Alert archive / South Dakota / Tornado Warnings in 1999
Tornado Warning 18, NWS Aberdeen, SD
NWS Aberdeen, SD issued this tornado warning at Jul 22, 1999, 6:38 PM CDT for McPherson County, South Dakota. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jul 22, 1999, 6:38 PM CDT (23:38 UTC)
- Expired
- Jul 22, 1999, 7:10 PM CDT
- In force
- 32 min
- Issued by
- NWS Aberdeen, SD
- Area
- Whole counties
County McPherson County, SD
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 22, 5:15 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Aberdeen, SD (KABR), launched 12:00Z, 11.6 hours before the alert went out and 116 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.
- Mixed-layer CAPE
- 1958 J/kg
- Mixed-layer CIN
- -260 J/kg
- Mixed-layer LCL
- 1086 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 140 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KABR 222339 RRA TORABR SDC089-230010- BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE ABERDEEN SD 638 PM CDT THU JUL 22 1999 THE NATIONAL WEATHER SERVICE IN ABERDEEN HAS ISSUED A * TORNADO WARNING FOR... SOUTHEASTERN MCPHERSON COUNTY IN NORTHEASTERN SOUTH DAKOTA * UNTIL 710 PM CDT * AT 635 PM CDT... ABERDEEN DOPPLER RADAR AND SPOTTER REPORTS INDICATED A TORNADO 31 MILES NORTHWEST OF ABERDEEN OR 6 MILES WEST OF LEOLA MOVING EAST AT 10 MPH. * THE TORNADO WILL BE JUST NORTH OF PLAINVIEW COLONY AT 655 PM CDT. GO TO THE BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR! DH/JCB &
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 Aberdeen, SD wrote its last area forecast discussion before this tornado warning went out at Jul 22, 3:19 PM CDT, 3 hours 19 minutes earlier.
Area forecast discussion, Jul 22, 3:19 PM CDT, 3 hours 19 minutes before
AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 315 PM CDT THU JULY 22 1999 TSRAS ALREADY BREAKING THROUGH THE CAP ALONG SFC TROUGH EXTENDING ACROSS C AND NC SD LATE THIS AFTERNOON. SATELLITE DERIVED PRODUCTS SHOWED A VERY UNSTABLE AIRMASS ACROSS MOST OF THE ABR CWA WITH LIS DOWN TO -12 AND CAPES OF 4-6 THOUSAND. HIGH DWPTS IN THE MID TO UPPER 70S AND TEMPS IN THE 90S TO OVER 100 WERE WEAKENING THE CAP. SATELLITE PRODUCTS CINH SHOWED THE CAP WEAKENING THE FASTEST IN C SD WHERE TSRAS ARE PRESENTLY DEVELOPING. ALSO...A GOOD THETA-E RIDGE IS IN PLACE OVER NE SD AND WC MN. THEREFORE...AS TROUGH MOVES THROUGH TONIGHT...THERE WILL BE A CHANCE OF TSRAS OVER ALL OF THE AREA. FRIDAY SHOULD AGAIN BE A HOT DAY WITH LESS HUMIDITY AS DWPTS FALL INTO THE 60S. FOR FRIDAY NIGHT AND SATURDAY...MDLS SHOW UPPER RIDGE HOLDING IN STRONG WITH UPPER DISTURBANCES ROLING OVER IT. DUE TO THE TIMING AND STRENGTH OF THESE WAVES...WILL LEAVE OUT POPS FOR THE CWA FOR FRIDAY NIGHT AND SATURDAY. FOR SUNDAY THROUGH TUESDAY...THE WEATHER PATTERN CHANGES VERY LITTLE...EXCEPT FOR ON MONDAY ACROSS NE SD AND WC MN WHERE THE AVN SHOWS A S/W MOVING OVER THE AREA...SO WILL PUT IN A CHANCE OF TSRAS HERE. DID NOT STRAY MUCH FROM GUIDANCE TEMPS. .ABR...NONE. MOHR
The office that day
Everything else NWS Aberdeen, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 22, 3:59 PM CDT | Severe Thunderstorm Warning | ABR | Lyman | 46 min |
| Jul 22, 4:59 PM CDT | Severe Thunderstorm Warning | ABR | Hughes, Stanley | 46 min |
| Jul 22, 5:17 PM CDT | Severe Thunderstorm Warning | ABR | Sully | 48 min |
| Jul 22, 5:29 PM CDT | Tornado Warning | ABR | Potter, Sully | 36 min |
| Jul 22, 6:01 PM CDT | Flash Flood Warning | ABR | Sully | 2 hr |
| Jul 22, 6:18 PM CDT | Tornado Warning | ABR | McPherson | 32 min |
| Jul 22, 6:50 PM CDT | Tornado Warning | ABR | Edmunds | 35 min |
Nearby
Tornado Warnings in South Dakota, 1999Every tornado warning in 1999Tornadoes 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; the sounding from the Mesonet's radiosonde archive.