Alert archive / Nebraska / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 229, NWS North Platte, NE

September 1, 1999McPherson County, Nebraska

NWS North Platte, NE issued this severe thunderstorm warning at Sep 1, 1999, 9:55 PM CDT for McPherson County, Nebraska. It was in force for 45 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
Sep 1, 1999, 9:55 PM CDT (02:55 UTC)
Expired
Sep 1, 1999, 10:40 PM CDT
In force
45 min
Issued by
NWS North Platte, NE
Area
Whole counties

County McPherson County, NE

The radar

The North Platte radar (KLNX), 59 km from the middle of the area, began a volume at 02:54 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

TimeReportWhereRemark
Sep 1, 10:05 PM CDTHail 0.75Tryon, 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 nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 2.9 hours before the alert went out and 62 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, N. Platte/Lee Bi, NE at 00:00Z on 1999-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1701 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, N. Platte/Lee Bi, NE at 00:00Z on 1999-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 square meters per square second.1939Sfc1 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
1701 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
1704 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 North Platte, NE wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 1, 12:43 PM CDT, 9 hours 12 minutes earlier.

Area forecast discussion, Sep 1, 12:43 PM CDT, 9 hours 12 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1240 PM CDT WED 1999

...FORECAST CHALLENGE CONTINUES TO BE POPS AND TEMPS...

SCT MID-LVL INSTABILITY AND -SHRA OVER MUCH OF CWA FROM IML TO VTN AT
15Z. LOW CIRC CENTERED OVER LBF AT 15Z IN ASSOC WITH SFC TROF. SFC FRONT
FM NR IML TO ANW. ETA SEEMS TO BE FAIRLY ON TRACK WITH PREVIOUS RUNS.

NGM PRECIPITATION FIELDS LOOK OVERDONE (AS THEY DID YESTERDAY AS
WELL...AND PROVED TO BE SO.) ALL MODELS (INCLUDING RUC AND MESOETA)
HOLD PRECIPITATION BACK TO THE NORTHWEST OF LBF UNTIL TONIGHT. ETA
VORTICITY REMAINS FAIRLY CHANNELIZED UNTIL THIS AFTERNOON...BUT SENDS
VORT MAX AFTER VORT MAX THROUGH THE FLOW THRU PD. DELINIATION BETWEEN
AREAS THAT GET WEATHER AND THOSE THAT DONT MAY BE SHARP DUE TO
AMPLIFICATION...AND TIGHT GRADIENT ALOFT. WE ARE NEAR THE INFLECTION
POINT...SO EASTERN ZONES WILL HAVE GREATEST AMOUNT OF UNCERTAINTY.
SWODY1 INDICATES AREA WILL BE IN THE RRQ OF JET. MORNING SOUNDING
PRECIPITABLE WATER LOOKS ABOUT AVERAGE FOR LBF AT .96 INCHES. CAP
STRENGTH STRONG OVER LBF...BUT IS TO ERODE WITH FROPA. CONVECTION TO
BEGIN ALONG FOOTHILLS AND SPREAD FROM WEST TO EAST SEEMS GENERAL
CONSENSUS. WILL GO WITH HIGHER POPS (IF PCPN ISNT ALREADY GOING BY ZONE
ISSUANCE TIME) FOR WESTERN ZONES. LOWEST POPS FOR ONL GROUPING THIS
EVE/TNT.

2ND/3RD PERIOD...ROUND TWO OF CONVECTIVE WEATHER THURSDAY AFTERNOON.
NEARLY STATIONARY FRONT SHIFTS SOMEWHAT NORTHEAST.  ALMOST ENTIRE CWA
IN DAY 2 SLIGHT RISK AS UPPER LEVEL TROF SHIFTS EAST. AM NOT GOING TO
STRAY FAR FROM FWC GUIDANCE WHERE ABLE TO USE. MRF GUIDANCE LOOKS TOO
COOL. WILL GO WITH 30 OR 40 POPS MOST AREAS AGAIN FOR THURSDAY. FRIDAY
IS SORT OF A BIG QUESTION MARK WITH THE MRF RUNNING COLD. THINK ILL
LEAVE POPS OUT FOR NOW EXCEPT FOR MAYBE MENTION IN NORTHWEST
COUNTIES...WORDED LATE AFTERNOON.

IN THE EXTENDED...MODELS CANT DECIDE IF THE TROF OVER THE WEST WILL
CUT OFF AFTER SATURDAY OR NOT.  MRF CUTS OFF THE LOW AND LIFTS IT
NORTHEAST.  ECMWF BRIEFLY CLOSES THE LOW FRIDAY BUT THEN OPENS IT UP
AGAIN BY SATURDAY MORNING...GIVING IT A NEGATIVE TILT WHILE LIFTING IT
NORTHEAST. PROBABLY THE SAFEST THING TO DO IS GO WITH CHANCES EACH DAY.
EVEN IF THE MRF WERE TO VERIFY...I HAVE A HARD TIME BELIEVING THE 64
DEGREES FOR A HIGH SATURDAY AT LBF SINCE THE MRF ALSO HAS SFC RIDGING
TAKING PLACE AT THAT TIME. FEEL HIGHS IN THE UPPER 70S TO MID 80S WILL
LIKELY COVER IT...WITH LOWS IN THE 50S AND 60S.

.LBF...NONE.

SLM

In the hours before

Local storm report, Sep 1, 7:05 PM CDT, 2 hours 50 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE  NORTH PLATTE NE
705 PM CDT WED SEP 1 1999

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

0700 PM    5 W ANTIOCH               NE   0.75 INCH HAIL
09/01/99   SHERIDAN

DP
Local storm report, Sep 1, 8:13 PM CDT, 1 hour 42 minutes before
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Local storm report, Sep 1, 8:37 PM CDT, 1 hour 18 minutes before
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Local storm report, Sep 1, 8:37 PM CDT, 1 hour 18 minutes before
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Local storm report, Sep 1, 9:14 PM CDT, 41 minutes before
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Local storm report, Sep 1, 9:33 PM CDT, 22 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 7:35 PM CDTSevere Thunderstorm WarningLBFGarden60 min
Sep 1, 7:46 PM CDTTornado WarningLBFSheridan59 min
Sep 1, 8:08 PM CDTTornado WarningLBFCherry62 min
Sep 1, 8:33 PM CDTSevere Thunderstorm WarningLBFGrant62 min
Sep 1, 8:44 PM CDTSevere Thunderstorm WarningLBFCherry61 min
Sep 1, 9:09 PM CDTSevere Thunderstorm WarningLBFArthur66 min
Sep 2, 6:06 PM CDTFlash Flood WarningLBFChase, Hayes, Lincoln, Perkins114 min
Sep 2, 6:50 PM CDTSevere Thunderstorm WarningLBFHayes50 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 1999Every 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.