Tornado Watch 342

Issued

Jun 7, 2009, 3:45 PM CDT (20:45 UTC)

Expired

Jun 7, 2009, 11:00 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

3 in

Strongest gust expected

60 kt

The Omaha radar (KOAX), 118 km from the middle of the area, began a volume at 20:47 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

60%

One or more EF2 to EF5 tornadoes

40%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

40%

Ten or more severe hail reports

70%

One or more hailstones of 2 inches or more

60%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 974Jun 7, 2:36 PM CDT
• Mesoscale Discussion 979Jun 7, 5:31 PM CDT
• Mesoscale Discussion 980Jun 7, 7:08 PM CDT
• Mesoscale Discussion 982Jun 7, 8:49 PM CDT
• Mesoscale Discussion 983Jun 7, 10:22 PM CDT

671 
WWUS20 KWNS 072050
SEL2  
SPC WW 072050
IAZ000-KSZ000-MOZ000-NEZ000-080400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 342
NWS STORM PREDICTION CENTER NORMAN OK
350 PM CDT SUN JUN 7 2009

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

       SOUTHWEST IOWA
       NORTHEAST KANSAS
       NORTHWEST MISSOURI
       SOUTHEAST NEBRASKA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 350 PM UNTIL
1100 PM CDT.

TORNADOES...HAIL TO 3 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 90 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH SOUTHWEST OF
BEATRICE NEBRASKA TO 70 MILES NORTHEAST OF SAINT JOSEPH 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 341...

DISCUSSION...APPARENTLY SURFACE-BASED CONVECTION IS BEGINNING TO
DEVELOP ALONG THE SE NEB/NE KS BORDER IMMEDIATELY IN ADVANCE OF A
SURFACE WAVE ON THE FRONT...AND IN AN AREA OF STRONG INSTABILITY. 
DESPITE THE WARMING NOTED IN THE 850-700 MB LAYER IN THE 19Z TOP AND
20Z VORTEX2 SPECIAL SOUNDING IN SE NEB...COOLING IS LIKELY OCCURRING
FROM THE W WITH THE CLOUD BAND AND AN ASSOCIATED SHORTWAVE TROUGH
EJECTING NEWD OVER CENTRAL KS.  GIVEN THIS EARLY
DEVELOPMENT...THUNDERSTORM COVERAGE WILL LIKELY INCREASE THROUGH THE
AFTERNOON/EVENING.  THE STORM ENVIRONMENT IS FAVORABLE FOR
SUPERCELLS WITH VERY LARGE HAIL GIVEN STEEP MID LEVEL LAPSE
RATES...MLCAPE OF 2500-3500 J/KG...AND STRONG DEEP LAYER VERTICAL
SHEAR.  ADDITIONALLY...BOUNDARY LAYER DEWPOINTS IN THE UPPER 60S AND
BACKING/STRENGTHENING LOW-LEVEL FLOW WILL CONTRIBUTE TO AN
INCREASINGLY FAVORABLE ENVIRONMENT FOR A FEW TORNADOES THROUGH LATE
EVENING.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 25030.


...THOMPSON

Tornado Watches in Kansas, 2009Tornado Watches in Iowa, 2009Tornado Watches in Missouri, 2009Every tornado watch in 2009

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.