Tornado Watch 171

Issued

Apr 28, 2017, 9:27 PM EDT (01:27 UTC)

Expired

Apr 29, 2017, 2:00 AM EDT

In force

5 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Louisville radar (KLVX), 67 km from the middle of the area, began a volume at 01:28 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

50%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 579Apr 28, 5:59 PM EDT
• Mesoscale Discussion 580Apr 28, 6:48 PM EDT
• Mesoscale Discussion 581Apr 28, 7:28 PM EDT
• Mesoscale Discussion 583Apr 28, 11:19 PM EDT
• Mesoscale Discussion 585Apr 29, 12:55 AM EDT
• Mesoscale Discussion 586Apr 29, 1:50 AM EDT

814 
WWUS20 KWNS 290124
SEL1  
SPC WW 290124
INZ000-KYZ000-290600-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 171
NWS Storm Prediction Center Norman OK
825 PM CDT Fri Apr 28 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southern Indiana
  Northern Kentucky

* Effective this Friday night and Saturday morning from 825 PM
  until 100 AM CDT.

* Primary threats include...
  A few tornadoes possible
  Scattered large hail and isolated very large hail events to 2.5
    inches in diameter possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...Clusters of storms along a surface boundary will likely
retain supercell structures for the next few hours, with an
attendant risk for large hail and damaging winds.  The near-storm
environment is favorable for some tornado risk for the next few
hours with the storms near the Ohio River, within the northern edge
of the warm sector.

The tornado watch area is approximately along and 30 statute miles
north and south of a line from 15 miles west northwest of Evansville
IN to 45 miles east of Louisville KY. 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 170...

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 550. Mean
storm motion vector 26035.

...Thompson

Tornado Watches in Indiana, 2017Tornado Watches in Kentucky, 2017Every tornado watch in 2017

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.