Tornado Watch 317

Issued

Jun 12, 2017, 1:11 PM MDT (19:11 UTC)

Expired

Jun 12, 2017, 9:00 PM MDT

In force

8 hr

Issued by

the Storm Prediction Center

Particularly dangerous situation

Yes

Largest hail expected

4 in

Strongest gust expected

65 kt

Counties Larimer County, CO, Logan County, CO, Morgan County, CO, Washington County, CO, Weld County, CO, Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sioux County, NE, Albany County, WY, Converse County, WY, Goshen County, WY, Laramie County, WY, Niobrara County, WY, Platte County, WY

The Cheyenne radar (KCYS), 96 km from the middle of the area, began a volume at 19:12 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

90%

One or more EF2 to EF5 tornadoes

80%

Ten or more severe wind reports

30%

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

80%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 995Jun 12, 11:29 AM MDT
• Mesoscale Discussion 1001Jun 12, 5:05 PM MDT
• Mesoscale Discussion 1004Jun 12, 8:02 PM MDT

246 
WWUS20 KWNS 121907
SEL7  
SPC WW 121907
COZ000-NEZ000-WYZ000-130200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 317
NWS Storm Prediction Center Norman OK
110 PM MDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northeast Colorado
  Western Nebraska Panhandle
  Southeast Wyoming

* Effective this Monday afternoon and evening from 110 PM until
  800 PM MDT.

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

* Primary threats include...
  Several tornadoes and a few intense tornadoes likely
  Widespread large hail expected with scattered very large hail
    events to 4 inches in diameter likely
  Isolated significant damaging wind gusts to 75 mph possible

SUMMARY...Isolated intense supercell thunderstorms are expected to
develop across the watch area this afternoon.  Giant hail and strong
tornadoes will be possible in the most intense storms.

The tornado watch area is approximately along and 60 statute miles
east and west of a line from 50 miles north northeast of Douglas WY
to 55 miles southeast of Fort Collins CO. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU7).

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 316...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 4 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 24030.

...Hart

Tornado Watches in Nebraska, 2017Tornado Watches in Wyoming, 2017Tornado Watches in Colorado, 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.