Alert archive / Minnesota / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 108, NWS Grand Forks, ND

July 21, 20174 counties in Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Jul 21, 2017, 5:49 PM CDT for 4 counties in Minnesota. It was in force for 56 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 21, 2017, 5:49 PM CDT (22:49 UTC)
Expired: Jul 21, 2017, 6:45 PM CDT
In force: 56 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Becker County, MN, Clay County, MN, Otter Tail County, MN, Wilkin County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 133 km from the middle of the area, began a volume at 22:53 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.

What was reported inside it

Time	Report	Where	Remark
Jul 21, 5:53 PM CDT	HAIL 1	1 E Downer, MN	HAIL COVERED THE ROAD EAST OF DOWNER. TIME ESTIMATED BASED ON RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 4 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 21, 3:07 PM CDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 10.8 hours before the alert went out and 260 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 4 J/kg
Mixed-layer CIN: -638 J/kg
Mixed-layer LCL: 2490 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 2 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

541 
WUUS53 KFGF 212249
SVRFGF
MNC005-027-111-167-212345-
/O.NEW.KFGF.SV.W.0108.170721T2249Z-170721T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Eastern ND/Grand Forks ND
549 PM CDT FRI JUL 21 2017

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  Southern Clay County in northwestern Minnesota...
  Northern Otter Tail County in west central Minnesota...
  Northern Wilkin County in west central Minnesota...
  Southern Becker County in northwestern Minnesota...

* Until 645 PM CDT.

* At 549 PM CDT, a severe thunderstorm was located near Muskoda, or
  22 miles east of Fargo, moving east at 55 mph.

  HAZARD...60 mph wind gusts and quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees. 

* This severe thunderstorm will be near...
  Hawley around 550 PM CDT. 
  Rollag and Dale around 555 PM CDT. 
  Vergas around 620 PM CDT. 
  Butler and Hillview around 645 PM CDT. 

This includes Interstate 94 in Minnesota between mile markers 8 and
44.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4634 9516 4641 9628 4658 9676 4659 9675
      4663 9679 4675 9679 4689 9651 4698 9618
      4672 9618 4672 9516
TIME...MOT...LOC 2249Z 274DEG 46KT 4680 9636 

HAIL...1.00IN
WIND...60MPH
 
$$

JH

1 follow-up statement

999 
WWUS53 KFGF 212343
SVSFGF

Severe Weather Statement
National Weather Service Eastern ND/Grand Forks ND
643 PM CDT FRI JUL 21 2017

MNC005-027-111-167-212353-
/O.EXP.KFGF.SV.W.0108.000000T0000Z-170721T2345Z/
Clay MN-Otter Tail MN-Wilkin MN-Becker MN-
643 PM CDT FRI JUL 21 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN CLAY...NORTHERN OTTER
TAIL...NORTHERN WILKIN AND SOUTHERN BECKER COUNTIES WILL EXPIRE AT
645 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore the warning will be allowed to expire.

A severe thunderstorm watch remains in effect until 1100 PM CDT for
central, northwestern and west central Minnesota...and southeastern
North Dakota.

LAT...LON 4634 9516 4641 9628 4658 9676 4659 9675
      4663 9679 4675 9679 4689 9651 4698 9618
      4672 9618 4672 9516
TIME...MOT...LOC 2343Z 289DEG 34KT 4663 9564 

$$

JH

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Grand Forks, ND wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 21, 3:48 PM CDT, 2 hours 1 minute earlier.

Area forecast discussion, Jul 21, 3:48 PM CDT, 2 hours 1 minute before

Area Forecast Discussion
National Weather Service Grand Forks ND
348 PM CDT Fri Jul 21 2017

.SHORT TERM...(This evening through Saturday)
Issued at 341 PM CDT Fri Jul 21 2017

Still many questions in regards to convection thru the night.
Boundary located from Red Lake MN west to near Cooperstown ND. a
bit more east wind north of this boundary from earlier convection
while south winds south of this boundary with temps mid 80s to low
90s. Sfc based cape 3-4k in the RRV but where storms are nr
Cooperstown/Carrington some cap exists and still not certain
storms are rooted in boundary layer yet. Storms east toward GFK
into Crookston was elevated.

Overnight storms that are expected to fire in Manitoba may drop
southeast into NE ND but that again is not certain.

Breezy and cooler Saturday with risk of a few showers or t-storms
in NW MN.

.LONG TERM...(Saturday night through Friday)
Issued at 341 PM CDT Fri Jul 21 2017

Sunday a cool day compared to normal and then next wave with tstm
chance arriving into central/ern ND late Monday aftn and moving
east. For Tues-Fri relatively quite pattern.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 111 PM CDT Fri Jul 21 2017

VFR thru the pd outside of the t-storms where cigs/wind variable.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&

SHORT TERM...Riddle
LONG TERM...Riddle
AVIATION...Riddle

Hazardous weather outlook, Jul 21, 4:45 AM CDT, 13 hours 4 minutes before

Hazardous Weather Outlook
National Weather Service Grand Forks ND
445 AM CDT Fri Jul 21 2017

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-221200-
West Polk-Norman-Clay-Kittson-Roseau-Lake Of The Woods-
West Marshall-East Marshall-North Beltrami-Pennington-Red Lake-
East Polk-North Clearwater-South Beltrami-Mahnomen-
South Clearwater-Hubbard-West Becker-East Becker-Wilkin-
West Otter Tail-East Otter Tail-Wadena-Grant-Towner-Cavalier-
Pembina-Benson-Ramsey-Eastern Walsh County-Eddy-Nelson-
Grand Forks-Griggs-Steele-Traill-Barnes-Cass-Ransom-Sargent-
Richland-Western Walsh County-
445 AM CDT Fri Jul 21 2017

This hazardous weather outlook is for portions of eastern North
Dakota, west central and northwest Minnesota.

.DAY ONE...Today and Tonight

Severe thunderstorms are likely this afternoon and evening across
the region. However, details such as coverage, timing, and exact
location are still uncertain. The potential exists for hail up to
2 inches in diameter or greater, winds up to 75 mph, tornadoes,
and localized heavy rainfall.

Heat index values will approach 100 degrees across portions of the
area.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

The potential exists for scattered severe thunderstorms Saturday
afternoon across the northern Red River Valley and northwest
Minnesota.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is expected this afternoon.

TG

In the hours before

Local storm report, Jul 21, 5:18 PM CDT, 31 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
518 PM CDT FRI JUL 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     TSTM WND DMG     2 NE LENGBY             47.54N 95.60W
07/21/2017                   POLK               MN   PUBLIC

            BRANCHES DOWN AND POWER OUT. ONLY HAD PEA SIZED HAIL.

&&

VGODON

Special weather statement, Jul 21, 5:18 PM CDT, 31 minutes before

Special Weather Statement
National Weather Service Eastern ND/Grand Forks ND
518 PM CDT FRI JUL 21 2017

MNZ002-212315-
Norman MN-
518 PM CDT FRI JUL 21 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORMAN COUNTY UNTIL 615 PM CDT...

At 518 PM CDT, Doppler radar was tracking a strong thunderstorm over
Hadler, or 34 miles north of Fargo, moving east at 55 mph.

Half inch hail and wind gusts of 50 to 55 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Ada and Hadler around 520 PM CDT.
  Twin Valley and Gary around 535 PM CDT.
  Waukon around 540 PM CDT.
  Faith around 545 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Grand Forks.

&&

A severe thunderstorm watch remains in effect until 1100 PM CDT for
northwestern Minnesota.

LAT...LON 4716 9676 4750 9675 4750 9607 4715 9607
TIME...MOT...LOC 2218Z 276DEG 47KT 4734 9659

JH

Special weather statement, Jul 21, 5:22 PM CDT, 27 minutes before

Special Weather Statement
National Weather Service Eastern ND/Grand Forks ND
522 PM CDT FRI JUL 21 2017

MNZ006-009-017-212315-
North Beltrami MN-Lake Of The Woods MN-South Beltrami MN-
522 PM CDT FRI JUL 21 2017

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN BELTRAMI AND SOUTHEASTERN
LAKE OF THE WOODS COUNTIES UNTIL 615 PM CDT...

At 521 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles southwest of Oaks Corner to near Debs.
Movement was east at 30 mph.

Dime size hail and wind gusts up to 50 mph will be possible with
these storms.

Strong thunderstorms will be near...
  Nebish around 540 PM CDT.
  Hines around 555 PM CDT.
  Blackduck around 605 PM CDT.
  Kelliher, Shooks and Funkley around 615 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

If on a lake, get out of the water and move indoors or inside a
vehicle. Remember, lightning can strike out to 10 miles from the
parent thunderstorm. If you can hear thunder, you are close enough
to be struck by lightning. Move to safe shelter now! Do not be
caught on the water in a thunderstorm.

&&

A severe thunderstorm watch remains in effect until 1100 PM CDT for
north central Minnesota.

LAT...LON 4762 9511 4840 9514 4848 9443 4761 9442
TIME...MOT...LOC 2221Z 254DEG 28KT 4835 9505 4772 9503

jk

Local storm report, Jul 21, 5:23 PM CDT, 26 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
523 PM CDT FRI JUL 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0500 PM     HAIL             CASSELTON               46.90N 97.21W
07/21/2017  E0.88 INCH       CASS               ND   PUBLIC

            DIME TO NICKEL SIZED HAIL.

&&

VGODON

Local storm report, Jul 21, 5:27 PM CDT, 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
527 PM CDT FRI JUL 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0500 PM     TSTM WND DMG     4 SSE BAGLEY            47.47N 95.37W
07/21/2017                   CLEARWATER         MN   TRAINED SPOTTER

            WINDS BLEW OUT A WINDOW ON A HOUSE AND BROKE DOWN
            NUMEROUS LARGE BRANCHES.

0504 PM     HAIL             4 SSE BAGLEY            47.47N 95.37W
07/21/2017  E2.00 INCH       CLEARWATER         MN   TRAINED SPOTTER

            IN ADDITION TO SEVERE WINDS... LARGE HAIL COVERED THE
            GROUND.

&&

GGUST

Local storm report, Jul 21, 5:40 PM CDT, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
540 PM CDT FRI JUL 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0536 PM     TSTM WND GST     3 W BEMIDJI             47.48N 94.94W
07/21/2017  M54 MPH          BELTRAMI           MN   AWOS

            PEAK WINDS MEASURED AT THE BEMIDJI AIRPORT AWOS.

&&

GGUST

The office that day

Everything else NWS Grand Forks, ND issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 21, 1:12 PM CDT	Special Weather Statement	FGF	Roseau	63 min
Jul 21, 1:57 PM CDT	Severe Thunderstorm Warning	FGF	Beltrami, Lake of the Woods, Marshall	46 min
Jul 21, 3:37 PM CDT	Severe Thunderstorm Warning	FGF	Beltrami	23 min
Jul 21, 4:10 PM CDT	Severe Thunderstorm Warning	FGF	Norman, Polk	65 min
Jul 21, 4:15 PM CDT	Severe Thunderstorm Warning	FGF	Beltrami, Clearwater, Polk, Red Lake	60 min
Jul 21, 4:51 PM CDT	Severe Thunderstorm Warning	FGF	Becker, Beltrami, Clearwater, Hubbard, Mahnomen, Polk	54 min
Jul 21, 4:51 PM CDT	Severe Thunderstorm Warning	FGF	Clay	54 min
Jul 21, 5:18 PM CDT	Special Weather Statement	FGF	Norman	57 min
Jul 21, 5:22 PM CDT	Special Weather Statement	FGF	Beltrami	53 min
Jul 21, 5:29 PM CDT	Severe Thunderstorm Warning	FGF	Becker, Clearwater, Mahnomen	61 min
Jul 21, 5:44 PM CDT	Severe Thunderstorm Warning	FGF	Beltrami, Clearwater, Hubbard	35 min
Jul 21, 6:28 PM CDT	Severe Thunderstorm Warning	FGF	Becker	31 min
Jul 21, 6:57 PM CDT	Severe Thunderstorm Warning	FGF	Otter Tail, Wilkin	63 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2017 Every severe thunderstorm warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.