Tornado Watch 122

Issued

Apr 10, 2011, 6:05 PM CDT (23:05 UTC)

In effect from

Apr 10, 2011, 6:10 PM CDT

Expired

Apr 11, 2011, 1:00 AM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Quad Cities radar (KDVN), 91 km from the middle of the area, began a volume at 23:05 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.

Two or more tornadoes

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

70%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

50%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 398Apr 10, 5:03 PM CDT
• Mesoscale Discussion 404Apr 10, 11:03 PM CDT

791 
WWUS20 KWNS 102314
SEL2
SPC WW 102314
IAZ000-ILZ000-MOZ000-110600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 122
NWS STORM PREDICTION CENTER NORMAN OK
610 PM CDT SUN APR 10 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       FAR EASTERN IOWA
       WESTERN...CENTRAL AND NORTHERN ILLINOIS
       EASTERN MISSOURI

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 610 PM UNTIL
100 AM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES NORTH NORTHWEST OF
ROCKFORD ILLINOIS TO 50 MILES EAST SOUTHEAST OF JEFFERSON CITY
MISSOURI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 120...WW 121...

DISCUSSION...TSTMS EXPECTED TO INCREASE IN NUMBER AND STRENGTH
THROUGH LATE EVE ALONG MERGING DRY LINE...PRE-FRONTAL CONFLUENCE
ZONE...AND COLD FRONT FROM FAR ERN IA SWD INTO ERN MO.  OTHER STORMS
MAY FORM FARTHER E ALONG SSW-NNE BAND OF CONFLUENCE NOTED OVER CNTRL
IL.  WHILE LARGE SCALE ASCENT ATTM APPEARS TO BE DOWNWARD IN WAKE OF
PASSING UPR IMPULSE NOW ENTERING WI...LARGE SCALE ASCENT MAY
OVERSPREAD LATER THIS EVE AS JET ENTRANCE REGION EVOLVES AHEAD OF
PROGRESSIVE LARGER SCALE UPR TROUGH.  WITH SFC HEATING/LOW-LVL
CONVERGENCE ALREADY HAVING INITIATED CONVECTION/STORMS IN ERN IA/NE
MO...AND WITH THE EXPECTATION FOR INCREASING LARGE SCALE UVV LATER
THIS EVE...A POTENTIAL WILL EXIST FOR SUSTAINED STORMS.
LONG...SLIGHTLY-HOOKED HODOGRAPHS SUGGEST POSSIBILITY FOR
SUPERCELLS/LEWPS WITH TORNADOES...IN ADDITION TO SVR WIND AND HAIL.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 24045.


...CORFIDI

Tornado Watches in Illinois, 2011Tornado Watches in Missouri, 2011Tornado Watches in Iowa, 2011Every tornado watch in 2011

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.