Severe Thunderstorm Watch 643

Issued

Jul 14, 2011, 2:43 PM MDT (20:43 UTC)

Expired

Jul 14, 2011, 9:00 PM MDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Cheyenne radar (KCYS), 125 km from the middle of the area, began a volume at 20:44 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

10%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1615Jul 14, 1:14 PM MDT
• Mesoscale Discussion 1617Jul 14, 4:55 PM MDT
• Mesoscale Discussion 1619Jul 14, 8:05 PM MDT

242 
WWUS20 KWNS 142043
SEL3
SPC WW 142043
COZ000-KSZ000-NEZ000-WYZ000-150300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 643
NWS STORM PREDICTION CENTER NORMAN OK
240 PM MDT THU JUL 14 2011

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

       NORTHEASTERN COLORADO
       NORTHWESTERN KANSAS
       WESTERN NEBRASKA
       SOUTHEASTERN WYOMING

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 240 PM UNTIL
900 PM MDT.

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

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 95
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES EAST
NORTHEAST OF SCOTTSBLUFF NEBRASKA TO 20 MILES SOUTHEAST OF LIMON
COLORADO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 642...

DISCUSSION...VERY MOIST BOUNDARY LAYER CONDITIONS AND ADDITIONAL
HEATING WILL BE FAVORABLE FOR THUNDERSTORMS OVER NERN CO/SERN WY
HIGHER TERRAIN TO PROGRESS NEWD INTO THE PLAINS THROUGH THE EVENING
HOURS. DEEP LAYER SHEAR IS FAVORABLE FOR MULTICELL STORMS WITH
SEVERE HAIL. THE WIND DAMAGE THREAT MAY INCREASE LATER THIS EVENING
ACROSS THE EASTERN PORTIONS OF THE WATCH AS STRENGTHENING LOW LEVEL
JET MAY RESULT IN STORMS CONGEALING INTO A LINEAR MCS.

AVIATION...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 23020.


...IMY

Severe Thunderstorm Watches in Nebraska, 2011Severe Thunderstorm Watches in Colorado, 2011Severe Thunderstorm Watches in Kansas, 2011Every severe thunderstorm 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.