Alert archive / Nebraska / Tornado Warnings in 1999

Tornado Warning 46, NWS North Platte, NE

July 2, 1999Perkins County, Nebraska

NWS North Platte, NE issued this tornado warning at Jul 2, 1999, 7:00 PM MDT for Perkins County, Nebraska. It was in force for 50 min. 1 report 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: Jul 2, 1999, 7:00 PM MDT (01:00 UTC)
Expired: Jul 2, 1999, 7:50 PM MDT
In force: 50 min
Issued by: NWS North Platte, NE
Area: Whole counties

County Perkins County, NE

The radar

The North Platte radar (KLNX), 152 km from the middle of the area, began a volume at 01:00 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
Jul 2, 7:10 PM MDT	Thunderstorm Wind	Elsie, NE	Thunderstorm wind uprooted trees and picked up and smashed a grain bin.

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
Jul 2, 3:00 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 1.0 hours before the alert went out and 93 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: 5849 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 1210 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 152 m²/s²
Significant tornado parameter: 3.4
Supercell composite: 25.1

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 tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS North Platte, NE wrote its last area forecast discussion before this tornado warning went out at Jul 2, 1:45 PM MDT, 5 hours 15 minutes earlier.

Area forecast discussion, Jul 2, 1:45 PM MDT, 5 hours 15 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
245 PM CDT FRI JUL 2 1999

...FORECAST CHALLENGES ARE THUNDERSTORM CHANCES TONIGHT THEN
TEMPERATURES...

SURFACE WARM FRONT HAS LIFTED NORTH THROUGH MOST OF CWFA PUSHING
DEWPOINTS INTO LOWER TO MID 70S SE OF AXIS FROM VTN TO IML. WARM
FRONT EXTENDED SW TO LOW IN FAR SE WY. CI FROM CONVECTION OVER MTNS
HAS KEPT TEMPERATURES A BIT COOLER THAN EXPECTED SO FAR. VERY
UNSTABLE BUT CAPPED ATMOSPHERE IS OVER AREA FROM MCK TO VTN.
FORECAST PROBLEM IS WHERE CONVECTION WILL DEVELOP TONIGHT. NEAREST
UPSTREAM TSRA ACTIVITY AT 19Z WAS FROM CENTRAL CO TO SW KS
ASSOCIATED WITH WEAK SHORTWAVE MOVING OUT OF NEW MEXICO. WITHOUT
STRONG DYNAMICS...WILL LEAVE IN 20 PERCENT POPS FOR OVERNIGHT
THUNDERSTORMS ACROSS FORECAST AREA...EXCEPT IN THE NE. IN ONL TO ANW
GROUP THE PROXIMITY TO THE WARM FRONT AND UPSTREAM SURFACE DEWPOINTS
IN MID 70S WILL WARRANT KEEPING POPS A BIT HIGHER AT 30 PERCENT.
THIS AREA WILL ALSO NEED TO BE WATCHED FOR POTENTIAL HEAVY RAINFALL
AS FLASH FLOOD GUIDANCE VALUES THERE ARE LOW DUE TO RECENT RAINFALL.

ETA HAD BEST RUN TO RUN MODEL CONSISTENCY AND WAS BETTER THAN NGM
WITH SURFACE DEWPOINTS. IT ALSO HAD GOOD HANDLE ON VORT MAX AT 18Z
MOVING OUT OF SW AND THUS MODEL OF CHOICE. NOT A LOT OF DIFFERENCE
BETWEEN MODELS IN HANDLING OF MAJOR FEATURES.

WENT CLOSER TO WARMER FAN TEMPERATURES FOR HIGHS SAT AND SUNDAY WITH
OVERNIGHT LOWS CLOSE TO GUIDANCE. EXPECT CAP TO REMAIN STRONG ENOUGH
TO LEAVE OUT MENTION OF TSRA SATURDAY AND WILL KEEP FORECAST DRY AND
HOT WITH BREEZY CONDITIONS MENTIONED IN MOST ZONES. HOT AND DRY
TREND WILL PERSIST SUNDAY WITH SURFACE TROUGH HANGING TOUGH OVER
WESTERN NE. IN EXTENDED...93P GUIDANCE NOW HAS HIGHS ONLY IN LOWER 80S
FOR MONDAY WITH MRF SHOWING DRY COLD FRONT TO PUSH INTO FORECAST
AREA AND WILL CUT HIGHS BACK SOME FOR MONDAY AND ADD CHANCE OF
THUNDERSTORMS FOR WEDNESDAY WITH SHORTWAVE MOVING OVER RIDGE THROUGH
AREA.

.LBF...NONE.
SHEETS

In the hours before

Local storm report, Jul 2, 6:22 PM MDT, 38 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE  NORTH PLATTE NE
722 PM CDT FRI JUL 2 1999

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

0715 PM    5 WNW HAMLET              NE   0.75 INCH HAIL
07/02/99   HAYES

FWM

The office that day

Everything else NWS North Platte, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 2, 6:06 PM MDT	Severe Thunderstorm Warning	LBF	Chase, Hayes	64 min
Jul 2, 6:28 PM MDT	Severe Thunderstorm Warning	LBF	Chase	62 min
Jul 2, 6:46 PM MDT	Severe Thunderstorm Warning	LBF	Perkins	59 min
Jul 2, 7:09 PM MDT	Severe Thunderstorm Warning	LBF	Lincoln	61 min
Jul 2, 7:43 PM MDT	Tornado Warning	LBF	Keith, Lincoln, McPherson	47 min
Jul 2, 8:15 PM MDT	Severe Thunderstorm Warning	LBF	Custer, Lincoln, Logan	60 min
Jul 2, 8:15 PM MDT	Severe Thunderstorm Warning	LBF	Thomas	60 min
Jul 2, 8:29 PM MDT	Severe Thunderstorm Warning	LBF	Hooker, McPherson	61 min
Jul 2, 8:43 PM MDT	Severe Thunderstorm Warning	LBF	Sheridan	62 min
Jul 2, 9:10 PM MDT	Tornado Warning	LBF	Sheridan	45 min
Jul 2, 9:20 PM MDT	Severe Thunderstorm Warning	LBF	Cherry	60 min
Jul 2, 9:33 PM MDT	Severe Thunderstorm Warning	LBF	Cherry	62 min
Jul 2, 9:56 PM MDT	Tornado Warning	LBF	Cherry	64 min

Nearby

Tornado Warnings in Nebraska, 1999 Every tornado warning in 1999 Tornadoes 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.