Tornado Warning 1, NWS Sioux Falls, SD

Issued

May 3, 1999, 9:49 PM CDT (02:49 UTC)

Expired

May 3, 1999, 10:20 PM CDT

In force

31 min

Issued by

NWS Sioux Falls, SD

Area

Whole counties

County Yankton County, SD

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.

999 
WFUS1 KFSD 040248 RRA
TORFSD
SDC135-040320-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
949 PM CDT MON MAY 3 1999

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHERN YANKTON COUNTY IN SOUTHEASTERN SOUTH DAKOTA

* UNTIL 1020 PM CDT

* AT 946 PM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A TORNADO 8 MILES WEST OF YANKTON... MOVING NORTH AT 30 MPH.

* THE TORNADO IS EXPECTED TO BE NEAR...
  YANKTON                  AROUND 955 PM CDT
  UTICA                    AROUND 1005 PM CDT

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING
WHICH WAS IN EFFECT FOR YANKTON COUNTY UNTIL 955 PM CDT.

THIS STORM HAS PRODUCED A TORNADO IN NORTHERN NEBRASKA. GO TO THE
BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR.

NWS Sioux Falls, SD wrote its last area forecast discussion before this tornado warning went out at May 3, 3:45 PM CDT, 6 hours 4 minutes earlier.

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
345 PM CDT MON MAY 3 1999

VERY MESSY NXT FEW DAYS WITH UPPER LOW EVENTUALLY HOVERING OVER THE
CNTRL AND NRN PLAINS BY THE EXTENDED FCST. IN THE FIRST PRD TSTMS
FIRING OF IN NW NEBRASKA AND SW SD THIS AFTN FOR THE MOST PART WL
REMAIN W OF CWA THIS EVE.  ANOTHER WAVE...ALONG WITH 850 MB LOW
LEVEL JET WL BRING ANOTHER CHC OF PCPN LATER TNGT. BY LATER TNGT
ATMOSPHERE LESS UNSTABLE AND NOT TOO CONCERNED ABT SEVERE WX IN THE
FSD CWA TNGT.

HOWEVER...AHEAD OF ADVANCING CDFNT AND GOOD DRY/MOIST BOUNDARY
SETTING UP ANOTHER CHC OF TSTMS TO DEVELOP IN THE AFTN FOR MOST OF
CWA. CONFIDENCE IN TIMING OF DEVELOPMENT WEIGHS HEAVILY ON
ASSUMPTION THAT PCPN WL END IN THE MRNG HOURS AND ALLOW ATMOSPHERE
TO RECOVER. CAPES OF 1000 TO 1500 J/KG FM MODIFIED FCST SOUNDINGS
INDICATED LATE TUE AFTN WL BRING A SLGHT RISK OF SVR WX FOR MUCH OF
THE CWA TUE WITH AGREES WITH CURRENT SPC DAY TWO RISK.

AS WE MOVE INTO THE EXTENDED...MRF INDICATING 500 MB LOW ALONG WITH
SIGNIFCANT COLD POOL TO SETUP IN THE REGION. CHC FOR PCPN IN MOST OF
THE EXTENDED. LOOKING AT VERY COOL MRF B.L. TEMPS PROGGED THROUGH
THE EXTENDED AND EXPECTED CLD COVER...THE FMR LOOKS WAY TOO WARM.
HAVE LOWERED TEMPS ROUGHLY 10 DEGREES FM FMR.

.FSD...NONE.

BR

Tornado Warnings in South Dakota, 1999Every tornado warning in 1999Tornadoes in 1999

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.