Alert archive / Missouri / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 39, NWS St. Louis, MO

February 27, 1999Jefferson County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Feb 27, 1999, 12:39 PM CST for Jefferson County, Missouri. It was in force for 46 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
Feb 27, 1999, 12:39 PM CST (18:39 UTC)
Expired
Feb 27, 1999, 1:25 PM CST
In force
46 min
Issued by
NWS St. Louis, MO
Area
Whole counties

County Jefferson County, MO

The radar

The St Louis radar (KLSX), 50 km from the middle of the area, began a volume at 18:40 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.

The watch it was issued in

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

IssuedProductOfficeLasted
Feb 27, 12:15 PM CSTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 6.7 hours before the alert went out and 268 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, Lincoln, IL at 12:00Z on 1999-02-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 107 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, Lincoln, IL at 12:00Z on 1999-02-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 275 square meters per square second.193958Sfc1 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
107 J/kg
Mixed-layer CIN
-160 J/kg
Mixed-layer LCL
635 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
275 m²/s²
0-3 km storm-relative helicity
325 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

999 
WUUS1 KSTL 271841 RRA
SVRSTL
MOC099-271925-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
1239 PM CST SAT FEB 27 1999

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN JEFFERSON COUNTY IN EAST CENTRAL MISSOURI

* UNTIL 125 PM CST

* AT 1237 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 5 MILES SOUTHWEST OF DE SOTO... MOVING
  NORTHEAST AT 30 MPH.

* LOCATIONS THAT WILL BE AFFECTED...
  DE SOTO
  CRYSTAL CITY



THE PRIMARY SEVERE WEATHER THREAT IS DAMAGING HAIL. LARGE HAIL CAN
CAUSE EXTENSIVE PROPERTY DAMAGE AN SERIOUS INJURY TO PEOPLE CAUGHT
OUTDOORS. MOVE INSIDE A STURDY BUILDING IMMEDIATELY.



GKS/RP

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.

In the hours before

Special weather statement, Feb 27, 7:56 AM CST, 4 hours 43 minutes before
ILZ058>060-064-065-069-070-074-079-095>102-MOZ009-010-018-019-026-
027-034>036-041-042-047>052-059>065-072>075-084-085-099-261700-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
750 AM CST FRIDAY FEB 26 1999

THIS OUTLOOK COVERS THE COUNTY WARNING AREA OF THE NATIONAL WEATHER
SERVICE FORECAST OFFICE IN ST LOUIS.  AREAS INCLUDED ARE PORTIONS OF
NORTHEAST...CENTRAL...EAST CENTRAL AND SOUTHEAST MISSOURI AS WELL AS
WEST CENTRAL AND SOUTHWEST ILLINOIS.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE SOUTHEASTERN
PORTION OF THE COUNTY WARNING AREA THIS AFTERNOON AND EVENING. THE
AREA AFFECTED IS GENERALLY SOUTH AND EAST OF A CHESTERFIELD MISSOURI
TO VICHY MISSOURI LINE. THE THUNDERSTORMS WILL HAVE THE
POTENTIAL TO PRODUCE LARGE HAIL.

SKYWARN PERSONNEL AND EMERGENCY MANAGEMENT OFFICIALS SHOULD STAY
ABREAST OF LATEST FORECASTS AND OUTLOOKS SHOULD SKYWARN ACTIVATION
BECOME NECESSARY LATER TODAY.

WDB

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 27, 10:47 AM CSTSevere Thunderstorm WarningLSXCrawford33 min
Feb 27, 11:09 AM CSTSevere Thunderstorm WarningLSXFranklin46 min
Feb 27, 11:14 AM CSTSevere Thunderstorm WarningLSXWashington51 min
Feb 27, 11:22 AM CSTSevere Thunderstorm WarningLSXCrawford48 min
Feb 27, 11:24 AM CSTSevere Thunderstorm WarningLSXSaint Louis, City of Saint Louis51 min
Feb 27, 12:11 PM CSTSevere Thunderstorm WarningLSXJefferson34 min
Feb 27, 12:13 PM CSTTornado WarningLSXJefferson47 min

Nearby

Severe Thunderstorm Warnings in Missouri, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.