Alert archive / Illinois / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 58, NWS Quad Cities, IA
NWS Quad Cities, IA issued this severe thunderstorm warning at Jun 20, 1997, 6:07 PM CDT for Stephenson County, Illinois. It was in force for 63 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
- Jun 20, 1997, 6:07 PM CDT (23:07 UTC)
- Expired
- Jun 20, 1997, 7:10 PM CDT
- In force
- 63 min
- Issued by
- NWS Quad Cities, IA
- Area
- Whole counties
County Stephenson County, IL
The radar
The Quad Cities radar (KDVN), 112 km from the middle of the area, began a volume at 23:11 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 nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 11.1 hours before the alert went out and 107 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
- 2894 J/kg
- Mixed-layer CIN
- -77 J/kg
- Mixed-layer LCL
- 766 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 218 m²/s²
- 0-3 km storm-relative helicity
- 188 m²/s²
- Significant tornado parameter
- 1.6
- Supercell composite
- 12.0
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 Quad Cities, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 20, 2:16 PM CDT, 3 hours 51 minutes earlier.
Area forecast discussion, Jun 20, 2:16 PM CDT, 3 hours 51 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 200 PM CDT FRI JUN 20 1997 JET SHIFTING SLIGHTLY N OF PREVIOUS PROGS FOR TNT AND SAT. DIVERGENT THICKNESSES ALSO SLIGHTLY FURTHER N. SO EMPHASIS OF HEAVY PRECIP NORTHERN PORTION OF CWA. TIMING CHANGES ALSO INDICATED BY MODELS. FIRST PERIOD HEAVY PRECIP FOR OUR CWA THIS EVE ACCORDING TO MODELS...INSTEAD OF LATER TONIGHT AS WOULD BE CASE FOR MCC/MCS SCHENARIO. LATER TONIGHT RAIN WOULD BE LIGHT...ACCORDING TO MODELS. ALSO...SECOND PERIOD HEAVY PRECIP ON SATURDAY AFTN...ASSOCIATED WITH LOW. HIGH PRESSURE BEGINS TO BUILD IN SATURDAY NIGHT. I DON'T BUY TOTALLY INTO MODEL TIMING...THINK LATER TONIGHT WILL BE HEAVIER PRECIP SINCE TAKES A WHILE FOR MEAN RH TO INCREASE. NEVER DOES THE MEAN RH INCREASE DURING THE NIGHT ENOUGH TO PRODUCE EXCESSIVE RAIN...EXCEPT MAYBE ISOLATED AREAS. SECOND ROUND OF RAIN ON SATURDAY COULD BE MORE INTERESTING IN THIS REGARD...BUT STILL MPEAN RH NOT VERY HIGH. VEERING WINDS THROUGH TONIGHT AND INTO SATURDAY BEAR WATCHING VIS-A-VIS POTENTIAL FOR SEVERE. CID 70/70 DBQ 68/80 MLI 70/70 BRL 72/40 ARKELL
Nearby
Severe Thunderstorm Warnings in Illinois, 1997Every severe thunderstorm warning in 1997
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.