Alert archive / Illinois / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 213, NWS St. Louis, MO
NWS St. Louis, MO issued this severe thunderstorm warning at Aug 18, 1999, 11:13 PM CDT for Brown County, Illinois. It was in force for 47 min. 2 reports 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
- Aug 18, 1999, 11:13 PM CDT (04:13 UTC)
- Expired
- Aug 19, 1999, 12:00 AM CDT
- In force
- 47 min
- Issued by
- NWS St. Louis, MO
- Area
- Whole counties
County Brown County, IL
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 18, 11:15 PM CDT | Hail 1 | Cooperstown, IL | |
| Aug 18, 11:15 PM CDT | Thunderstorm Wind 51 | Cooperstown, 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 nearest sounding before it
Lincoln, IL (KILX), launched 00:00Z, 4.2 hours before the alert went out and 184 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
- 1 J/kg
- Mixed-layer CIN
- -167 J/kg
- Mixed-layer LCL
- 1415 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 172 m²/s²
- 0-3 km storm-relative helicity
- 274 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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 St. Louis, MO wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 18, 3:35 PM CDT, 7 hours 38 minutes earlier.
Area forecast discussion, Aug 18, 3:35 PM CDT, 7 hours 38 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 335 PM CDT WED AUG 18 1999 BIG-TIME WRMFNT FROM JUST SW OF COU TO JUST N OF FAM IS TRYING TO PRIME THE PUMP FOR CNVTN AS WE HEAD INTO THE EVENING HRS. SUSTAINED MSTR CNVGC OVR N MO AS WELL AS STG HTG SW OF FNTL BNDRY ERYR THIS AFTN WAS WKNG CAP. HWVR...PREFNTL TROF APRS TO BE WKNG CNVGC SM OVR AREA LAST 1-2 HRS. EVEN THO NOT TOO MUCH IN THE WAY OF DYNAMICS... STILL THINK LO LVL FORCING SHUD BE ENUF TO INITIATE CNVTN NXT FEW HRS...WITH INSTABILITY THEN FUELING THE STMS THRUOUT THE EVENING HRS ALG/AHD OF FNTL BNDRYS. SCND SHTWV SHOWING UP OVR NW WI WL BE DROPPING SWD DURG THE NEXT 24 HRS AS HGTS CONT TO FALL OVR E THIRD OF THE COUNTRY. UVV WITH THIS FTR SHUD GIVE AREAS ALG-E OF MS RVR ANOTHER CHC OF PCPN LT TNGT AND INTO THU...WHILE SHIFT IN UA PTRN WL GIVE AREA COOLER THAN NORMAL DAYTIME TEMPS FOR THE LAST PART OF THIS WK MUCH AS SUGGESTED BY CURRENT FCST TRENDS. GIVEN XTNSV CLD/TEMPS TRENDS UPSTREAM THIS AFTN...CERTAINLY APRS THAT FWC HAS TOO FEW CLDS AND ARE TOO WRM WITH TEMPS ON THU...AND PROB FRIDAY AS WELL. AGAIN...GOING ZNS LEANING TWD COOLER TEMPS AND THINK THIS STILL LKS QUITE GD. HISTORICALLY...THE LWR GUID TEMPS HV BEEN MORE CORRECT OVR MS VLY THE LAST SVRL TIMES COOLER AIR HAS INVADED AREA. .STL...NONE TRUETT
The office that day
Everything else NWS St. Louis, MO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 11:46 PM CDT | Severe Thunderstorm Warning | LSX | Pike | 44 min |
| Aug 19, 12:35 AM CDT | Severe Thunderstorm Warning | LSX | Greene | 40 min |
| Aug 19, 12:54 AM CDT | Severe Thunderstorm Warning | LSX | Macoupin | 66 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.