10407

DAUGHERTY
WCJIN-WYSE

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 Jun 29, 2:37 PM MDT, 3 hours 50 minutes earlier.

Area forecast discussion, Jun 29, 2:37 PM MDT, 3 hours 50 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
237 PM MDT FRI JUN 29 2001

NORTHERN PANHANDLE CONTINUES TO DESTABLIZE WITH SURPRISINGLY
"JUICEY" DEWPOINTS EXTENDING FROM SOUTH-CENTRAL SD TO IEN/CDR WITH
AROUND 70F. SURFACE BOUNDARY...WHICH CROSSED WY/CO AND NEB/CO AROUND
NOON...HAS SUPPRESSED CONVECTION IMMEDIATELY BEHIND IT. STRONG
STORMS FIRING BLACK HILLS WITH INCREASING CONVECTION INTO
EAST-CENTRAL WY. EARLIER SWOMCD CONFIRMS SUSPICION OF SEVERE WATCH
FOR NORTHERN PANHANDLE AT ANY TIME. APPEARS CWA WILL BE LOCKED INTO
RISK SEVERE THROUGH WEEKEND...MAINLY LARAMIE MOUNTAINS EASTWARD.
BOTH ETA/AVN INDICATE INCREASING QPF AFTER MIDNIGHT AS CONVECTION
OFF BIG HORNS OF NORTH-CENTRAL WY AND BLACK HILLS MOVES DOWNSTREAM
TONIGHT. ETA HAS INTENSE...CONVECTIVELY INDUCED...VORTICITY CENTER
OVER WEST-CENTRAL SD AT 12 UTC/6 AM SAT WITH TAIL OF WAVE EXTENDING
THROUGH SOUTHEAST CORNER WY. WILL GO WITH HIGH SCATTERED-TYPE POP
FORECAST EAST OF LARAMIE MOUNTAINS TONIGHT. TEMP/POP FORECAST SAT
THROUGH SUN LOOKS LIKE A BROKEN RECORD WITH PREDOMINATELY 85-95F
HIGHS AND 20-30 PERCENT POPS. POPS MORE SEASONAL SOUTH-CENTRAL. MEAN
RIDGE AXIS NORTHEAST/SOUTHWEST THROUGH SOUTHEAST CORNER WY ATTM
SHIFTS SOUTH AND DE-AMPLIFIES THROUGH 60 HRS/6 PM SUN. REMAINS OF
AXIS WILL EXTEND EAST FROM FOUR CORNER UPPER HIGH THEN. FLAT
RIDGGING OR NEARLY ZONAL FLOW NORTH-NORTHEAST FROM UPPER HIGH
THROUGH CENTRAL WY SUN AFTERNOON. MODELS CONTINUE IDEA OF GENERALLY
WEAK SOURCES OF UPPER DIVERGENCE EACH 12 HRS DURING WEEKEND. ONE
OVER WESTERN SD SAT MORNING...AND ANOTHER THROUGH CENTRAL OR SOUTHEAST
WY SUN MORNING COULD PRODUCE ISOLATED LATE NIGHT/MORNING SHOWERS/
T-STORMS.

.EXTENDED DISCUSSION...MEAN UPPER LEVEL RIDGE GRADUALLY RETROGRADES
WITH TIME LEAVING OUR CWA IN NW FLOW ALOFT. BETTER CHANCE OF SHOWERS
AND THUNDERSTORMS EACH DAY IN THIS FLOW PATTERN. CANADIAN HIGH
PRESSUTRE BUILDS SOUTH INTO THE HIGH PLAINS BY THE END OF THE WEEK
WITH COOLER TEMPERATURES EXPECTED FOR THE LAST PART OF THE WORK WEEK.

.CYS...
WY...NONE.
NE...NONE.

COX/STARK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 29, 7:32 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	43 min
Jun 29, 8:14 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	61 min
Jun 29, 9:19 PM MDT	Severe Thunderstorm Warning	CYS	Goshen	56 min
Jun 29, 9:47 PM MDT	Severe Thunderstorm Warning	CYS	Platte	43 min
Jun 29, 10:44 PM MDT	Severe Thunderstorm Warning	CYS	Platte	46 min
Jun 30, 2:43 PM MDT	Tornado Warning	CYS	Laramie	32 min
Jun 30, 3:14 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	46 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2001 Every severe thunderstorm warning in 2001

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.