Tornado Watch 156

Issued

Apr 21, 2007, 2:10 PM MDT (20:10 UTC)

Expired

Apr 21, 2007, 9:19 PM MDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Goodland radar (KGLD), 34 km from the middle of the area, began a volume at 20:13 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

95%

One or more EF2 to EF5 tornadoes

30%

Ten or more severe wind reports

95%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

95%

One or more hailstones of 2 inches or more

40%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 525Apr 21, 1:44 PM MDT
• Mesoscale Discussion 528Apr 21, 5:10 PM MDT

000
WWUS20 KWNS 212014
SEL6  
SPC WW 212014
COZ000-KSZ000-NEZ000-220500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 156
NWS STORM PREDICTION CENTER NORMAN OK
310 PM CDT SAT APR 21 2007

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

       EASTERN COLORADO
       WESTERN KANSAS
       SOUTHWEST NEBRASKA

EFFECTIVE THIS SATURDAY AFTERNOON FROM 310 PM UNTIL MIDNIGHT CDT.

TORNADOES...HAIL TO 2.5 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 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 40 MILES WEST NORTHWEST OF
MCCOOK NEBRASKA TO 20 MILES WEST OF LIBERAL KANSAS.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU6).

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 154...WW 155...

DISCUSSION...TSTMS EXPECTED TO FORM IN THE NEXT HOUR OR SO ALONG LEE
TROUGH/DRY LINE SEGMENTS IN ERN CO/NE NM.  STORMS SHOULD QUICKLY
BECOME SUPERCELLS AND POSE A THREAT FOR TORNADOES/LARGE HAIL AS THEY
MOVE TOWARD HEATED/INCREASINGLY MOIST ENVIRONMENT ALONG WRN EDGE OF
STRATOCU FIELD IN WRN KS.  ARRIVAL OF STRENGTHENING WIND FIELD AND
LARGE SCALE ASCENT WITH POTENT NM UPR VORT WILL FAVOR EVENTUAL
DEVELOPMENT OF BROKEN LINES OF SUPERCELLS.  BUT STRENGTH OF LOW
LEVEL SHEAR AND POTENTIAL INCREASE IN SAME WITH NOCTURNAL DECOUPLING
OF LLJ MAY EXTEND TORNADO THREAT INTO MID/LATE EVENING IN ERN PARTS
OF WW.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 22040.


...CORFIDI

Tornado Watches in Kansas, 2007Tornado Watches in Colorado, 2007Tornado Watches in Nebraska, 2007Every tornado watch in 2007

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.