Tornado Watch 157

Issued

Apr 21, 2007, 3:44 PM CDT (20:44 UTC)

Expired

Apr 22, 2007, 12:00 AM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Particularly dangerous situation

Yes

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Amarillo radar (KAMA), 25 km from the middle of the area, began a volume at 20:42 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

50%

Ten or more severe wind reports

95%

One or more gusts of 65 knots or more

50%

Ten or more severe hail reports

95%

One or more hailstones of 2 inches or more

50%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 525Apr 21, 2:44 PM CDT
• Mesoscale Discussion 526Apr 21, 5:32 PM CDT
• Mesoscale Discussion 531Apr 21, 7:41 PM CDT
• Mesoscale Discussion 534Apr 21, 10:45 PM CDT

000
WWUS20 KWNS 212047
SEL7  
SPC WW 212047
OKZ000-TXZ000-220500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 157
NWS STORM PREDICTION CENTER NORMAN OK
345 PM CDT SAT APR 21 2007

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

       THE OKLAHOMA PANHANDLE
       WEST TEXAS AND THE TEXAS PANHANDLE

EFFECTIVE THIS SATURDAY AFTERNOON FROM 345 PM UNTIL MIDNIGHT CDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

DESTRUCTIVE TORNADOES...LARGE 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 20 MILES NORTH OF GUYMON
OKLAHOMA TO 10 MILES SOUTHWEST OF BIG SPRING TEXAS.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU7).

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...WW 156...

DISCUSSION...TSTMS/SUPERCELLS EXPECTED TO FORM IN THE NEXT HOUR OR
SO IN NW PART OF WW AS LEE TOUGH/DRY LINE ACCELERATES ENE FROM NM. 
ADDITIONAL STORMS MAY FORM INVOF CAPROCK ESCARPMENT/EDGE OF STRATOCU
FIELD IN THE TX PANHANDLE.  VERY STRONG LOW TO MID LEVEL SHEAR
COUPLED WITH STEEP LOW TO MID LEVEL LAPSE RATES AND FAVORABLE-TIMED
ARRIVAL OF LARGE SCALE ASCENT EXPECTED TO SUPPORT A FEW LONG-LIVED
SUPERCELLS WITH TORNADOES/LARGE HAIL.  ACTIVITY LIKELY TO EVOLVE
INTO BROKEN SEGMENTS WITH A CONTINUING THREAT FOR TORNADOES LATER
THIS EVENING AS NM VORT ACCELERATES NEWD.

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 23040.


...CORFIDI

Tornado Watches in Texas, 2007Tornado Watches in Oklahoma, 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.