Alert archive / Missouri / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 87, NWS St. Louis, MO

May 17, 1999Ralls County, Missouri; Pike County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at May 17, 1999, 2:43 AM CDT for Ralls County, Missouri; Pike County, Illinois. It was in force for 47 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: May 17, 1999, 2:43 AM CDT (07:43 UTC)
Expired: May 17, 1999, 3:30 AM CDT
In force: 47 min
Issued by: NWS St. Louis, MO
Area: Whole counties

Counties Pike County, IL, Ralls County, MO

The radar

The St Louis radar (KLSX), 107 km from the middle of the area, began a volume at 07:46 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
May 17, 2:45 AM CDT	Hail 1	Griggsville, IL

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
May 16, 11:45 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 7.7 hours before the alert went out and 231 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: 1869 J/kg
Mixed-layer CIN: -186 J/kg
Mixed-layer LCL: 1176 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 178 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 6.8

Open this sounding in Storm Lab

The text

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

999 
WUUS1 KSTL 170745 RRA
SVRSTL
ILC149-MOC173-170830-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
243 AM CDT MON MAY 17 1999

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  PIKE COUNTY ILLINOIS IN WEST CENTRAL ILLINOIS
  RALLS COUNTY IN NORTHEASTERN MISSOURI

* UNTIL 330 AM CDT

* AT 240 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS FROM 10 MILES SOUTHWEST OF PERRY TO
  SAVERTON AND EAST TO 5 MILES WEST OF GRIGGSVILLE... MOVING
  NORTHEAST AT 20 MPH.

* LOCATIONS THAT WILL BE AFFECTED...
  CENTER
  NEW LONDON
  SAVERTON
  GRIGGSVILLE



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/WDB

The office that day

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

Issued	Product	Office	Counties	Lasted
May 17, 1:32 AM CDT	Severe Thunderstorm Warning	LSX	Audrain, Callaway, Montgomery	48 min
May 17, 2:19 AM CDT	Severe Thunderstorm Warning	LSX	Audrain, Pike	46 min
May 17, 2:19 AM CDT	Severe Thunderstorm Warning	LSX	Callaway	46 min
May 17, 1:17 PM CDT	Severe Thunderstorm Warning	LSX	Reynolds	48 min
May 17, 1:43 PM CDT	Severe Thunderstorm Warning	LSX	Madison	47 min
May 17, 2:25 PM CDT	Severe Thunderstorm Warning	LSX	Saint Clair	35 min
May 17, 3:02 PM CDT	Severe Thunderstorm Warning	LSX	Clinton, Washington	48 min
May 17, 3:39 PM CDT	Severe Thunderstorm Warning	LSX	Marion	46 min
May 17, 3:52 PM CDT	Severe Thunderstorm Warning	LSX	Fayette	48 min

Nearby

Severe Thunderstorm Warnings in Missouri, 1999 Severe Thunderstorm Warnings in Illinois, 1999 Every 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.