Alert archive / Nebraska / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 112, NWS Cheyenne, WY

September 3, 1999Banner County, Scotts Bluff County, Sioux County, Nebraska

NWS Cheyenne, WY issued this severe thunderstorm warning at Sep 3, 1999, 6:14 PM MDT for Banner County, Scotts Bluff County, Sioux County, Nebraska. It was in force for 61 min. 3 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Sep 3, 1999, 6:14 PM MDT (00:14 UTC)
Expired: Sep 3, 1999, 7:15 PM MDT
In force: 61 min
Issued by: NWS Cheyenne, WY
Area: Whole counties

Counties Banner County, NE, Scotts Bluff County, NE, Sioux County, NE

The radar

The Cheyenne radar (KCYS), 127 km from the middle of the area, began a volume at 00:18 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
Sep 3, 6:31 PM MDT	Tornado F0	Morrill, NE	Brief tornado reported by public
Sep 3, 6:44 PM MDT	Tornado F0	Agate, NE	Brief tornado spotted by public neat the county line
Sep 3, 7:25 PM MDT	Hail 0.75	Harrisburg, NE	3/4 inch hail reported 9 miles south of McGrew, NE

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 watch it was issued in

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

Issued	Product	Office	Lasted
Sep 3, 4:15 PM MDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 0.2 hours before the alert went out and 236 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: 542 J/kg
Mixed-layer CIN: -117 J/kg
Mixed-layer LCL: 1906 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: 173 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Sep 3, 2:30 PM MDT, 3 hours 44 minutes earlier.

Area forecast discussion, Sep 3, 2:30 PM MDT, 3 hours 44 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
230 PM MDT FRI SEP 3 1999

UPPER LOW MOVING INTO SOUTHWEST ID AT THE MOMENT IN LINE WITH SIMILAR
MODELS. ASSOCIATED CONVECTION OVER WESTERN WY LATE THIS MORNING WAS
MORE IN LINE WITH THE ETA VORTICITY PROG.  UPPER LOW FORECASTED TO LIFT
EAST NORTHEAST ACROSS EASTERN ID/WRN MT THIS EVENING...CONTINUING EAST
ACROSS WY AND MT LATER TONIGHT INTO SAT MORNING THEN INTO THE DAKOTAS
BY SAT EVENING.  BEST DYNAMICS FAVOR WEST WY THIS PM. HOWEVER RIGHT
ENTRANCE OF JET SEGMENT PASSES OVER SE END WY THIS EVENING TO HELP
UPWARD VERTICAL VELOCITIES A TAD. ALSO WILL BE A FAVORABLE WIND PROFILE
FOR A FEW POSSIBLE SUPER CELLS OVER THE EAST END OF THE CWA.  CAPES TO
VARY BETWEEN 400 TO 1600 J/KG WITH LIS FROM -2 TO -6 OVER THE CWA THIS
AFTN/EVE...WITH HIGHEST VALUES ACROSS EXTREME SE END OF THE CWA. BEST
COLD AIR ADVECTION TO SPREAD OVER THE AREA TONIGHT WHICH WILL HELP TO
MAINTAIN AN UNSTABLE ATMOSPHERE THROUGH THE NIGHT.  WILL CONTINUE HIGH
POPS IN THE LIKELY CATEGORY FOR MUCH OF THE CWA TONIGHT WITH A FEW
STRONG STORMS POSSIBLE OVER THE SE END OF THE CWA LATE THIS AFTERNOON
AND EVENING TIL AROUND SUNSET.

UPPER TROF TO CONTINUE DOMINATING OUR WEATHER THROUGH SATURDAY WITH
BEST DYNAMICS AND POPS SHIFTING TO THE NE CLOSER TO TO THE UPPER LOW
CIRCULATION.  STILL ENOUGH OF A VORTICITY LOBE FORECASTED TO IMPACT THE
CHEYENNE CWA TO SUPPORT SCATTERED POPS SAT.  WILL ALSO HAVE A SURFACE
HIGH PRESSURE MOVING SOUTH THROUGH MONTANA INTO NORTHEAST WY DURING THE
DAY TO PROVIDE A NORTH TO NORTHEAST UPSLOPE FLOW INTO EASTERN WY WHICH
WILL HELP KEEP TEMPS COOL AND JUICE UP THE LOW LEVELS . UPSLOPE FLOW TO
BECOME MORE EAST TO SOUTHEAST SATURDAY NIGHT.  WITH DECENT LOW LEVEL
MOISTURE AVAILABLE AND UPSLOPE WINDS...SHOULD SEE DEVELOPMENT OF LOW
CLOUDS AND FOG OVER THE CWA EAST OF THE LARAMIE RANGE SAT NIGHT.

UPPER TROF MOVES EAST ACROSS THE DAKOTAS SUN WITH HEIGHTS REBOUNDING
IN WY RETURNING A DRIER NORTHWEST FLOW ALOFT.  THE SURFACE HIGH SLIPS
EAST OF WY AND THE NEBRASKA PANHANDLE SUNDAY TO RETURN A NORTHWEST
DOWNSLOPE FLOW TO THE CWA SUNDAY FOR A DRIER BUT COOL AIRMASS OVER THE
CWA.

HAVE LEANED TO COOLER FAN TEMPERATURE GUIDANCE.

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

PAL

In the hours before

Local storm report, Sep 3, 1:54 PM MDT, 4 hours 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE  CHEYENNE WY
154 PM MDT FRI SEP 3 1999

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0215 PM    15 NE CHUGWATER           WY   1.50 INCH HAIL
09/01/99   PLATTE                         DAMAGED ROOF BROKE WINDOW
                                          KILLED BIRDS

0325 PM    5 NE HAWK SPRINGS         WY   61 MPH WIND GUST
09/01/99   GOSHEN

GRIFFITH

Local storm report, Sep 3, 1:57 PM MDT, 4 hours 17 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE  CHEYENNE WY
157 PM MDT FRI SEP 3 1999

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0230 PM    13 NW HARRISBURG          NE   TORNADO
09/02/99   BANNER                         ON GROUND 230 PM TO 232
                                          PM NO DAMAGE

GRIFFITH

Local storm report, Sep 3, 2:32 PM MDT, 3 hours 42 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE  CHEYENNE WY
232 PM MDT FRI SEP 3 1999

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0430 PM    13 NW HARRISBURG          NE   TORNADO
09/02/99   BANNER                         ON GROUND 430 PM TO 432 PM
                                          NO DAMAGE

GRIFFITH/STARK

Local storm report, Sep 3, 2:32 PM MDT, 3 hours 42 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE  CHEYENNE WY
232 PM MDT FRI SEP 3 1999

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0430 PM    13 NW HARRISBURG          NE   TORNADO
09/02/99   BANNER                         ON GROUND 430 PM TO 432 PM
                                          NO DAMAGE

GRIFFITH/STARK

Special weather statement, Sep 3, 4:13 PM MDT, 2 hours 1 minute before

NEZ001>003-019>021-054-055-WYZ060-067>070-040400-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
413 PM MDT FRI SEP 3 1999

...TORNADO WATCH FOR PARTS OF SOUTHEAST WYOMING AND WESTERN
NEBRASKA PANHANDLE...

A TORNADO WATCH HAS BEEN POSTED FOR PARTS OF SOUTHEAST WYOMING
AND THE WESTERN NEBRASKA PANHANDLE UNTIL 10 PM MDT.

IN WYOMING...THE WATCH INCLUDES SOUTHERN NIOBRARA...PLATTE...GOSHEN
AND LARAMIE COUNTIES.  IN THE WESTERN PANHANDLE...THE WATCH
INCLUDES...SIOUX...DAWES...BOX BUTTE...SCOTTS BLUFF...BANNER...
MORRILL...KIMBALL AND CHEYENNE COUNTIES PLUS COUNTIES FARTHER TO THE
EAST.

A MOIST SOUTHWEST FLOW ALOFT WILL PERSIST OVER SOUTHEAST WYOMING AND
THE NEBRASKA PANHANDLE THIS AFTERNOON AND EVENING WITH AN EXTREMELY
UNSTABLE AIRMASS.  THE CONFIGURATION OF LOW LEVEL AND UPPER WINDS IN
THE ATMOSPHERE WILL MAKE THE THREAT OF TORNADOES POSSIBLE WITH ANY
SEVERE THUNDERSTORMS.

COX

WCJIN-WYSE-WYNE

Special weather statement, Sep 3, 4:13 PM MDT, 2 hours 1 minute before

NEZ001>003-019>021-054-055-WYZ060-067>070-040400-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
413 PM MDT FRI SEP 3 1999

...TORNADO WATCH FOR PARTS OF SOUTHEAST WYOMING AND WESTERN
NEBRASKA PANHANDLE...

A TORNADO WATCH HAS BEEN POSTED FOR PARTS OF SOUTHEAST WYOMING
AND THE WESTERN NEBRASKA PANHANDLE UNTIL 10 PM MDT.

IN WYOMING...THE WATCH INCLUDES SOUTHERN NIOBRARA...PLATTE...GOSHEN
AND LARAMIE COUNTIES.  IN THE WESTERN PANHANDLE...THE WATCH
INCLUDES...SIOUX...DAWES...BOX BUTTE...SCOTTS BLUFF...BANNER...
MORRILL...KIMBALL AND CHEYENNE COUNTIES PLUS COUNTIES FARTHER TO THE
EAST.

A MOIST SOUTHWEST FLOW ALOFT WILL PERSIST OVER SOUTHEAST WYOMING AND
THE NEBRASKA PANHANDLE THIS AFTERNOON AND EVENING WITH AN EXTREMELY
UNSTABLE AIRMASS.  THE CONFIGURATION OF LOW LEVEL AND UPPER WINDS IN
THE ATMOSPHERE WILL MAKE THE THREAT OF TORNADOES POSSIBLE WITH ANY
SEVERE THUNDERSTORMS.

COX

WCJIN-WYSE-WYNE

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 3, 6:14 PM MDT	Severe Thunderstorm Warning	CYS	Kimball	61 min
Sep 3, 6:35 PM MDT	Tornado Warning	CYS	Scotts Bluff, Sioux	35 min
Sep 3, 7:21 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Morrill	34 min
Sep 3, 6:29 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	31 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 1999 Every severe thunderstorm warning in 1999

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.