Severe Thunderstorm Warning 94, NWS Quad Cities, IA

Issued

Jul 20, 2002, 5:13 PM CDT (22:13 UTC)

Expired

Jul 20, 2002, 6:15 PM CDT

In force

62 min

Issued by

NWS Quad Cities, IA

Area

Counties, with a storm outline in the text

Counties Clinton County, IA, Whiteside County, IL

The Quad Cities radar (KDVN), 44 km from the middle of the area, began a volume at 22:15 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.

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.

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

338 
WUUS53 KDVN 202213
SVRMLI
IAC045-ILC195-202315-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE QUAD CITIES IA
513 PM CDT SAT JUL 20 2002

THE NATIONAL WEATHER SERVICE IN QUAD CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CLINTON COUNTY IN EAST CENTRAL IOWA
  WHITESIDE COUNTY IN NORTHWEST ILLINOIS

* UNTIL 615 PM CDT

* AT 505 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM WITH LARGE HAIL AND DAMAGING WINDS 4 MILES
  NORTHWEST OF FULTON...MOVING SOUTHWEST AT 5 MPH.

* THE SEVERE THUNDERSTORM IS EXPECTED TO BE NEAR...
   FULTON NOW.
   CLINTON BY 540 PM CDT.
   CAMANCHE BY 605 PM CDT.
   LOW MOOR BY 615 PM CDT.

THIS SEVERE THUNDERSTORM IS CAPABLE OF PRODUCING HAIL UP TO 1 INCH IN
DIAMETER AND WINDS IN EXCESS OF 55 MPH. TAKE COVER IN A STURDY
STRUCTURE UNTIL THE STORM PASSES.

THIS SEVERE THUNDERSTORM IS PRODUCING HEAVY RAINFALL...WHICH MAY
FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. AVOID THESE
AREAS AND DO NOT CROSS FLOODED ROADS AS THEY MAY BE WASHED OUT.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN QUAD CITIES.

LAT...LON 4191 9006 4200 9027 4180 9048 4176 9008


$$

JDH

NWS Quad Cities, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 2:52 PM CDT, 2 hours 21 minutes earlier.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
252 PM CDT SAT JUL 20 2002

...HIGH HEAT AND HUMIDITY MAIN CONCERNS THROUGH SUNDAY...

WARM FRONT AT MIDDAY WAS FROM FAR N CENTRAL IA CURVING SE THROUGH
DBQ INTO N CENTRAL IL. CONVECTION NOW TRYING TO FIRE ALONG
CONVERGENCE OF OUTFLOW FROM MN MCS OVER NORTHERN ZONES JUST SOUTH OF
SURFACE FRONT WHERE CAP IS WEAKEST. DEWPOINTS WIDESPREAD IN MID 70S
WITH A FEW ASOS LOCATIONS FLIRTING WITH LEGITIMATE 80 DEG READINGS
WITH AIR TEMPS IN LOW 90S PUSHING HEAT INDEX INTO ADVISORY CRITERIA
OF 105 IN A FEW LOCATIONS. INITIAL CHALLENGE IS SHORT TERM TSRA
POTENTIAL FOR NORTH...THEN HOW HOT AND HUMID CONDITIONS WILL BE
TONIGHT INTO SUNDAY.

GUIDANCE QPF HAS BEEN POINTING TOWARD WIDESPREAD CONVECTION ACROSS
EASTERN IA/NW IL ALL DAY...WHICH IS JUST NOW TRYING TO GET STARTED.
QUESTION IS HOW MUCH CAP WILL SUPPRESS CONVECTION AS OUTFLOW MOVES
SOUTH INTO HIGHLY UNSTABLE BOUNDARY LAYER WITH LAPS SB CAPES OVER 6K
J/KG. WILL CONTINUE SLIGHT CHANCES FOR NORTHEAST HALF CWA THIS
EVENING. HOW LONG PAST SUNSET CONVECTION CONTINUES IS QUESTIONABLE
WITH ONLY WEAK BOUNDARIES FOR CONVERGENCE AND UNIMPRESSIVE WIND
SHEAR SO WILL KEEP EVENING WORDING FOR NOW. GUIDANCE LOWS IN MID 70S
LOOK REASONABLE AND DEWPOINTS DO NOT DROP MUCH. DO THINK HEAT INDEX
VALUES WILL DROP BELOW 80 DEG MINS BEFORE SUNRISE AND THUS HOLD OFF
ON ADVISORY WORDING FOR TONIGHT.

HEAT ADVISORY IS NECESSARY FOR SUNDAY WITH TEMPERATURES WELL INTO
MID 90S AND POSSIBLE UPPER 90S IN FAR W-NW ZONES CLOSER TO H85 WARM
POCKET OVER NEB THAT DRIFTS NE ON SUNDAY. DEWPOINTS WILL BE SIMILAR
IF NOT A LITTLE LOWER THAN TODAY DUE TO DEEPER MIXING INTO SLIGHTLY
DRIER AIR ALOFT WITH SW FLOW AND SLIGHTLY LESS SURFACE MOISTURE
POOLING WITH FRONT FURTHER NORTH. SHOULD SEE HEAT INDEX VALUES
APPROACHING 110 IN AFTERNOON.

ALL MODELS DRIVE A COLD FRONT INTO CWFA LATE SUNDAY NIGHT/EARLY
MONDAY AS SHORTWAVE CURRENTLY MOVING ACROSS SW CANADA WI PUSHES
THROUGH. HAVE LIMITED LIKELY POPS SUNDAY NIGHT TO NW WITH SCATTERED
IN SE...AND THEN LIKELY ENTIRE AREA FOR MONDAY AS FRONT DRIVES
THROUGH. HIGH PRESSURE SETTLES IN WITH DRIER NRLY SURFACE FLOW AND
NW FLOW ALOFT TUESDAY INTO WEDNESDAY TO LIMIT HIGHS TO 80S MONDAY
AND MAINLY IN LOWER TO MID 80S TUESDAY AND WED. MEDIUM RANGE
GUIDANCE BRINGS WEAK SHORTWAVE THURSDAY INTO FRIDAY FOR TSRA
CHANCES...THEN STRONGER WAVE FRIDAY NIGHT INTO SATURDAY. GUIDANCE
TEMPERATURES LOOKED REASONABLE WITH LATE WEEK WARMING TREND.

.DVN...
IA...HEAT ADVISORY SUNDAY.
IL...HEAT ADVISORY SUNDAY.
MO...HEAT ADVISORY SUNDAY.

DLS

Severe Thunderstorm Warnings in Iowa, 2002Severe Thunderstorm Warnings in Illinois, 2002Every severe thunderstorm warning in 2002

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.