Tornado Watch 411

Issued

Jul 12, 2014, 4:58 PM CDT (21:58 UTC)

Expired

Jul 12, 2014, 11:19 PM CDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Des Moines radar (KDMX), 100 km from the middle of the area, began a volume at 21:58 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

60%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1345Jul 12, 3:48 PM CDT
• Mesoscale Discussion 1346Jul 12, 5:14 PM CDT
• Mesoscale Discussion 1347Jul 12, 5:51 PM CDT
• Mesoscale Discussion 1349Jul 12, 7:09 PM CDT
• Mesoscale Discussion 1350Jul 12, 9:09 PM CDT

413 
WWUS20 KWNS 122203
SEL1  
SPC WW 122203
IAZ000-ILZ000-MOZ000-130500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 411
NWS STORM PREDICTION CENTER NORMAN OK
500 PM CDT SAT JUL 12 2014

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHERN AND EASTERN IOWA
  NORTHWEST ILLINOIS
  NORTHERN MISSOURI

* EFFECTIVE THIS SATURDAY AFTERNOON FROM 500 PM UNTIL MIDNIGHT
  CDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY
  ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 100 STATUTE
MILES EAST AND WEST OF A LINE FROM 40 MILES NORTHEAST OF CEDAR
RAPIDS IOWA TO 30 MILES SOUTH SOUTHEAST OF LAMONI IOWA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

DISCUSSION...SCTD TSTMS EXPECTED TO FORM THROUGH MID-EVE IN
MOIST...VERY WARM...AND CONFLUENT WSWLY LOW-LVL FLOW AHEAD OF
ACCELERATING COLD FRONT NOW EXTENDING FROM NE IA TO SE NEB.
LARGE-SCALE ASCENT MAY BE ENHANCED BY WEAK IMPULSE TRACKING ENE
ACROSS NEB/IA AHEAD OF AMPLIFYING NRN STREAM TROUGH NOW OVER SRN MB.
COMBINATION OF STRENGTHENING LLJ...MOIST LOW-LVL
ENVIRONMENT...COOLING BOUNDARY LAYER...AND SEMI-DISCRETE STORMS
SUGGESTS POTENTIAL FOR A COUPLE TORNADOES IN ADDITION TO SVR
WIND/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 28030.


...CORFIDI

Tornado Watches in Iowa, 2014Tornado Watches in Illinois, 2014Tornado Watches in Missouri, 2014Every tornado watch in 2014

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.