Alert archive / Illinois / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 76, NWS Lincoln, IL

May 17, 1999Tazewell County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at May 17, 1999, 1:06 AM CDT for Tazewell County, Illinois. It was in force for 39 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, 1:06 AM CDT (06:06 UTC)
Expired: May 17, 1999, 1:45 AM CDT
In force: 39 min
Issued by: NWS Lincoln, IL
Area: Whole counties

County Tazewell County, IL

The radar

The Lincoln radar (KILX), 42 km from the middle of the area, began a volume at 06:09 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, 1:47 AM CDT	Hail 0.88	Green Vly, 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, 6.1 hours before the alert went out and 87 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 KSPI 170607 RRA
SVRSPI
ILC179-170645-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LINCOLN IL
106 AM CDT MON MAY 17 1999

THE NATIONAL WEATHER SERVICE IN LINCOLN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  TAZEWELL COUNTY IN CENTRAL ILLINOIS

* UNTIL 145 AM CDT

* AT 106 AM CDT... DOPPLER RADAR INDICATED A LINE OF SEVERE
  THUNDERSTORMS EXTENDING FROM PEKIN TO MORTON... MOVING EAST AT 30
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  PEKIN
  MORTON
  WASHINGTON
  EAST PEORIA



DAMAGING WINDS AND LARGE HAIL CAN BE EXPECTED. MOVE TO A STURDY
BUILDING AND STAY AWAY FROM WINDOWS.

KETCHAM/PLAHMER

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 Lincoln, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at May 16, 2:20 PM CDT, 10 hours 46 minutes earlier.

Area forecast discussion, May 16, 2:20 PM CDT, 10 hours 46 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
220 PM CDT SUN MAY 16 1999

12Z ETA/AVN MODEL RUNS SEEM TO HANDLE MOVEMENT AND PLACEMENT OF SYSTEM
OVER CENTRAL PLAINS THE BEST.

TODAY...TEMPS HAVE WARMED UP NICELY WITH PLENTY OF WAA AND BREEZY S
WINDS.

FOR TONIGHT...CONVECTION WILL BEGIN TO FIRE ALONG THE BOUNDARY AND MOVE
E...SHOULD REACH EXTREME WESTERN SECTIONS OF AREA LATE TONIGHT THEN
PROGRESS THRU CWA DURING THE DAY AND EARLY EVENING HOURS. WITH THE WAA
AND SOUTHERLY WINDS...TEMPS WILL BE RATHER MILD OVERNIGHT...MIDDLE 60S.

ON MONDAY...CF WILL MOVE INTO PIA AROUND 00Z AND INTO LWV AFTER 06Z.
PCPN WILL BE HEAVY AT TIMES...BUT NOT ENOUGH TO EXCEED FFG VALUES WHICH
HAVE RECOVERED SOMEWHAT OVER CWA. SPC HAS CWA IN SLIGHT RISK FOR
MONDAY...MAINLY WITH STORMS ASSOCIATED WITH FRONTAL PASSAGE ON MONDAY
EVENING. TEMPS ON MONDAY WILL DEPEND ON CLD CVR AND PCPN...MIDDLE 70S N
TO 80 TO 85 IN THE SERN COUNTIES.

PCPN WILL PERSIST INTO THE MORNING HOURS ON TUESDAY...TAPERING OFF FROM
W TO E. THE REST OF THE FORECAST PERIOD SHOULD BE DRY AS HIGH PRESSURE
BUILDS OVER CWA.

PRELIMINARY CCF FOR COORDINATION...

SPI TW 067/078 059/071 053  68467
PIA TW 065/075 057/070 052  68667
DEC TW 066/079 059/071 053  68467
CMI TW 066/079 060/071 054  68467
MTO TW 066/080 061/071 055  68256
LWV TW 067/083 062/073 056  68256

BYRD

The office that day

Everything else NWS Lincoln, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 16, 8:02 PM CDT	Severe Thunderstorm Warning	ILX	Fulton, Mason	43 min
May 17, 12:34 AM CDT	Severe Thunderstorm Warning	ILX	Stark	41 min
May 17, 12:45 AM CDT	Severe Thunderstorm Warning	ILX	Peoria	45 min
May 17, 1:15 AM CDT	Severe Thunderstorm Warning	ILX	Woodford	45 min
May 17, 1:29 AM CDT	Severe Thunderstorm Warning	ILX	Scott	31 min
May 17, 1:40 AM CDT	Severe Thunderstorm Warning	ILX	Morgan	50 min
May 17, 1:56 AM CDT	Severe Thunderstorm Warning	ILX	Tazewell	34 min
May 17, 2:12 AM CDT	Severe Thunderstorm Warning	ILX	Cass	48 min
May 17, 2:28 AM CDT	Flash Flood Warning	ILX	Tazewell	3 hr
May 17, 7:43 AM CDT	Severe Thunderstorm Warning	ILX	Fulton, Mason	47 min
May 17, 9:46 AM CDT	Severe Thunderstorm Warning	ILX	McLean	29 min
May 17, 4:25 PM CDT	Severe Thunderstorm Warning	ILX	Clay, Effingham	65 min
May 17, 4:59 PM CDT	Severe Thunderstorm Warning	ILX	Crawford, Jasper, Richland	31 min
May 17, 5:06 PM CDT	Severe Thunderstorm Warning	ILX	Lawrence	39 min
May 17, 5:25 PM CDT	Severe Thunderstorm Warning	ILX	Clark, Crawford	35 min

Nearby

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.